Materials and Surface Treatment Processes Used for Engineering Applications

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.5	5.3	2011	17.8 Days	CHF 2400
Coatings coatings	2.9	5.0	2011	13.7 Days	CHF 2600
Materials materials	3.1	5.8	2008	15.5 Days	CHF 2600
Metals metals	2.6	4.9	2011	16.5 Days	CHF 2600
Nanomaterials nanomaterials	4.4	8.5	2010	13.8 Days	CHF 2900

12 pages, 3777 KiB

Open AccessArticle

MgAl Oxide Coatings Modified with CeO₂ Particles Formed by Plasma Electrolytic Oxidation of AZ31 Magnesium Alloy: Photoluminescent and Photocatalytic Properties

by Stevan Stojadinović and Nenad Radić

Metals 2024, 14(3), 366; https://doi.org/10.3390/met14030366 - 21 Mar 2024

Cited by 2 | Viewed by 1234

Abstract

MgAl oxide coatings composed of MgO and MgAl₂O₄ phases were doped with CeO₂ particles via plasma electrolytic oxidation (PEO) of AZ31 magnesium alloy in a 5 g/L NaAlO₂ water solution. Subsequently, particles of CeO₂ up to 8 [...] Read more.

MgAl oxide coatings composed of MgO and MgAl₂O₄ phases were doped with CeO₂ particles via plasma electrolytic oxidation (PEO) of AZ31 magnesium alloy in a 5 g/L NaAlO₂ water solution. Subsequently, particles of CeO₂ up to 8 g/L were added. Extensive investigations were conducted to examine the morphology, the chemical and phase compositions, and, most importantly, the photoluminescent (PL) properties and photocatalytic activity (PA) during the photodegradation of methyl orange. The number of CeO₂ particles incorporated into MgAl oxide coatings depends on the concentration of CeO₂ particles in the aluminate electrolyte. However, the CeO₂ particles do not significantly affect the thickness, phase structure, or surface morphology of the coatings. The PL emission spectrum of MgAl oxide coatings is divided into two bands: one in the 350–600 nm range related to structural defects in MgO, and another much more intense band in the 600–775 nm range attributed to the F⁺ centres in MgAl₂O₄. The incorporated CeO₂ particles do not have a significant effect on the PL intensity of the band in the red spectral region, but the PL intensity of the first band increases with the concentration of CeO₂ particles. The PA of MgAl/CeO₂ oxide coatings is higher than that of pure MgAl oxide coatings. The MgAl/CeO₂ oxide coating developed in aluminate electrolyte with a concentration of 2 g/L CeO₂ particles exhibited the highest PA. The MgAl/CeO₂ oxide coatings remained chemically and physically stable across multiple cycles, indicating their potential for applications. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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15 pages, 4586 KiB

Open AccessArticle

Correlation of Fabrication Methods and Enhanced Wear Performance in Nanoporous Anodic Aluminum Oxide with Incorporated Molybdenum Disulfide (MoS₂) Nanomaterials

by Kendrich O’Donaghue Hatfield, Nathan Brown, Enkeleda Dervishi, Bradley Carpenter, Jordyn N. Janusz and Daniel E. Hooks

Nanomaterials 2024, 14(5), 451; https://doi.org/10.3390/nano14050451 - 29 Feb 2024

Viewed by 1213

Abstract

Wear performance is integral to component longevity, minimizing industrial waste and excess energy costs in a wide variety of applications. Anodized aluminum oxide (AAO) has many beneficial properties leading to its wide use across industries as a surface treatment for many aluminum components, [...] Read more.

Wear performance is integral to component longevity, minimizing industrial waste and excess energy costs in a wide variety of applications. Anodized aluminum oxide (AAO) has many beneficial properties leading to its wide use across industries as a surface treatment for many aluminum components, but the wear properties of the coating could be improved significantly. Here, we used an electrochemical method to incorporate molybdenum disulfide (MoS₂), a nanomaterial used as a dry lubricant, to modify alloys of aluminum during AAO preparation. Using Raman spectroscopy and tribological scratch measurements, we thoroughly characterized the structure and wear behavior of the films. The MoS₂ deposition procedure was optimal on aluminum 5052 anodized in higher acid concentrations, with friction coefficients at around 0.05 (~10× better than unmodified AAO). Changing anodization conditions to produce harder films with smaller pores led to worsened wear properties, likely because of lower MoS₂ content. Studying a commercial MoS₂/AAO film of a different Al alloy (7075) showed that a heat treatment step intended to fully convert all deposited MoS_x species to MoS₂ can adversely affect wear in some alloys. While Al 6061 and 1100 produced films with worse wear performance compared to Al 5052 or 7075, our results show evidence that acid cleaning after initial anodization likely removes residual alloying elements, affecting MoS₂ incorporation. This study demonstrates a nanomaterial modified AAO film with superior wear characteristics to unmodified AAO and relates fabrication procedure, film structure, and practical performance. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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20 pages, 24026 KiB

Open AccessArticle

Improvement in Fatigue Strength of Chromium–Nickel Austenitic Stainless Steels via Diamond Burnishing and Subsequent Low-Temperature Gas Nitriding

by Jordan Maximov, Galya Duncheva, Angel Anchev, Vladimir Dunchev and Yaroslav Argirov

Appl. Sci. 2024, 14(3), 1020; https://doi.org/10.3390/app14031020 - 25 Jan 2024

Cited by 3 | Viewed by 866

Abstract

Chromium–nickel austenitic stainless steels are widely used due to their high corrosion resistance, good weldability and deformability. To some extent, their application is limited by their mechanical characteristics. As a result of their austenitic structure, increasing the static and dynamic strength of the [...] Read more.

Chromium–nickel austenitic stainless steels are widely used due to their high corrosion resistance, good weldability and deformability. To some extent, their application is limited by their mechanical characteristics. As a result of their austenitic structure, increasing the static and dynamic strength of the components can be achieved by surface cold work. Due to the tendency of these steels to undergo intercrystalline corrosion, another approach to improving their mechanical characteristics is the use of low-temperature thermo-chemical diffusion processes. This article proposes a new combined process based on sequentially applied diamond burnishing (DB) and low-temperature gas nitriding (LTGN) to optimally improve the fatigue strength of 304 steel. The essence of the proposed approach is to combine the advantages of the two processes (DB and LTGN) to create a zone of residual compressive stresses in the surface and subsurface layers—the enormous surface residual stresses (axial and hoop) introduced by LTGN, with the significant depth of the compressive zone characteristic of static surface cold working processes. DB (both smoothing and single-pass hardening), in combination with LTGN, achieves a fatigue limit of 600 MPa, an improvement of 36.4% compared to untreated specimens. Individually, smoothing DB, single-pass DB and LTGN achieve 540 MPa, 580 MPa and 580 MPa, respectively. It was found that as the degree of plastic deformation of the surface layer introduced by DB increases, the content of the S-phase in the nitrogen-rich layer formed by LTGN decreases, with a resultant increased content of the ε-phase and a new (also hard) phase: stabilized nitrogen-bearing martensite. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 3097 KiB

Open AccessArticle

Effect of Fine-Grained Particles and Sensitivity Analysis of Physical Indexes on Residual Strength of Granite Residual Soils

by Chen Fang, Ying Li, Chunsheng Gu and Baodong Xing

Coatings 2024, 14(1), 105; https://doi.org/10.3390/coatings14010105 - 12 Jan 2024

Viewed by 970

Abstract

Recently, stability analyses of structures built of granite residual soils, for example, earth dams or other urban structures, particularly when under vibration, are being recognized as much more important than previously imagined. In such analyses, it is emphasized that the residual strength should [...] Read more.

Recently, stability analyses of structures built of granite residual soils, for example, earth dams or other urban structures, particularly when under vibration, are being recognized as much more important than previously imagined. In such analyses, it is emphasized that the residual strength should be utilized considering the seismic effect. Therefore, the residual strength of granite residual soils must be evaluated accurately in order to reduce the damage to structures built on them. This paper presented a laboratory study designed to examine the effect of fine-grained particles (FGPs; particle size ≤ 0.075 mm) on residual strength by the multistage procedure of the Bromhead ring shear test and evaluate the physical indexes forecasting the residual strength of granite residual soils using soil samples composed of fifteen different percentages of FGPs artificially adjusted from a reservoir embankment soil sample. The results showed that the residual strength decreased along with the increase in FGPs and that the residual frictional angle was rarely dependent on the ratio of FGPs when the ratio was over 90%. Even in the residual state, a small amplitude of fluctuation in shear stress still existed and was affected by the coarse-grained particles (CGPs; particle size ≥ 0.075 mm), such as the quartz particles in the granite residual soils. It was also found that the amplitude of fluctuation was smaller when the FGP fraction was greater. In addition, under the same normal stress, the peak strength and residual strength decreased with an increase in the ratio of FGPs. Then, they remained almost the same when the ratios of FGPs were equal to 85% and 90%, respectively, and the post-peak attenuation tended to increase initially with an increase in the FGPs and then remained almost the same. Moreover, based on the sensitivity analysis, the order of influence of physical indexes on the residual frictional angle was also ranked for the granite residual soils. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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9 pages, 2900 KiB

Open AccessArticle

Enhanced Performance of GaAs Metal-Oxide-Semiconductor Capacitors Using a TaON/GeON Dual Interlayer

by Lu Liu, Wanyu Li, Fei Li and Jingping Xu

Nanomaterials 2023, 13(19), 2673; https://doi.org/10.3390/nano13192673 - 29 Sep 2023

Viewed by 1004

Abstract

In this work, a dual interfacial passivation layer (IPL) consisting of TaON/GeON is implemented in GaAs metal-oxide-semiconductor (MOS) capacitors with ZrTaON as a high-k layer to obtain superior interfacial and electrical properties. As compared to the samples with only GeON IPL or no [...] Read more.

In this work, a dual interfacial passivation layer (IPL) consisting of TaON/GeON is implemented in GaAs metal-oxide-semiconductor (MOS) capacitors with ZrTaON as a high-k layer to obtain superior interfacial and electrical properties. As compared to the samples with only GeON IPL or no IPL, the sample with the dual IPL of TaON/GeON exhibits the best performance: low interface-state density (1.31 × 10¹² cm⁻² eV⁻¹), small gate leakage current density (1.62 × 10⁻⁵ A cm⁻² at V_fb + 1 V) and large equivalent dielectric constant (18.0). These exceptional results can be attributed to the effective blocking action of the TaON/GeON dual IPL. It efficiently prevents the out-diffusion of Ga/As atoms and the in-diffusion of oxygen, thereby safeguarding the gate stack against degradation. Additionally, the insertion of the thin TaON layer successfully hinders the interdiffusion of Zr/Ge atoms, thus averting any reaction between Zr and Ge. Consequently, the occurrence of defects in the gate stack and at/near the GaAs surface is significantly reduced. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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13 pages, 4747 KiB

Open AccessArticle

Effect of Thermal Oxygen Conditions on the Long-Term Aging Behavior of High-Viscosity Modified Bitumen

by Chengwei Xing, Juze Qin, Mingchen Li and Tian Jin

Coatings 2023, 13(8), 1421; https://doi.org/10.3390/coatings13081421 - 13 Aug 2023

Viewed by 1037

Abstract

High-viscosity modified bitumen is affected by a complex thermal oxygen environment during long-term service. However, the existing standard long-term thermal oxygen aging test cannot fully simulate the effect of different thermal oxygen conditions on the aging of high-viscosity modified bitumen. In this study, [...] Read more.

High-viscosity modified bitumen is affected by a complex thermal oxygen environment during long-term service. However, the existing standard long-term thermal oxygen aging test cannot fully simulate the effect of different thermal oxygen conditions on the aging of high-viscosity modified bitumen. In this study, on the basis of the standard pressure aging vessel test, high-viscosity modified bitumen was aged under different oxygen conditions through adjusting test parameters. Then, the analysis of the complex moduli, phase angles, and creep and recovery properties was conducted to evaluate the rheological properties of high-viscosity modified bitumen before and after aging. Moreover, gel permeation chromatography was performed to evaluate the molecular size distribution of high-viscosity modifiers during aging. The results indicate that aging improves the modulus of high-viscosity modified bitumen and changes the phase angle of that. Temperature, pressure, and time are the factors affecting the high-temperature sensitivity and viscoelastic properties of high-viscosity modified bitumen. With respect to the creep and recovery property, different high-viscosity modified bitumen exhibits different aging characteristics with the change of thermal oxygen conditions. Gel-permeation-chromatography results directly illustrate that thermal oxygen conditions influence the degradation of high-viscosity modifiers at the initial stage of long-term aging, which is the key factor affecting the rheological properties of high-viscosity modified bitumen. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 4444 KiB

Open AccessArticle

Assessment of Processing Parameters of Pack Silicon Cementation onto P265GH Grade Steel

by Mihai Ovidiu Cojocaru, Mihai Branzei and Mircea Dan Morariu

Materials 2023, 16(15), 5397; https://doi.org/10.3390/ma16155397 - 1 Aug 2023

Viewed by 1025

Abstract

The quantification of the single or combined variation of the process parameters specific to a thermochemical treatment is the key to a full factorial experiment and a first step in the development of computer-aided process engineering. Powdery solid media are frequently used in [...] Read more.

The quantification of the single or combined variation of the process parameters specific to a thermochemical treatment is the key to a full factorial experiment and a first step in the development of computer-aided process engineering. Powdery solid media are frequently used in the practice of thermochemical treatments when the number of processed products is reduced, additional investments are not justified, or when there are no technological alternatives. The control of the process carried out in such powdery solid media involves both the control of the thermal and temporal parameters of the process on the layer growth kinetics and its phase composition, as well as the ratio of the powdery solid mixture mass percentage (active and neutral components, reaction activators, and components with the role of blocking the sintering tendency of the medium particles). In this paper, using the specific full factorial experiment (that is, a first-order complete factorial experiment (CFE)), the full model of the regression equation of the interactions between the specific process parameters of the silicide layer formation in a powdery solid media, applied to the low alloy P265GH steel grade and used in the petrochemical industry, were evaluated. Fe-ARMCO was chosen as the reference in the experimental research carried out. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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17 pages, 10326 KiB

Open AccessArticle

A Comparative Study on Characterization and High-Temperature Wear Behaviors of Thermochemical Coatings Applied to Cobalt-Based Haynes 25 Superalloys

by Ali Günen and Ömer Ergin

Coatings 2023, 13(7), 1272; https://doi.org/10.3390/coatings13071272 - 20 Jul 2023

Cited by 9 | Viewed by 1678

Abstract

This study investigated the characteristic properties of aluminizing, boronizing, and boro-aluminizing coatings grown on Haynes 25 superalloys and their effects on the high-temperature wear behavior. The coating processes were conducted in a controlled atmosphere at 950 °C for 3 h. Characterization studies were [...] Read more.

This study investigated the characteristic properties of aluminizing, boronizing, and boro-aluminizing coatings grown on Haynes 25 superalloys and their effects on the high-temperature wear behavior. The coating processes were conducted in a controlled atmosphere at 950 °C for 3 h. Characterization studies were performed using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction analysis, nanoindentation testing, and high-temperature wear tests. It was determined that the thickness values of aluminide, boride, and boride–aluminide coatings were 140 ± 1.50 µm, 37.58 ± 2.85 µm, and 14.73 ± 1.71 µm, and their hardness values were 12.23 ± 0.9 GPa, 26.34 ± 2.33 GPa, and 23.46 ± 1.29 GPa, respectively. The hardness of the coatings resulted in reduced wear volume losses both at room temperature and at 500 °C. While the best wear resistance was obtained in the boronized sample at room temperature due to its high hardness, the best wear resistance at 500 °C was obtained in the boro-aluminized sample with the oxidation–reduction effect of Al content and the lubricating effect of B content in the boro-aluminide coating. This indicates that the presence of aluminum in boride layers improves the high-temperature wear resistance of boride coatings. The coated samples underwent abrasive wear at room temperature, whereas at 500 °C, the wear mechanism shifted to an oxidative-assisted adhesive wear mechanism. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 4324 KiB

Open AccessArticle

Concentration Influence of Complexing Agent on Electrodeposited Zn-Ni Alloy

by Byung-Ki Son, Ji-Won Choi, Su-Byung Jeon and In-Joon Son

Appl. Sci. 2023, 13(13), 7887; https://doi.org/10.3390/app13137887 - 5 Jul 2023

Cited by 1 | Viewed by 1574

Abstract

Zinc (Zn) coatings, which are widely used to protect metals from corrosion, can be further improved by alloying with nickel (Ni). Increasing the Ni content enhances the corrosion-resistant properties of the Zn coating. This study investigated the effect of tetraethylenepentamine (TEPA) concentration on [...] Read more.

Zinc (Zn) coatings, which are widely used to protect metals from corrosion, can be further improved by alloying with nickel (Ni). Increasing the Ni content enhances the corrosion-resistant properties of the Zn coating. This study investigated the effect of tetraethylenepentamine (TEPA) concentration on the Ni content and the properties of the Zn-Ni alloy coating. Zn-Ni alloy coatings were electrodeposited via the Hull cell test with TEPA concentrations of 0, 0.035, 0.07, and 0.1 M. We found that increasing the TEPA concentration improved the brightness of the coating at low current density and influenced the crystal orientation and morphology. When the TEPA concentration was increased to 0.7 M, the Ni content of the Zn-Ni alloy coating significantly increased before leveling off. However, the thickness of the coatings decreased with increasing TEPA concentration. The electrochemical behavior of the Zn-Ni alloy electrodeposition was validated via partial polarization curves of the Zn and Ni depositions. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 8625 KiB

Open AccessArticle

Effect of Temperature on the Morphology and Corrosion Resistance of Modified Boron Nitride Nanosheets Incorporated into Steel Phosphate Coating

by Mustafa Muhammad, Ruina Ma, An Du, Yongzhe Fan, Xue Zhao, Niu Jun and Xiaoming Cao

Metals 2023, 13(7), 1186; https://doi.org/10.3390/met13071186 - 26 Jun 2023

Viewed by 1449

Abstract

In this study, the impact of various temperatures (25 °C, 45 °C, and 55 °C) on q235 steel specimens was studied to analyze the influence on the morphology and corrosion resistance of modified boron nitride nanosheets incorporated into the phosphate coating. The morphology [...] Read more.

In this study, the impact of various temperatures (25 °C, 45 °C, and 55 °C) on q235 steel specimens was studied to analyze the influence on the morphology and corrosion resistance of modified boron nitride nanosheets incorporated into the phosphate coating. The morphology and surface modification of the coating were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). SEM results showed that the S-45 steel sample produced a higher number of nucleation sites and reduced grain size with a denser, more robust, and more corrosion-resistant phosphate coating compared to the S-25 and S-55 samples, respectively. The potentiodynamic polarization results demonstrate that the S-45 steel sample exhibited the best corrosion resistance performance with an electric current density of 5.48 × 10⁻⁸ A/cm², an order of magnitude lower than the S-25 and S-55 samples, respectively. The coating weight results showed that the S-45 steel specimen achieved the densest and most uniform coating (32.14 g/m²). Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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17 pages, 3769 KiB

Open AccessArticle

Microstructural and Mechanical Behavior Investigations of Nb-Reinforced Mg–Sn–Al–Zn–Mn Matrix Magnesium Composites

by Ali Ercetin, Özgür Özgün, Kubilay Aslantaş, Oguzhan Der, Bekir Yalçın, Ercan Şimşir and Muhammad Aamir

Metals 2023, 13(6), 1097; https://doi.org/10.3390/met13061097 - 10 Jun 2023

Cited by 7 | Viewed by 1552

Abstract

This research focuses on the fabrication and characterization of TAZ532-xNb composites, employing high-purity, micron-sized powders of Mg, Sn, Al, Zn, Mn, and Nb as the raw materials. These powders were subjected to a paraffin coating process aimed at mitigating oxidation. The formation of [...] Read more.

This research focuses on the fabrication and characterization of TAZ532-xNb composites, employing high-purity, micron-sized powders of Mg, Sn, Al, Zn, Mn, and Nb as the raw materials. These powders were subjected to a paraffin coating process aimed at mitigating oxidation. The formation of composites was achieved via hot pressing and was followed by surface preparation and analysis using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). An X-ray diffraction (XRD) study was conducted to identify the microstructural phases. Quantitative assessments including the theoretical density, actual density, and relative density were computed, and their fluctuations in relation to the increasing Nb reinforcement ratio were scrutinized. Furthermore, the mechanical attributes of the composites, such as hardness and tensile strength, were assessed via experimental procedures. The absence of oxygen-related peaks in the XRD patterns endorsed the successful execution of the paraffin coating technique and protective gas atmosphere during sintering. The detection of α-Mg, Mg₂Sn, MgZn, Mg₁₇Al₁₂, and Nb phases within the Nb-reinforced composite patterns authenticated the formation of the intended phases. Notably, the relative density values of the composites surpassed 95%, indicating efficient sintering. SEM results disclosed a densely packed microstructure, with Nb reinforcement particles evenly distributed along the grain boundaries, devoid of particle clustering or significant grain growth. These composites manifested exceptional wetting characteristics, which can be attributed to the employment of Mg alloy as the matrix material. EDS data confirmed the proportions of Nb within the composites, aligning with the quantities incorporated during fabrication. The composites showcased an increase in microhardness values with the escalating Nb reinforcement ratio, credited to the harder constitution of Nb particles in comparison to the matrix alloy. Concurrently, tensile strength showed a significant improvement with the increment in Nb reinforcement, while elongation values peaked at a specific Nb reinforcement level. The positive evolution of tensile strength properties was ascribed to the escalated Nb reinforcement ratio, grain size, and consequent higher sample densities. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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15 pages, 3917 KiB

Open AccessReview

Multifunctional Integrated Underwater Sound Absorption Materials: A Review

by Xianmei Chen, Lei Meng, Zibo Liu, Feiran Yang, Xin Jiang and Jun Yang

Appl. Sci. 2023, 13(9), 5368; https://doi.org/10.3390/app13095368 - 25 Apr 2023

Cited by 4 | Viewed by 3550

Abstract

Rapid improvements in underwater vehicle technology have led to a significant increase in the demand for underwater sound absorption materials. These materials, unlike their counterparts utilized in air, must have high hydrostatic pressure resistance, corrosion resistance, and other advantageous attributes. This necessitates the [...] Read more.

Rapid improvements in underwater vehicle technology have led to a significant increase in the demand for underwater sound absorption materials. These materials, unlike their counterparts utilized in air, must have high hydrostatic pressure resistance, corrosion resistance, and other advantageous attributes. This necessitates the development of innovative, composite sound-absorbing materials with multifunctional properties, which presents substantial challenges for researchers. In this comprehensive review, we systematically analyze and categorize the mechanisms governing underwater sound absorption, hydrostatic pressure resistance, and corrosion prevention while considering related research advances. Furthermore, we provide an extensive overview of research advancements, existing challenges, and potential solutions pertaining to multifunctional and integrated underwater sound-absorbing materials. This review aims to serve as a valuable resource for future investigations into the development and optimization of multifunctional integrated underwater sound-absorbing materials, thereby contributing to the advancement of underwater vehicle technology. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 4176 KiB

Open AccessArticle

A Comparative Investigation of the Surface Properties of Corn-Starch-Microfibrillated Cellulose Composite Films

by Zuzanna Żołek-Tryznowska, Ewa Bednarczyk, Mariusz Tryznowski and Tomasz Kobiela

Materials 2023, 16(9), 3320; https://doi.org/10.3390/ma16093320 - 23 Apr 2023

Cited by 11 | Viewed by 1960

Abstract

Starch-based materials seem to be an excellent alternative for conventional plastics used in various applications. Microfibralted cellulose can be used to improve the surface properties of starch-based materials. This study aims to analyze the surface properties of starch-microfibrillated cellulose materials. The surface properties [...] Read more.

Starch-based materials seem to be an excellent alternative for conventional plastics used in various applications. Microfibralted cellulose can be used to improve the surface properties of starch-based materials. This study aims to analyze the surface properties of starch-microfibrillated cellulose materials. The surface properties of films were evaluated by ATR-FTIR, surface roughness, water wettability, and surface free energy. The surface homogeneity between corn starch and microfibrillated cellulose (MFC) fibers was confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Microscopic analyses of the film surfaces confirm good compatibility of starch and MFC. The addition of MFC increased the surface roughness and polarity of developed starch/MFC materials. The surface roughness parameter has increased from 1.44 ± 0.59 to 2.32 ± 1.13 for pure starch-based materials and starch/MFC material with the highest MFC content. The WCA contact angle has decreased from 70.3 ± 2.4 to 39.1 ± 1.0°, while the surface free energy is 46.2 ± 3.4 to 66.2 ± 1.5 mJ·m⁻², respectively. The findings of this study present that surface structure starch/MFC films exhibit homogeneity, which would be helpful in the application of MFC/starch materials for biodegradable packaging purposes. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 6903 KiB

Open AccessArticle

Microstructure Characterization and Strengthening Mechanism Analysis of X100 Pipeline Steel

by Xiaoyu Ye, Shaohua Cui, Tao Liu, Qilin Ma, Gang Liu, Zhenyi Huang, Jie Guo and Shubiao Yin

Coatings 2023, 13(4), 706; https://doi.org/10.3390/coatings13040706 - 30 Mar 2023

Cited by 2 | Viewed by 1735

Abstract

The strengthening mechanism of X100 high steel grade pipeline steel, including grain boundary strengthening, solution strengthening, precipitation strengthening, dislocation strengthening, and texture strengthening, was analyzed by the technics of scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), X-ray diffraction [...] Read more.

The strengthening mechanism of X100 high steel grade pipeline steel, including grain boundary strengthening, solution strengthening, precipitation strengthening, dislocation strengthening, and texture strengthening, was analyzed by the technics of scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), X-ray diffraction (XRD), physicochemical phase analysis, and so on. The results showed that the tested steel had a mixed structure of granular bainite and lath bainite, the average effective grain size was refined to about 1 μm by severe hot plastic deformation, the dislocation density was as high as 1.74 × 10¹⁵/m², and the second phase precipitation was mainly (Ti, Nb)(C, N) in submicron scale and nanoscale NbC. Through orientation distribution function (ODF) orientation analysis, it was found that the tested steel had obvious anisotropy and had a strong rolling direction (RD) texture along the rolling direction compared with the 30° direction: {115}<110> and {113}<110>. After the quantitative analysis of strengthening mechanisms, it was found that the highest strengthening increment was caused by high-density dislocations in bainite of about 268 MPa, while the lowest strengthening increment was induced by precipitation particles of about 31 MPa. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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20 pages, 4827 KiB

Open AccessArticle

Improving the Surface Properties of an API 5L Grade B Pipeline Steel by Applying the Boriding Process—Part II: On the Changes in the Mechanical Properties

by Laura Montserrat Alcantar-Martínez, Pablo Alfredo Ruiz-Trabolsi, Raúl Tadeo-Rosas, José Guadalupe Miranda-Hernández, Román Cabrera-Sierra, Julio César Velázquez and Enrique Hernández-Sánchez

Coatings 2023, 13(2), 470; https://doi.org/10.3390/coatings13020470 - 18 Feb 2023

Cited by 5 | Viewed by 2441

Abstract

The mechanical performance of API 5L grade B steel, after undergoing a thermochemical boriding process, was assessed. We quantified the boride layer microhardness over cross-section specimens, with the aim of characterizing the mechanical resistance under different conditions. The pipeline steel was analyzed because [...] Read more.

The mechanical performance of API 5L grade B steel, after undergoing a thermochemical boriding process, was assessed. We quantified the boride layer microhardness over cross-section specimens, with the aim of characterizing the mechanical resistance under different conditions. The pipeline steel was analyzed because of the changes in yield strength, ultimate tensile strength, and ductility after treatment with boron. These oil and gas pipelines must work in aggressive environments, so borided pipeline steel specimens were tested to assess their erosion–corrosion resistance. Another important characteristic to evaluate was the wearing resistance, because the pipelines tend to suffer scratches when they are under construction. We also present a discussion of the results of the total research work (Part I and Part II), including the results of the boride layer characterization as well as the changes in the substrate, with the goal of selecting the best conditions under which to treat pipeline steel. More extreme treatment conditions can help to form more stable and resistant boride layers, but they can considerably modify some mechanical characteristics of the API 5L grade B steel. For this reason, the boriding treatment conditions must be chosen in a synergistic way. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 5734 KiB

Open AccessArticle

The Piezoresponse in WO₃ Thin Films Due to N₂-Filled Nanovoids Enrichment by Atom Probe Tomography

by Pamela M. Pineda-Domínguez, Torben Boll, John Nogan, Martin Heilmaier, Abel Hurtado-Macías and Manuel Ramos

Materials 2023, 16(4), 1387; https://doi.org/10.3390/ma16041387 - 7 Feb 2023

Cited by 1 | Viewed by 2040

Abstract

Tungsten trioxide (WO₃) is a versatile n-type semiconductor with outstanding chromogenic properties highly used to fabricate sensors and electrochromic devices. We present a comprehensive experimental study related to piezoresponse with piezoelectric coefficient d₃₃ = 35 pmV⁻¹ on WO [...] Read more.

Tungsten trioxide (WO₃) is a versatile n-type semiconductor with outstanding chromogenic properties highly used to fabricate sensors and electrochromic devices. We present a comprehensive experimental study related to piezoresponse with piezoelectric coefficient d₃₃ = 35 pmV⁻¹ on WO₃ thin films ~200 nm deposited using RF-sputtering onto alumina (Al₂O₃) substrate with post-deposit annealing treatment of 400 °C in a 3% H₂/N₂-forming gas environment. X-ray diffraction (XRD) confirms a mixture of orthorhombic and tetragonal phases of WO₃ with domains with different polarization orientations and hysteresis behavior as observed by piezoresponse force microscopy (PFM). Furthermore, using atom probe tomography (APT), the microstructure reveals the formation of N₂-filled nanovoids that acts as strain centers producing a local deformation of the WO₃ lattice into a non-centrosymmetric structure, which is related to piezoresponse observations. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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23 pages, 4407 KiB

Open AccessArticle

Improving the Surface Properties of an API 5L Grade B Pipeline Steel by Applying the Boriding Process. Part I: Kinetics and Layer Characterization

by Laura Montserrat Alcantar-Martínez, Pablo Alfredo Ruiz-Trabolsi, Raúl Tadeo-Rosas, José Guadalupe Miranda-Hernández, Gerardo Terán-Méndez, Julio César Velázquez and Enrique Hernández-Sánchez

Coatings 2023, 13(2), 298; https://doi.org/10.3390/coatings13020298 - 28 Jan 2023

Cited by 5 | Viewed by 2586

Abstract

Although the use and promotion of renewable energies have increased in recent years, it is evident that the use of fossil fuels such as oil and gas continues to be of great importance. Likewise, pipelines are widely recognized as the most reliable and [...] Read more.

Although the use and promotion of renewable energies have increased in recent years, it is evident that the use of fossil fuels such as oil and gas continues to be of great importance. Likewise, pipelines are widely recognized as the most reliable and profitable means of transportation for liquid and gaseous hydrocarbons. Nevertheless, due to the nature of hydrocarbons, oil and gas pipelines are continually exposed to deterioration by corrosion and mechanical damage. In this context, this research focuses on the improvement of the surface properties of API 5L grade B pipeline steel by applying a surface hardening process. Samples of an API 5L grade B pipeline steel were exposed to boriding to form a layer of high hardness (from 2.60 GPa for the non-treated material to 14.12 GPa for the samples exposed to 1000 °C for 6 h). The treatment time was set at 2, 4, and 6 h, at temperatures of 850, 900, 950, and 1000 °C. Due to the saw-tooth morphology of the layers and the random nature of the process, it was possible to fit their thicknesses to a probability density function in all the experimental conditions. The crystalline structure of the layers was analyzed by X-ray diffraction and the morphology was observed using SEM and optical microscopy. The layer’s thickness ranged between 26.6 µm to 213.9 µm showing a close relationship with the experimental parameters of time and temperature. Finally, it is studied the changes undergone in the pipeline steel after the thermochemical process, observing an increase in the grain size as a function of the temperature. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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17 pages, 7738 KiB

Open AccessArticle

Enhancing the Surface Hydrophilicity of an Aluminum Alloy Using Two-Step Anodizing and the Effect on Inkjet Printing Characteristics

by Youngyoon Kim and Wook-Bae Kim

Coatings 2023, 13(2), 232; https://doi.org/10.3390/coatings13020232 - 19 Jan 2023

Cited by 3 | Viewed by 2614

Abstract

Aluminum alloy anodizing is widely used in the surface treatment industry to provide surface protection and decoration. The resulting anodic aluminum oxide film enables durable printing and dyeing of metals owing to its nanoporous structure, which easily absorbs ink. Conventional one-step anodizing of [...] Read more.

Aluminum alloy anodizing is widely used in the surface treatment industry to provide surface protection and decoration. The resulting anodic aluminum oxide film enables durable printing and dyeing of metals owing to its nanoporous structure, which easily absorbs ink. Conventional one-step anodizing of Al 1050 using sulfuric acid was observed to form a surface with small pore diameters less than 10 nm and lead to an average contact angle of 30°, whereas two-step anodizing yielded a regular pore pattern with significantly larger pores, reducing the contact angle to less than 20°. This change in pore structure and the corresponding enhanced hydrophilicity directly impacted inkjet printing characteristics; inkjet printing of 13 pL droplets on the one-step and two-step anodized surfaces showed that the average dot diameter varied from 72.2 μm to 48.0 μm according to applied voltage and anodizing time. The ink dot diameters on the two-step film were smaller than those on the one-step film produced under the same conditions, and the dot diameters decreased as the average pore diameter increased under an increasing anodizing voltage up to 20 V, indicating improved hydrophilicity. The pore volumes produced by two-step anodizing were larger, facilitating ink droplet absorption during spreading, which was examined by elemental analysis of cross-sections of the ink-filled porous specimen. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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13 pages, 5917 KiB

Open AccessArticle

Synthesis of RGO/Cu@ FeAl₂O₄ Composites and Its Applications in Electromagnetic Microwave Absorption Coatings

by Zhenhua Chu, Wenxing Deng, Jingxiang Xu, Fang Wang, Zheng Zhang and Qingsong Hu

Materials 2023, 16(2), 740; https://doi.org/10.3390/ma16020740 - 12 Jan 2023

Cited by 1 | Viewed by 2135

Abstract

In order to satisfy the requirements of wide frequency bands, the lightweight and strong absorption for the electromagnetic wave absorbing materials, a uniform mixture of FeAl₂O₄ with RGO/Cu (reduction graphene oxide, RGO) was obtained by the mechanical mixing method, and [...] Read more.

In order to satisfy the requirements of wide frequency bands, the lightweight and strong absorption for the electromagnetic wave absorbing materials, a uniform mixture of FeAl₂O₄ with RGO/Cu (reduction graphene oxide, RGO) was obtained by the mechanical mixing method, and composite coating was obtained by plasma spraying. The addition of RGO/Cu into FeAl₂O₄ is conducive to improve the dielectric properties and the impedance matching performance of spinel. When the RGO/Cu composite powders are doped by 10 wt.%, the reflection loss at 15 GHz is −16 dB and the absorption bandwidth is 2 GHz, indicating that the composite material has potential application value in the field of high-frequency wave absorption. The research on the electromagnetic wave absorption mechanism shows that its superior wave absorption performance is determined by the synergistic effect of multiple loss mechanisms such as interfacial polarization, dipole relaxation, natural resonance, exchange resonance, and eddy current loss. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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17 pages, 9034 KiB

Open AccessArticle

Hydroxyapatite Growth on Activated Carbon Surface for Methylene Blue Adsorption: Effect of Oxidation Time and CaSiO₃ Addition on Hydrothermal Incubation

by Anastasio Moreno-Santos, Jorge Carlos Rios-Hurtado, Sergio Enrique Flores-Villaseñor, Alma Graciela Esmeralda-Gomez, Juanita Yazmin Guevara-Chavez, Fatima Pamela Lara-Castillo and Griselda Berenice Escalante-Ibarra

Appl. Sci. 2023, 13(1), 77; https://doi.org/10.3390/app13010077 - 21 Dec 2022

Cited by 2 | Viewed by 1933

Abstract

Many adsorbent materials are now commercially available; however, studies have focused on modifying them to enhance their properties. In this study, an activated carbon (AC) and hydroxyapatite (HAp) composite was synthesized by the immersion of ACs in a simulated body fluid solution, varying [...] Read more.

Many adsorbent materials are now commercially available; however, studies have focused on modifying them to enhance their properties. In this study, an activated carbon (AC) and hydroxyapatite (HAp) composite was synthesized by the immersion of ACs in a simulated body fluid solution, varying the AC oxidation degree along with the addition of CaSiO₃. The resulting composites were characterized by ash %, X-ray fluorescence (XRF), Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and point of zero charge (PZC). The characterization results indicated that the addition of CaSiO₃ and the oxygenated functional groups in the AC surface are key factors for HAp growth. The composites were tested on methylene blue (MB) adsorption as a potential application for the synthesized materials. Adsorption isotherms were modeled with Langmuir and Freundlich isotherms, and the composites were fitted to a Langmuir model with the highest q_max value of 9.82. The kinetic results indicated that for the pseudo-second-order model, the composites fitted, with a contact time of 180 min to remove a 95.61% average of the MB. The results indicate that composite materials can be an efficient adsorbent for the removal of MB from aqueous solutions at low concentrations since the material with the highest amount of HAp growth removed 99.8% of the MB in 180 min. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 7429 KiB

Open AccessArticle

Optimizing the Infrared Photoelectric Detection Performance of Pbs Quantum Dots through Solid-State Ligand Exchange

by Mei Yang, Huan Liu, Shuai Wen, Yuxuan Du and Fei Gao

Materials 2022, 15(24), 9058; https://doi.org/10.3390/ma15249058 - 19 Dec 2022

Cited by 3 | Viewed by 2296

Abstract

Lead sulfide (PbS) quantum dots (QDs) have attracted a great deal of attention in recent decades, due to their value for applications in optoelectronic devices. However, optimizing the performance of optoelectronic devices through ligand engineering has become a major challenge, as the surfactants [...] Read more.

Lead sulfide (PbS) quantum dots (QDs) have attracted a great deal of attention in recent decades, due to their value for applications in optoelectronic devices. However, optimizing the performance of optoelectronic devices through ligand engineering has become a major challenge, as the surfactants that surround quantum dots impede the transport of electrons. In this paper, we prepared PbS QD films and photoconductive devices with four different ligands: 1,2-ethylenedithiol (EDT), tetrabutylammonium iodide (TBAI), hexadecyl trimethyl ammonium bromide (CTAB), and sodium sulfide (Na₂S). A series of characterization studies confirmed that using the appropriate ligands in the solid-state ligand exchange step for thin film fabrication can significantly improve the responsivity. The devices treated with sodium sulfide showed the best sensitivity and a wider detection from 400 nm to 2300 nm, compared to the other ligand-treated devices. The responsivity of the champion device reached 95.6 mA/W under laser illumination at 980 nm, with an intensity of 50 mW/cm². Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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13 pages, 5248 KiB

Open AccessArticle

Analysis and Prediction of Grind-Hardening Surface Roughness Based on Response Surface Methodology-BP Neural Network

by Chunyan Wang, Guicheng Wang and Chungen Shen

Appl. Sci. 2022, 12(24), 12680; https://doi.org/10.3390/app122412680 - 10 Dec 2022

Cited by 6 | Viewed by 1842

Abstract

Surface morphology and surface roughness are very important properties used to assess the quality of grind-hardening surfaces. In this study, grind-hardening tests for 42CrMo steel were designed using the response surface methodology to reveal the surface morphological characteristics of the grind-hardening surface and [...] Read more.

Surface morphology and surface roughness are very important properties used to assess the quality of grind-hardening surfaces. In this study, grind-hardening tests for 42CrMo steel were designed using the response surface methodology to reveal the surface morphological characteristics of the grind-hardening surface and the effects of grinding parameters on its roughness. The results showed considerable grinding damage in both the cutting-in and cutting-out areas of the grind-hardened surface, while the middle area was more stable. More specifically, the cutting-in area showed much bonding and damage, while the cutting-out area showed more microcracks. Under the conditions of this test, the surface roughness tended to increase with the increase in cutting depth and workpiece feed speed. The effect of grinding line speed on the grind-hardening surface roughness was not significant. The significance of the effects of grinding parameters on surface roughness ranked as: cutting depth > workpiece feed speed > grinding speed. In turn, a response surface methodology-BP neural network prediction model for the surface roughness of grind-hardening was developed, whose feasibility and validity were confirmed by the experimental results. The model achieved surface roughness prediction of the grind-hardening process with a mean relative error of 2.86%. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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12 pages, 3223 KiB

Open AccessArticle

Energetic and Protective Coating via Chemical and Physical Synergism for High Water-Reactive Aluminum Powder

by Lichen Zhang, Shuo Wang, Lixiang Zhu, Xiaodong Li, Xing Su and Meishuai Zou

Materials 2022, 15(23), 8554; https://doi.org/10.3390/ma15238554 - 1 Dec 2022

Cited by 2 | Viewed by 1667

Abstract

Aluminum powder plays important role in the field of energetic materials. However, it is often vulnerable to oxygen and water due to the high reactivity of aluminum, and it is challenging to build up uniform and passivated coating via existing means. In this [...] Read more.

Aluminum powder plays important role in the field of energetic materials. However, it is often vulnerable to oxygen and water due to the high reactivity of aluminum, and it is challenging to build up uniform and passivated coating via existing means. In this work, (Heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane (FAS-17) and glycidyl azide polymer (GAP) were used to coat the surface of high water-reactive aluminum powder (w-Al) to form inactivated w-Al@FAS-17@GAP energetic materials, via the synergy of chemical bonding and physical attraction. Thermal reaction tests showed that the exothermic enthalpy of w-Al@FAS-17@GAP was 5.26 times that of w-Al. Ignition tests showed that w-Al@FAS-17@GAP burnt violently at 760 °C, while w-Al could not be ignited even at 950 °C. In addition, the combined coating of FAS-17 and GAP could effectively improve the hydrophobicity and long-term stability of w-Al, which helped to overcome the poor compatibility of w-Al with explosive components. Our work not only displayed an effective routine to synthesize O₂/H₂O proof Al energetic materials, but also pointed out a synergistically chemical and physical strategy for constructing intact high-performance surfaces. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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10 pages, 5098 KiB

Open AccessArticle

Effect of Nitrogen Doping on Tribological Properties of Ta₂O₅ Coatings Deposited by RF Magnetron Sputtering

by Rui Chao, Haichao Cai, Hang Li and Yujun Xue

Materials 2022, 15(23), 8291; https://doi.org/10.3390/ma15238291 - 22 Nov 2022

Cited by 1 | Viewed by 1394

Abstract

Ta₂O₅ was deposited on quartz glass and Si substrates as a protective coating. The inherent RF magnetron sputtering power of 140 W was maintained during the deposition process. During the deposition process, amounts of 5%, 10%, and 15% of N [...] Read more.

Ta₂O₅ was deposited on quartz glass and Si substrates as a protective coating. The inherent RF magnetron sputtering power of 140 W was maintained during the deposition process. During the deposition process, amounts of 5%, 10%, and 15% of N₂ were injected, and the total sputtering gas (N₂+Ar) flow was kept at 40 sccm. The microstructure and surface morphology of the coatings were characterized, and the friction and wear experiments of the coatings were carried out. The results show that the coatings’ surface is smooth and the main chemical compositions are Ta, O, and N. The maximum average roughness of the coatings was prepared by pure argon sputtering. It is proved that the introduction of N₂ reduces the surface roughness of the coatings and increases the surface hardness and elastic modulus of the coatings. Adhesive wear and brittle fracture are the two main wear forms of coatings. The wear debris is mainly composed of columnar particles and a flake structure. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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12 pages, 4275 KiB

Open AccessArticle

The Electronic Structure and Optical Properties of CdGeAs₂ Crystal: A DFT and HSE06 Study

by Suqin Xue, Jing Ning, Bohang Zhang, Qiao Wu, Fuchun Zhang and Weibin Zhang

Coatings 2022, 12(11), 1778; https://doi.org/10.3390/coatings12111778 - 21 Nov 2022

Cited by 1 | Viewed by 2064

Abstract

The electronic structural and optical properties of CdGeAs₂ crystals are calculated by using the Perdew–Burke–Ernzerhof (PBE) functional within generalized gradient approximation (GGA) and the Heyd–Scuseria–Ernzerhof (HSE06) functional. The results show that CdGeAs₂ is an optical crystal with a direct bandgap of [...] Read more.

The electronic structural and optical properties of CdGeAs₂ crystals are calculated by using the Perdew–Burke–Ernzerhof (PBE) functional within generalized gradient approximation (GGA) and the Heyd–Scuseria–Ernzerhof (HSE06) functional. The results show that CdGeAs₂ is an optical crystal with a direct bandgap of 0.71 eV by using the HSE06 functional method, which is closer to the experimental value. The Mulliken population and differential charge density analysis indicate that the Ge–As and Cd–As bonds have covalent properties, and that the covalent bond of Cd–As is visibly stronger than that of the Ge–As bond. The optical properties show that the CdGeAs₂ crystal has strong absorption and reflection in the ultraviolet region and strong transmittance in the infrared region. The average static refractive index of CdGeAs₂ is 2.96, and the static birefractive index is 0.08. The results show that CdGeAs₂ is an excellent optical material of potential applications in the middle and far infrared. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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13 pages, 2673 KiB

Open AccessArticle

Individual Layer Thickness Dependence of Microstructure and Mechanical Properties of Magnetron Sputtering Mo-W-Doped Ni/Ni₃Al Multilayers

by Chao Zhang, Lijun Shao, Yuming Dai, Duo Li and Yuan Chen

Coatings 2022, 12(11), 1616; https://doi.org/10.3390/coatings12111616 - 24 Oct 2022

Viewed by 1589

Abstract

The mechanical properties of nanocrystalline pure Ni films are degraded due to grain coarsening with exposure for a long time in ambient. In order to further improve the mechanical properties of Ni-based thin films, as-sputtered Mo-W co-doped Ni/Ni₃Al multilayered structures were [...] Read more.

The mechanical properties of nanocrystalline pure Ni films are degraded due to grain coarsening with exposure for a long time in ambient. In order to further improve the mechanical properties of Ni-based thin films, as-sputtered Mo-W co-doped Ni/Ni₃Al multilayered structures were constructed. When the individual layer thickness (h) is lower than 40 nm, both the average grain sizes and the crystallinity degrees are degraded, showing a tendency for the formation of the amorphous phase. With h = 40 nm, nano-twins were observed as (111) twining interfaces for the multilayers due to the reduction of the stacking fault energy by the co-doping of Mo-W, whereas the nucleation and growth of the nano-twins were limited, without observations for the Mo-W co-doped Ni/Ni₃Al multilayer with h = 10 nm. The hardness of the multilayers was enhanced, and the elastic modulus was reduced at a lower h, owing to the grain refinements and layer interface barriers for strengthening, and the existence of the amorphous phase with the inferior modulus, respectively. The resistance against the fracture was enhanced due to toughening by the lamellar structure for the Mo-W doped Ni/Ni₃Al multilayer at h ≤ 40 nm. Comprehensively, the Mo-W-doped Ni/Ni₃Al multilayer with 10 nm displays a superior mechanical performance. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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31 pages, 14989 KiB

Open AccessArticle

Analysis on the Performance of Micro and Nano Molybdenum Di-Sulphide Powder Suspended Dielectric in the Electrical Discharge Machining Process—A Comparison

by Rajesh J. V. and Giridharan Abimannan

Nanomaterials 2022, 12(20), 3587; https://doi.org/10.3390/nano12203587 - 13 Oct 2022

Cited by 3 | Viewed by 2049

Abstract

The significance of suspending molybdenum di-sulphide powder particles of two distinct mean size viz. Φ40 μm and Φ90 nm into the dielectric of electrical discharge machining is analysed. Crater geometry, surface crack density, skewness, kurtosis and chemical alteration of machined surfaces are considered [...] Read more.

The significance of suspending molybdenum di-sulphide powder particles of two distinct mean size viz. Φ40 μm and Φ90 nm into the dielectric of electrical discharge machining is analysed. Crater geometry, surface crack density, skewness, kurtosis and chemical alteration of machined surfaces are considered as outcome measures. A numerical model using finite element analysis is developed to forecast crater geometry. To validate the proposed model, experiments are conducted by varying input parameters such as discharge duration, peak current, and gap voltage. In comparison with the experimental results, the proposed model predicts diameter of crater with an error of 3.34%, 7.32% and 2.76% for discharge duration, peak current and gap voltage respectively for Φ40 μm powder; similarly, 0.19%, 3.65% and 2.78% for Φ90 nm powder. Scanning electron microscope images, 2D roughness profiles and X-ray diffraction profiles are used to assess the partial discharge phenomena, surface crack density, skewness, kurtosis and chemical alteration of the machined surface. For all parameter settings, the Φ90 nm produced surfaces with lessened micro-cracks compared to Φ40 μm. The Φ90 nm creates surfaces with negative skewness and kurtosis less than 3. The deposition of MoS₂ powder particle on the machined surface is revealed through X-ray diffraction analysis. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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20 pages, 12317 KiB

Open AccessArticle

Effect of Surface Pre-Treatment on the Adhesion between HiPIMS Thick Cu:CuCN_x Coating and WC-Co Shim

by Md Masud-Ur Rashid, Robert Tomkowski and Andreas Archenti

Coatings 2022, 12(10), 1484; https://doi.org/10.3390/coatings12101484 - 6 Oct 2022

Cited by 7 | Viewed by 2640

Abstract

High-power impulse magnetron-sputtering thick metal/carbon–nitride-doped metal-matrix multilayer nano-composite coating can be applied to cutting-tool holder components to improve cutting insert’s life. One of the challenges of such an add-on solution is the poor adhesion between the thick coating and the hard alloy substrate, [...] Read more.

High-power impulse magnetron-sputtering thick metal/carbon–nitride-doped metal-matrix multilayer nano-composite coating can be applied to cutting-tool holder components to improve cutting insert’s life. One of the challenges of such an add-on solution is the poor adhesion between the thick coating and the hard alloy substrate, such as WC-Co shim. This work presents a study on WC-Co substrate surface preparation methods for HiPIMS coating and its adhesion improvement. Three mechanical surface pretreatment methods were investigated: machining (grinding), diamond polishing, and grit blasting. White-light interferometry was used for substrate surface texture measurement before and after pretreatment. It was demonstrated that, compared to machining and diamond polishing, grit blasting can significantly improve the interface adhesion between the ~200 µm-thick Cu:CuCN_x coating and WC-Co shim. Grit blasting was also found to be beneficial for improving the cutting insert’s life in the external turning process. In turning tests, the coating lifetime for grit-blasted shim was more than 90 min, whereas the coating lifetimes for machined shim (conventional shim) and diamond-polished shim were ~85 min and ~70 min, respectively. Further, by comparing the HiPIMS gradient chromium pre-layer between the coating and substrate for the different shims, the study also explained that the quasi-isotropic surface texture of grit-blasted shim is more advantageous for coating–substrate interface adhesion. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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18 pages, 6784 KiB

Open AccessArticle

The Effect of the Displacement Amplitude on the Fretting Wear of GCr15 Steel with a TiC Coating

by Xiaochu Liu, Sen He, Zhuan Zhao, Xincheng Xie, Jinrui Xiao and Zhongwei Liang

Materials 2022, 15(19), 6628; https://doi.org/10.3390/ma15196628 - 24 Sep 2022

Cited by 2 | Viewed by 1666

Abstract

In the present paper, the effect of mechanical ball milling time on the fretting wear of GCr15 steel balls at different displacement amplitudes is investigated. TiC powder coating was fabricated on the surface of GCr15 steel balls using various process times, and the [...] Read more.

In the present paper, the effect of mechanical ball milling time on the fretting wear of GCr15 steel balls at different displacement amplitudes is investigated. TiC powder coating was fabricated on the surface of GCr15 steel balls using various process times, and the fretting wear tests were conducted on an AISI 52100 steel disk with the applied force of 80 N. Additionally, various displacement amplitudes (10 μm, 20 μm, and 60 μm) were selected. Specimen attributes and wear scars were characterized using an inverted metallographic microscope, a microhardness tester, an X-ray diffractometry analyzer, a white light interferometer, and a scanning electron microscope. The results showed that thick and continuous coatings could be obtained at the milling time of 18 h. The specimens processed for a longer milling time demonstrated better fretting wear resistance, which we attribute to higher microhardness of the surface layer. The coefficient of friction and wear volume of specimens at each different displacement amplitude significantly decreased with increasing milling time. As the displacement amplitude increased, the three fretting states were: partial slip coordinated by elastic deformation; partial slip state coordinated by plastic deformation; and gross slip condition. Our observations indicate that mechanical ball milling could be an efficient approach to improve the fretting wear resistance of GCr15 steel balls. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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15 pages, 5032 KiB

Open AccessArticle

Modification of Polymeric Surfaces with Ultrashort Laser Pulses for the Selective Deposition of Homogeneous Metallic Conductive Layers

by Michael Seiler, Andreas Knauft, Jann Jelto Gruben, Samson Frank, Andrea Barz, Jens Bliedtner and Andrés Fabián Lasagni

Materials 2022, 15(19), 6572; https://doi.org/10.3390/ma15196572 - 22 Sep 2022

Cited by 2 | Viewed by 2065

Abstract

In recent years, the demand for highly integrated and lightweight components has been rising sharply, especially in plastics processing. One strategy for weight-saving solutions is the development of conductive tracks and layouts directly on the polymer housing parts in order to be able [...] Read more.

In recent years, the demand for highly integrated and lightweight components has been rising sharply, especially in plastics processing. One strategy for weight-saving solutions is the development of conductive tracks and layouts directly on the polymer housing parts in order to be able to dispense with the system integration of additional printed circuit boards (PCB). This can be conducted very advantageously and flexibly with laser-based processes for functionalizing polymer surfaces. In this work, a three-step laser-based process for subsequent selective metallization is presented. Conventional injection molded components without special additives serve as the initial substrate. The Laser-Based Selective Activation (LSA) uses picosecond laser pulses to activate the plastic surface to subsequently deposit palladium. The focus is on determining the amount of deposited palladium in correlation to the laser and scan parameters. For the first time, the dependence of the metallization result on the accumulated laser fluence (F_acc) is described. The treated polymer parts are characterized using optical and scanning electron microscopy as well as a contact-type profilometer. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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8 pages, 2136 KiB

Open AccessArticle

Sol–Gel-Derived Ni₃Al Coating on Nickel Alloy for Oxidation Resistance in Supercritical Water Environments

by Yuelong Pan, Zhidong Zhang, Daoyuan Wang, Hao Guo, Qiwu Shi and Tiecheng Lu

Materials 2022, 15(19), 6566; https://doi.org/10.3390/ma15196566 - 22 Sep 2022

Cited by 1 | Viewed by 1732

Abstract

Although nickel-based alloys are widely used in industries due to their oxidation and corrosion resistance, the pursuit of better performance in harsh environments is still a great challenge. In this work, we developed a sol–gel method to synthesize Ni₃Al coating on [...] Read more.

Although nickel-based alloys are widely used in industries due to their oxidation and corrosion resistance, the pursuit of better performance in harsh environments is still a great challenge. In this work, we developed a sol–gel method to synthesize Ni₃Al coating on a nickel alloy, assisted by a post-annealing process, and investigated the oxidation-resistant performance. The coating thickness can be controlled by designing the deposition times, which keep the pure Ni₃Al phase stable. In addition, the surface morphologies indicate that the coating is compact without obvious voids or cracks. Furthermore, the oxidation-resistant property of the coating was investigated by carrying out a supercritical water oxidation experiment. The crystalline structure and surface morphology of the samples before and after 72-h oxidation demonstrated the superior oxidation resistance of the coating. This work provides a convenient method to fabricate an oxidation-resistant coating on a nickel-based alloy, which would be significant for prolonging the service life of vessels under oxidation conditions, especially for supercritical water reactions. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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20 pages, 5213 KiB

Open AccessArticle

Effect of Diamond Burnishing on Fatigue Behaviour of AISI 304 Chromium-Nickel Austenitic Stainless Steel

by Jordan Maximov, Galya Duncheva, Angel Anchev, Vladimir Dunchev and Yaroslav Argirov

Materials 2022, 15(14), 4768; https://doi.org/10.3390/ma15144768 - 7 Jul 2022

Cited by 13 | Viewed by 1760

Abstract

The disadvantages of widely used austenitic stainless steels are their low hardness and relatively low fatigue strength. Conventional chemical-thermal surface treatments are unsuitable for these steels since they create conditions for inter-granular corrosion. An effective alternative is a low-temperature surface treatment, creating an [...] Read more.

The disadvantages of widely used austenitic stainless steels are their low hardness and relatively low fatigue strength. Conventional chemical-thermal surface treatments are unsuitable for these steels since they create conditions for inter-granular corrosion. An effective alternative is a low-temperature surface treatment, creating an S-phase within the surface layer, but it has a high cost/quality ratio. Austenitic steels can increase their surface micro-hardness and fatigue strength via surface cold working. When the goal is to increase the rotating bending fatigue strength of austenitic chromium-nickel steels, and the requirements for significant wear resistance are not paramount, diamond burnishing (DB) has significant potential to increase the fatigue strength and, based on the cost/quality ratio, can successfully compete with low-temperature chemical-thermal treatments. The main objective of this study is to establish the effect of DB on the rotating fatigue strength of AISI 304 L chromium-nickel austenitic steel. The influence of DB parameters on the surface integrity (SI) characteristics was studied. Optimal DB parameters under minimum roughness and maximum micro-hardness criteria were obtained. Rotating bending fatigue tests of the diamond burnished (in a different manner) and untreated specimens were performed. DB implemented via parameters providing maximum micro-hardness increased fatigue limit by 38% compared to untreated specimens. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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21 pages, 2216 KiB

Open AccessReview

Review on the Recent Development of Fatty Hydrazide as Corrosion Inhibitor in Acidic Medium: Experimental and Theoretical Approaches

by Almila Hassan, Mohd Sofi Numin, Khairulazhar Jumbri, Kok Eng Kee and Noorazlenawati Borhan

Metals 2022, 12(7), 1058; https://doi.org/10.3390/met12071058 - 21 Jun 2022

Cited by 7 | Viewed by 2319

Abstract

In recent years, numerous research work has been conducted in order to find the most practical and cost-effective solution for corrosion issues in the oil and gas industry. Several studies have revealed that fatty hydrazide derivatives are the most suitable corrosion inhibitor for [...] Read more.

In recent years, numerous research work has been conducted in order to find the most practical and cost-effective solution for corrosion issues in the oil and gas industry. Several studies have revealed that fatty hydrazide derivatives are the most suitable corrosion inhibitor for the application in the said industry. These compounds can also act as effective corrosion inhibitors in acidic medium with inhibition efficiency greater than 95%. This review summarizes and discusses the recent corrosion inhibitor development in acidic media from 2017 until 2021, focusing on fatty hydrazide derivatives. The significant findings and mechanisms of inhibition have been elucidated. In addition, intake on the computer simulation studies of fatty hydrazide inhibition properties is also included in this review. Finally, some suggestions for future research on corrosion inhibitors have been recommended. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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12 pages, 2802 KiB

Open AccessEditor’s ChoiceArticle

Artificial Synapse Consisted of TiSbTe/SiC_x:H Memristor with Ultra-high Uniformity for Neuromorphic Computing

by Liangliang Chen, Zhongyuan Ma, Kangmin Leng, Tong Chen, Hongsheng Hu, Yang Yang, Wei Li, Jun Xu, Ling Xu and Kunji Chen

Nanomaterials 2022, 12(12), 2110; https://doi.org/10.3390/nano12122110 - 19 Jun 2022

Cited by 3 | Viewed by 2339

Abstract

To enable a-SiC_x:H-based memristors to be integrated into brain-inspired chips, and to efficiently deal with the massive and diverse data, high switching uniformity of the a-SiC_0.11:H memristor is urgently needed. In this study, we introduced a TiSbTe layer into [...] Read more.

To enable a-SiC_x:H-based memristors to be integrated into brain-inspired chips, and to efficiently deal with the massive and diverse data, high switching uniformity of the a-SiC_0.11:H memristor is urgently needed. In this study, we introduced a TiSbTe layer into an a-SiC_0.11:H memristor, and successfully observed the ultra-high uniformity of the TiSbTe/a-SiC_0.11:H memristor device. Compared with the a-SiC_0.11:H memristor, the cycle-to-cycle coefficient of variation in the high resistance state and the low resistance state of TiSbTe/a-SiC_0.11:H memristors was reduced by 92.5% and 66.4%, respectively. Moreover, the device-to-device coefficient of variation in the high resistance state and the low resistance state of TiSbTe/a-SiC_0.11:H memristors decreased by 93.6% and 86.3%, respectively. A high-resolution transmission electron microscope revealed that a permanent TiSbTe nanocrystalline conductive nanofilament was formed in the TiSbTe layer during the DC sweeping process. The localized electric field of the TiSbTe nanocrystalline was beneficial for confining the position of the conductive filaments in the a-SiC_0.11:H film, which contributed to improving the uniformity of the device. The temperature-dependent I-V characteristic further confirmed that the bridge and rupture of the Si dangling bond nanopathway was responsible for the resistive switching of the TiSbTe/a-SiC_0.11:H device. The ultra-high uniformity of the TiSbTe/a-SiC_0.11:H device ensured the successful implementation of biosynaptic functions such as spike-duration-dependent plasticity, long-term potentiation, long-term depression, and spike-timing-dependent plasticity. Furthermore, visual learning capability could be simulated through changing the conductance of the TiSbTe/a-SiC_0.11:H device. Our discovery of the ultra-high uniformity of TiSbTe/a-SiC_0.11:H memristor devices provides an avenue for their integration into the next generation of AI chips. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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15 pages, 5044 KiB

Open AccessArticle

Deposition of Aluminide Coatings onto AISI 304L Steel for High Temperature Applications

by Zubia Anwer, Muhammad Tufail and Ali Dad Chandio

Materials 2022, 15(12), 4184; https://doi.org/10.3390/ma15124184 - 13 Jun 2022

Cited by 1 | Viewed by 2085

Abstract

The nickel aluminides are commonly employed as a bond coat material in thermal barrier coating systems for the components of aeroengines operated at very high temperatures. However, their lifetime is limited due to several factors, such as outward diffusion of substrate elements, surface [...] Read more.

The nickel aluminides are commonly employed as a bond coat material in thermal barrier coating systems for the components of aeroengines operated at very high temperatures. However, their lifetime is limited due to several factors, such as outward diffusion of substrate elements, surface roughness at high temperatures, morphological changes of the oxide layer, etc. For this reason, inter-diffusion migrations were studied in the presence and absence of nickel coating. In addition, a hot corrosion study was also carried out. Thus, on one set of substrates, nickel electrodeposition was carried out, followed by a high activity pack aluminizing process, while another set of substrates were directly aluminized. The microstructural, mechanical, and oxidation properties were examined using different characterization techniques, such as SEM-EDS, optical microscopy, XRD, optical emission spectroscopy, surface roughness (Ra), and adhesion tests. In addition, the variable oxidation temperatures were employed to better understand their influence on the roughness, degree of spallation (DoS), and morphology. The results show that AISI 304L substrates do not respond to aluminizing treatment, i.e., no aluminide coating was formed; rather, a nearly pure aluminum (or alloy) was observed on the substrate. On the contrary, successful formation of an aluminide coating was observed on the nickel-electrodeposited substrates. In particular, a minimum amount of migrations were noted, which is attributed to nickel coating. Moreover, the scratch test at 10 N load revealed neither cracking nor peeling off, thereby indicating good adhesion of the aluminide coating before oxidation. The as-aluminized samples were oxidized between 700 °C to 1100 °C in air for 8 h each. The degree of spallation showed an incremental trend as temperatures increased. Likewise, oxide morphologies showed temperature dependence. On the other hand, average surface roughness (from Ra = 2.3 µm to 5.8 µm) was also increased as temperatures rose. Likewise, the mass gain showed linearity as temperatures increased during oxidation. The hot corrosion responses of electrodeposited-aluminized samples were superior among all specimens. An extensive discussion is presented based on the observations noted above. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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16 pages, 6080 KiB

Open AccessArticle

Properties of SS304 Modified by Nickel–Cobalt Alloy Coating with Cauliflower-Shaped Micro/Nano Structures in Simulated PEMFC Cathode Environment

by Junji Xuan, Yueren Liu, Likun Xu, Yonglei Xin, Lili Xue and Li Li

Nanomaterials 2022, 12(12), 1976; https://doi.org/10.3390/nano12121976 - 9 Jun 2022

Cited by 9 | Viewed by 2426

Abstract

This study presents the corrosion behavior and surface properties of SS304 modified by electrodeposited nickel–cobalt (Ni–Co) alloy coating with cauliflower-shaped micro/nano structures (Ni–Co/SS304) in the simulated PEMFC cathodic environment. The hydrophobicity of the as-prepared Ni–Co alloy coating can be improved simply by low-temperature [...] Read more.

This study presents the corrosion behavior and surface properties of SS304 modified by electrodeposited nickel–cobalt (Ni–Co) alloy coating with cauliflower-shaped micro/nano structures (Ni–Co/SS304) in the simulated PEMFC cathodic environment. The hydrophobicity of the as-prepared Ni–Co alloy coating can be improved simply by low-temperature annealing. The morphology and composition of the Ni–Co/SS304 were analyzed and characterized by SEM, EDS, XRD, and XPS. The polarization, wettability, and ICR tests were respectively conducted to systemically evaluate the performance of Ni–Co/SS304 in the simulated PEMFC cathode environment. As revealed by the results, the Ni–Co/SS304 can maintain its hydrophobicity under hot-water droplets as high as 80 °C and demonstrates higher conductivity than the bare SS304 substrate before and after polarization (0.6 V vs. SCE, 5 h), which is of great significance to improve the surface hydrophobicity and conductivity of bipolar plates. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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10 pages, 68906 KiB

Open AccessArticle

Effect of Humidity on Metallizing on Polyphenylene Sulfide (PPS) with Atmospheric UV Treatment

by Toshimichi Yamagishi, Tomoaki Inoue and Mitsuhiro Watanabe

Coatings 2022, 12(6), 791; https://doi.org/10.3390/coatings12060791 - 7 Jun 2022

Cited by 2 | Viewed by 2639

Abstract

Polyphenylene sulfide (PPS) is an engineering plastic; when reinforced with fillers, it exhibits high heat resistance, strength, and molding/dimensional stability. Plating on PPS without using harmful chemicals can meet the following requirements due to its excellent properties: low environmental load process, lightweight metal [...] Read more.

Polyphenylene sulfide (PPS) is an engineering plastic; when reinforced with fillers, it exhibits high heat resistance, strength, and molding/dimensional stability. Plating on PPS without using harmful chemicals can meet the following requirements due to its excellent properties: low environmental load process, lightweight metal substitute materials, electromagnetic wave shielding materials, etc. This study focused on metallizing by atmospheric ultraviolet (UV) treatment of PPS. This process is generally used for the pretreatment of painting and adhesion, and it entails a small environmental load; however, the UV treatment of moist air produces various chemical species. Therefore, the humidity effect during metallizing via atmospheric UV treatment was investigated, revealing its influence on the adhesion strength of the resulting metal film. In a dry environment, a metal film with strong adhesion can be formed on PPS, and UV treatment under such conditions can maintain the structure of the PPS surface. In contrast, a weak layer was generated under wet conditions, reducing the adhesion strength between the metal film and PPS. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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16 pages, 7221 KiB

Open AccessArticle

Effect of Cerium Tartrate on the Corrosion Resistance of Epoxy Coating on Aluminum Alloy and Its Mechanism

by Xueping Chen, Jianhua Tang, Han Wei, Hanlu Zhang, Yuming Tang, Xuhui Zhao and Yu Zuo

Coatings 2022, 12(6), 785; https://doi.org/10.3390/coatings12060785 - 7 Jun 2022

Cited by 6 | Viewed by 2173

Abstract

The inhibition effect and mechanism of cerium tartrate (CeTar) as a pigment in epoxy coating on AA2024-T3 aluminum alloy in 3.5% NaCl solution were studied. Two kinds of coatings were applied on the substrate, including a single-layer epoxy coating with CeTar distributed uniformly [...] Read more.

The inhibition effect and mechanism of cerium tartrate (CeTar) as a pigment in epoxy coating on AA2024-T3 aluminum alloy in 3.5% NaCl solution were studied. Two kinds of coatings were applied on the substrate, including a single-layer epoxy coating with CeTar distributed uniformly and a double-layer coating composed of an inner layer doped with CeTar and an outer layer with no CeTar. The protective performances of the coatings were assessed by a Machu test and an Electrochemical impedance spectroscopy (EIS) technique. The corrosion inhibition mechanism of CeTar in the coating was analyzed with X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS) and Fourier transform spectroscopy (FTIR). The results show that the addition of CeTar can evidently improve the protective performance of the epoxy coating for a long time (>520 d). This might have relationship with the modification effect on the epoxy coating by cerium salts, and also may be due to the synergistic inhibitory effect by tartrate group and cerium ions on the alloy substrate after their continuous releasing to the coating/alloy interface and forming of a protective film. The double-layer coating provides similar protective properties to the single-layer coating. This suggested that creating a protective film on the aluminum alloy substrate could result in a greater contribution to improving the protection performance of the coating. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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16 pages, 6461 KiB

Open AccessArticle

Research on the Effect of Tip Surface Coatings on High-Speed Spindles’ Noise

by Hechun Yu, Wenchao Li, Jin Wang, Suxiang Zhang, Xiucheng Cao, Renzong Wang, Guoqing Zhang and Xiaolong Yin

Coatings 2022, 12(6), 783; https://doi.org/10.3390/coatings12060783 - 6 Jun 2022

Cited by 1 | Viewed by 1901

Abstract

The contact interface between the stator and the rotor tip of the spindle could be destructed when the spindle is rotating continually at high speed, which will cause strong noise and severe vibration. In order to reduce the sound pressure level of the [...] Read more.

The contact interface between the stator and the rotor tip of the spindle could be destructed when the spindle is rotating continually at high speed, which will cause strong noise and severe vibration. In order to reduce the sound pressure level of the noise generated by the rotating spindle, three different coating materials, that is, Al-Ti-Cr-C, Ti-C and DLC, were applied to the rotor tip surface of the spindle. The effects of the coating materials on the sound pressure levels of the rotating spindles were studied by using the treated spindles and the untreated spindles. Results showed that compared with Coating Al-Ti-Cr-C, the Coating Ti-C containing only the two main elements of Ti and C produces the smallest sound pressure level in the experiment speed range; the surface roughness of Coating DLC is smaller, but the sound pressure level of the entire spindle becomes larger than Coating Ti-C; the sound pressure level of the spindles with surface coating treatment is obviously lower than that of the spindles without coating treatment. The research results can provide basic data for the design and production of noiseless spinning spindles. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 6812 KiB

Open AccessArticle

Local Electrochemical Corrosion Properties of a Nano-SiO₂/MAO Composite Coating on an AM60B-Mg Alloy

by Xiaoyu Yang, Yu Mo, Ting Dai, Jie Zhao and Yanhong Gu

Materials 2022, 15(11), 3999; https://doi.org/10.3390/ma15113999 - 4 Jun 2022

Cited by 3 | Viewed by 2011

Abstract

In order to improve the corrosion resistance of the automotive AM60B-Mg alloy, a nano-SiO₂/MAO composite coating was prepared on the surface of the alloy. The electrochemical properties were studied in an 80 °C corrosion environment using potentiodynamic polarization tests. Local Electrochemical [...] Read more.

In order to improve the corrosion resistance of the automotive AM60B-Mg alloy, a nano-SiO₂/MAO composite coating was prepared on the surface of the alloy. The electrochemical properties were studied in an 80 °C corrosion environment using potentiodynamic polarization tests. Local Electrochemical Impedance Spectroscopy (LEIS) was used to study the corrosion mechanisms of coating defect zone. The microstructure and phase of the samples were observed by confocal laser microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Macroscopic electrochemical test results showed that the impedance of the nano-SiO₂/MAO coating was much higher than that of the MAO coating, by about 433 times. Local electrochemical test results showed that the minimum impedance of the nano-SiO₂/MAO coating was 1–2 orders of magnitude higher than the maximum impedance of the MAO coating. The defective SiO₂/MAO coating still had high corrosion resistance compared to the defective MAO coating. A physical model of local corrosion mechanisms was proposed. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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15 pages, 4228 KiB

Open AccessArticle

The Effect of Inorganic Preservatives in the Norway Spruce Wood on Its Wettability and Adhesion with PUR Glue

by Dávid Ciglian and Ladislav Reinprecht

Appl. Sci. 2022, 12(11), 5642; https://doi.org/10.3390/app12115642 - 1 Jun 2022

Cited by 5 | Viewed by 2257

Abstract

Recycled recovered wood, for example, from historic buildings, containing biocides, fire retardants or anti-weather paints is an attractive material for manufacturing composite wood panels which can be used for decoration as well as load-bearing walls with a typical patina. This paper investigates the [...] Read more.

Recycled recovered wood, for example, from historic buildings, containing biocides, fire retardants or anti-weather paints is an attractive material for manufacturing composite wood panels which can be used for decoration as well as load-bearing walls with a typical patina. This paper investigates the effect of four inorganic wood preservatives—CuSO₄·5H₂O, ZnCl₂, H₃BO₃ and (NH₄)₂SO₄—commonly used in the past, with the focus on their effect on the quality of wood bonding. The milled surfaces of Norway spruce (Picea abies Karst L.) wood were treated with 0.5, 1 and 2% aqueous solutions of these preservatives. The effect of preservatives in spruce wood was evaluated: (1) by its wettability with the drops of redistilled water, measuring the contact angles; (2) by the shear strength of the “spruce wood—polyurethane (PUR) Kestopur 1030 glue” interphases according to the standard EN 205; (3) by microscopic analysis of the “wood—PUR” interphases. The wettability of spruce wood worsened when using ZnCl₂, by a maximum of 28.2%, but on the contrary, it improved due to other preservatives mainly by using (NH₄)₂SO₄, at a maximum of 22.9%. In general, the shear strength of glued joints “wood—PUR” continually decreased with higher concentrations of all the preservatives. The most significant decrease of adhesion “wood—PUR”, by 19.8% from 10.66 MPa to 8.55 MPa, was caused by 2% ZnCl₂ used for the treatment of both spruce wood specimens in interphase with the PUR glue. On the contrary, the less significant decrease of adhesion “wood—PUR”, by 2.5%, was caused by 0.5% (NH₄)₂SO₄ applied only on one surface of the two inter-bonded spruce wood specimens. The effects of preservatives on the wood wettability and its adhesion with PUR glue were partly confirmed by microscopic analysis. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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16 pages, 14930 KiB

Open AccessArticle

Influence of Y Nano-Oxide and Its Secondary Phase on Microstructure, Mechanical Properties, and Wear Behavior of the Stainless Steel Coatings Fabricated by Plasma Transfer Arc

by Junyu Yue, Yi Sui, Lifeng Yang, Fei Lu, Weidong Chen, Xiaoyu Liu and Xiaohua Sun

Metals 2022, 12(6), 942; https://doi.org/10.3390/met12060942 - 30 May 2022

Cited by 2 | Viewed by 1800

Abstract

Rare-earth is an efficient refiner for surface modification of steel material. This study presents the synergistic influence of Y₂O₃ nanoparticles (YNPs) and Mn-oxide secondary phase on the microstructure and mechanical properties of 14CrSiMnV coating fabricated by plasma transfer arc cladding [...] Read more.

Rare-earth is an efficient refiner for surface modification of steel material. This study presents the synergistic influence of Y₂O₃ nanoparticles (YNPs) and Mn-oxide secondary phase on the microstructure and mechanical properties of 14CrSiMnV coating fabricated by plasma transfer arc cladding process. The results indicated that the residual Y accumulated with Mn, forming a secondary phase oxide particle instead of inclusions or slags during rapid cooling solidification of the coating. Due to enlarged equiaxed grains, declining long-range dendritic grains, and secondary phase strengthening, steel coatings present hybrid-type fracture mechanism, less plastic deformation, and third-body interaction. With an optimal addition of YNPs (0.4 wt.%), the mechanical properties of the steel coating are improved, as indicated by the increase of 92.0% in the tensile strength, increase of 55.6% in the elongation, increase of 11.3% in the microhardness, decrease of 22.2% in wear weight loss, and increase of 28.3% in relative wear resistance. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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17 pages, 2632 KiB

Open AccessArticle

Effect of HAc on the Metastable Pitting Corrosion of 304 SS in NaCl Solution

by Hanlu Zhang, Wenqiang Huang, Han Wei, Zilong Chen, Jingyi Cao, Yuming Tang, Xuhui Zhao and Yu Zuo

Materials 2022, 15(10), 3618; https://doi.org/10.3390/ma15103618 - 18 May 2022

Cited by 8 | Viewed by 2401

Abstract

Stainless steels (SSs) easily suffer localized corrosion damage, such as pitting corrosion, in mixed solutions of acetic acid and sodium chloride. Currently, few works have been focused on the early stages of the pitting corrosion (metastable pitting corrosion) process of SSs in a [...] Read more.

Stainless steels (SSs) easily suffer localized corrosion damage, such as pitting corrosion, in mixed solutions of acetic acid and sodium chloride. Currently, few works have been focused on the early stages of the pitting corrosion (metastable pitting corrosion) process of SSs in a chloride-HAc mixture solution. In this work, the effects of acetic acid (HAc) and its concentration on metastable pitting corrosion and the uniform corrosion of 304 SS in 0.6 mol/L NaCl solution were investigated by a slow-scanning potentiodynamic polarization test, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results show that the uniform corrosion rate of 304 SS increases after HAc addition but, with an increase in HAc concentration, the corrosion rate decreases. In the presence of HAc, the metastable pitting potential (E_m) and stable pitting potential (E_b) move negatively, but the number of metastable pits notably decreases. HAc has a promoting action on the growth rate of the metastable pits and facilitates the transition from metastable pits to stable pits. The influence of HAc is related to a decrease in solution pH and the chemical adsorption of HAc. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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12 pages, 3698 KiB

Open AccessArticle

Performance of SS304 Modified by Silver Micro/Nano-Dendrite Coating with Hot-Water Super-Repellency in Simulated PEMFC Cathode Environment

by Junji Xuan, Bingzhi Li, Likun Xu, Zhaoqi Zhang, Yonglei Xin, Lili Xue and Li Li

Nanomaterials 2022, 12(10), 1726; https://doi.org/10.3390/nano12101726 - 18 May 2022

Cited by 2 | Viewed by 1949

Abstract

In this study, an silver (Ag) plating with micro/nano-dendrite structures is prepared on the 304 stainless steel (SS304) surface by potentiostatic deposition (Ag/SS304). After being modified by n-dodecyl mercaptan (NDM) with the low surface energy, the obtained sample (NDM@Ag/SS304) exhibits stable superhydrophobicity and [...] Read more.

In this study, an silver (Ag) plating with micro/nano-dendrite structures is prepared on the 304 stainless steel (SS304) surface by potentiostatic deposition (Ag/SS304). After being modified by n-dodecyl mercaptan (NDM) with the low surface energy, the obtained sample (NDM@Ag/SS304) exhibits stable superhydrophobicity and excellent hot-water repellency. The surface morphology and composition of NDM@Ag/SS304 are analyzed by scanning electron microscope (SEM), X-ray spectrometer (EDS), X-ray diffractometer (XRD), and X-ray photoelectron spectrometer (XPS) characterization. The electrochemical measurements, tests of water contact angle (WCA), and interfacial contact resistance (ICR) are employed to systematically study the performance of the NDM@Ag/SS304 in the simulated cathode environment of proton exchange membrane fuel cell (PEMFC). The results show that the NDM@Ag/SS304 has high corrosion potential (~0.25 V) and low corrosion current density (~4.04 μA/cm²); after potentiostatic polarization (0.6 V, 5 h), the NDM@Ag/SS304 also shows high superhydrophobic stability. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 3427 KiB

Open AccessArticle

Preparation and Application of a New Two-Component Superhydrophobic Coating on Aluminum Alloy

by Chao Qiu, Shuai Liang, Meng Li, Han Cheng and Wenfeng Qin

Metals 2022, 12(5), 850; https://doi.org/10.3390/met12050850 - 16 May 2022

Cited by 1 | Viewed by 1957

Abstract

Superhydrophobic surfaces have been widely used for their corrosion resistance, self-cleaning and anti-icing characteristics. A new two-component superhydrophobic coating was prepared on aluminum alloy, and some application properties were studied. With appropriate silica, the contact angle of the two-component superhydrophobic coating can be [...] Read more.

Superhydrophobic surfaces have been widely used for their corrosion resistance, self-cleaning and anti-icing characteristics. A new two-component superhydrophobic coating was prepared on aluminum alloy, and some application properties were studied. With appropriate silica, the contact angle of the two-component superhydrophobic coating can be 164.4°, and it has good resistance to the continuous hitting of water droplets and the corrosion of acid. Even when it had been continuous impacted by acid droplets for 300 min, the contact angle of the coating was still lager than 150°. However, the coating was easily corroded by sodium hydroxide. Moreover, it can not only reduce its freezing point by more than 5 °C, but also delay the freezing of droplets on aluminum alloy by about 20 s at the temperature of −20 °C. More than that, the growth of ice or frost on it can only cause extremely minor mechanical damage to it. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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15 pages, 9391 KiB

Open AccessArticle

Preparation and Performance of Mo/Cu/Fe Multi-Layer Composite Coating with Staggered Spatial Structure by Electro-Explosive Spraying Technology

by Kun Huang, Qiuzhi Song, Pengwan Chen and Ye Liu

Materials 2022, 15(10), 3552; https://doi.org/10.3390/ma15103552 - 16 May 2022

Cited by 4 | Viewed by 1828

Abstract

In the present study, electro-explosive spraying technology was used to prepare a multi-layer composite coating with a staggered spatial structure on a 45 steel substrate, and the mechanical properties and wear behavior of the coating were studied. The composite coating was prepared by [...] Read more.

In the present study, electro-explosive spraying technology was used to prepare a multi-layer composite coating with a staggered spatial structure on a 45 steel substrate, and the mechanical properties and wear behavior of the coating were studied. The composite coating was prepared by spraying Mo as the bonding layer, then spraying high-carbon steel and aluminum bronze alternately as a functional coating. The cross-sectional morphology, surface morphology and the properties of the coating were analyzed with a scanning electron microscope (SEM), energy dispersive spectrometer (EDS), electron backscattered diffraction (EBSD) and a 3D profilometer. The bonding strength, friction and wear resistance of the coating were studied by the bonding strength experiment and by the friction and wear experiment. The results showed that it is feasible to prepare a composite coating with a sponge-like spatial structure with electro-explosive technology. There was metallurgical bonding as well as mechanical bonding between the adjacent coating layers. The composite coating had the advantages of uniform thickness, high compactness, high bonding strength and good wear resistance. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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6 pages, 1683 KiB

Open AccessEditor’s ChoiceCommunication

Fast Filling of Microvia by Pre-Settling Particles and Following Cu Electroplating

by Ganglong Li, Zhiyi Li, Junjie Li and Houya Wu

Nanomaterials 2022, 12(10), 1699; https://doi.org/10.3390/nano12101699 - 16 May 2022

Viewed by 2063

Abstract

Microvia interconnectors are a critical element of 3D packaging technology, as they provide the shortest interconnection path between stacked chips. However, low efficiency of microvia filling is a long-standing problem. This study proposed a two-step method to enhance the electroplating filling efficiency by [...] Read more.

Microvia interconnectors are a critical element of 3D packaging technology, as they provide the shortest interconnection path between stacked chips. However, low efficiency of microvia filling is a long-standing problem. This study proposed a two-step method to enhance the electroplating filling efficiency by pre-setting metal particles in microvias and later electroplating the Cu to fill the gaps among the pre-settled particles. Since these particles occupy a certain volume in the microvia, less electroplating Cu is needed for microvia filling, leading to a shorter electroplating period. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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9 pages, 2198 KiB

Open AccessArticle

Investigation of a Macromolecular Additive on the Decrease of the Aluminum Horizontal Etching Rate in the Wet Etching Process

by Jingxiu Ding, Ruipeng Zhang, Yuchun Li, David Wei Zhang and Hongliang Lu

Metals 2022, 12(5), 813; https://doi.org/10.3390/met12050813 - 8 May 2022

Cited by 1 | Viewed by 2559

Abstract

The effect of a macromolecular additive on the etching rate of aluminum (Al) horizontal etching in the wet process was investigated in this work. The horizontal etching in the Al wet etching process became more evident as the film Al becomes thicker. The [...] Read more.

The effect of a macromolecular additive on the etching rate of aluminum (Al) horizontal etching in the wet process was investigated in this work. The horizontal etching in the Al wet etching process became more evident as the film Al becomes thicker. The proposed macromolecule additive, including polyethylene-polypropylene glycol, was added into the Al etchant solution to reduce the Al horizontal etching rate (ER). The undercut problem during metal patterning can then be improved. By using this method, the Al horizontal ER was reduced from 2.0 to 0.9 μm per minute and the selection ratio between the horizontal and vertical ER was effectively improved from 3 to 1.3 times. As well, a hypothesis of physical mechanism for the improvement was proposed. The dispersed particles from the additive emulsion inhibited the transport and exchange of liquid in a horizontal direction. This work provides an alternative reference to improve the selection ratio performance in the metal wet etching process compared with that when using traditional method. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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12 pages, 2393 KiB

Open AccessArticle

Formation and Performance of Diamond (111)/Cu Interface from First-Principles Calculation

by Yongsheng Zhao, Fengyun Yan and Yi An

Coatings 2022, 12(5), 619; https://doi.org/10.3390/coatings12050619 - 2 May 2022

Cited by 10 | Viewed by 2686

Abstract

The interface formation and properties of composite materials are very important for the preparation of composite materials, and the bonding state and charge transfer between atoms in the interface have a particularly significant effect on the interface formation. In this work, the first-principles [...] Read more.

The interface formation and properties of composite materials are very important for the preparation of composite materials, and the bonding state and charge transfer between atoms in the interface have a particularly significant effect on the interface formation. In this work, the first-principles calculation method was used to study the adsorption behavior and molecular dynamics of copper atoms on the (111) surface of H-terminated diamond, and the adsorption energy and adhesion work of Cu atoms were calculated. The results show that the adsorption of copper atoms is not sensitive to the diamond (111) surface, the adsorption work is very small at the four high symmetry positions, and the adhesion work is the largest at the T4 position and is 0.6106 J/m². Furthermore, according to the electron localization function (ELF) analysis, there is no compound formation between Cu and H atoms; only a small amount of charge transfer exists, which belongs to physical adsorption. The diamond–copper interface formed by the growth of adsorption sites is a metastable structure without energy stability. This work provides an important theoretical reference for understanding the formation mechanism of copper-based diamond composites. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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13 pages, 4482 KiB

Open AccessArticle

Microstructural Transformation and High-Temperature Aluminum Corrosion Properties of Co-Based Alloy Coating Prepared by Laser Cladding

by Rui Liu, Mengyu Zhang, Jiacheng Yu, Qifan Yang and Shiyou Gao

Coatings 2022, 12(5), 603; https://doi.org/10.3390/coatings12050603 - 28 Apr 2022

Cited by 7 | Viewed by 2219

Abstract

A Co-based alloy coating was deposited on H13 steel substrate via pulsed Nd:YAG laser and the corrosion resistance to and mechanism of corrosion in molten aluminum were explored. The results showed that the coating was mainly composed of γ-Co dendrite and M₂₃ [...] Read more.

A Co-based alloy coating was deposited on H13 steel substrate via pulsed Nd:YAG laser and the corrosion resistance to and mechanism of corrosion in molten aluminum were explored. The results showed that the coating was mainly composed of γ-Co dendrite and M₂₃C₆ precipitation. The average hardness in the cladding layer was 732.6 HV_0.5, which was 3.55 times greater than that of the H13 substrate. During the molten aluminum corrosion test, the surface of the Co-based alloy coating was immersed for 4, 8, 16 and 24 h at 700 °C. The corrosion rate decreased with increases in aluminum erosion time. It was observed that there were two intermediate layers between the coating and the liquid Al, with (Co, Fe, Cr)₂Al₉ intermetallic compounds (IMCs) layer near the coating side and the (Fe, Cr)₄Al₁₃ and (Co, Fe, Cr)₂Al₅ intermetallic compounds (IMCs) layer near the Al solidification side. After 24 h of static corrosion, the Co-based alloy coating could still maintain its integrity to protect the substrate. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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12 pages, 4227 KiB

Open AccessArticle

Surface Uniformity of Wafer-Scale 4H-SiC Epitaxial Layers Grown under Various Epitaxial Conditions

by Siqi Zhao, Jiulong Wang, Guoguo Yan, Zhanwei Shen, Wanshun Zhao, Lei Wang and Xingfang Liu

Coatings 2022, 12(5), 597; https://doi.org/10.3390/coatings12050597 - 27 Apr 2022

Cited by 6 | Viewed by 3709

Abstract

Wide band gap semiconductor 4H-SiC is currently widely used in the manufacture of high-frequency and high-voltage power devices. The size of commercial 4H-SiC wafers is increasing, from 4 inches to 6 inches. Surface roughness, as one of the parameters reflecting the quality of [...] Read more.

Wide band gap semiconductor 4H-SiC is currently widely used in the manufacture of high-frequency and high-voltage power devices. The size of commercial 4H-SiC wafers is increasing, from 4 inches to 6 inches. Surface roughness, as one of the parameters reflecting the quality of epitaxial wafers, is closely related to the performance of power devices. Most studies on the uniformity of epitaxial layers did not focus on RMS; however, the uniformity of epitaxial surface roughness also affects the device yield. In this paper, the root mean square roughness (RMS) and uniformity (σ) of epitaxial wafers are investigated as a function of epitaxy conditions, including C/Si ratio, growth temperature, and Si/H ratio. It was found that the best values of RMS and σ were obtained with C/Si ratio = 1 in the experimental range. Growth temperature had opposite effects on RMS and σ, with better RMS uniformity obtained at lower growth temperatures. An insignificant effect on RMS and σ has been found with the Si/H ratio changes in the experimental range. We hope that our experiments can play a certain role in promoting the improvement of the surface roughness of wafer-scale 4H-SiC epitaxial layers. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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15 pages, 9277 KiB

Open AccessArticle

A Comparative Study on Mechanical and Corrosion Behaviours of α/(α + β) Mg-Li Alloys Subjected to Ultrasonic Nanocrystal Surface Modification

by Yun Zou, Shuhao Liu, Qilong Wang and Yang Li

Metals 2022, 12(4), 681; https://doi.org/10.3390/met12040681 - 15 Apr 2022

Cited by 6 | Viewed by 2461

Abstract

Ultrasonic nanocrystal surface modification (UNSM) was applied to hot-rolled Mg-Li alloys (LAE361 and LA106). The microstructure, mechanical properties, deformation mechanisms, and corrosion resistance properties of these alloys after UNSM treatment were systematically studied. Significant improvement in surface hardness and decrease in surface roughness [...] Read more.

Ultrasonic nanocrystal surface modification (UNSM) was applied to hot-rolled Mg-Li alloys (LAE361 and LA106). The microstructure, mechanical properties, deformation mechanisms, and corrosion resistance properties of these alloys after UNSM treatment were systematically studied. Significant improvement in surface hardness and decrease in surface roughness were achieved by UNSM treatment. Meanwhile, the basal texture intensity of the Mg-Li alloys reduced significantly, and several deformation twins appeared on the surface layer. The α phase of the surface layer underwent twin deformation and basal plane slip. The fibre textures in the β phase of LA106 Mg-Li alloy changed from γ and η to α and ε, which mainly resulted in the dislocation slip. More importantly, UNSM treatment exhibited enhanced strength and improved plasticity of LAE361 and LA106 Mg-Li alloys. The corrosion current density of LAE361 Mg-Li alloy reduced approximately 29.3% by UNSM treatment, while it increased the corrosion current density of LA106 Mg-Li alloy by 189.7%. These studies show that the application of UNSM to improve the corrosion resistance of duplex phases of LA106 Mg-Li alloy needs further investigation. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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13 pages, 9420 KiB

Open AccessFeature PaperArticle

Effect of Micro-Structural Dispersity of SiMo Ductile Iron on High Temperature Performance during Static Oxidation

by Simon N. Lekakh, Asebi Bofah, Larry A. Godlewski and Mei Li

Metals 2022, 12(4), 661; https://doi.org/10.3390/met12040661 - 13 Apr 2022

Cited by 9 | Viewed by 2539

Abstract

High silicon and molybdenum (SiMo) ductile iron is commonly used for car exhaust systems, and its micro-structural dispersity depends on intrinsic parameters, which include alloy composition and inoculation efficiency, as well as extrinsic factors, such as casting wall thickness and molding [...] Read more.

High silicon and molybdenum (SiMo) ductile iron is commonly used for car exhaust systems, and its micro-structural dispersity depends on intrinsic parameters, which include alloy composition and inoculation efficiency, as well as extrinsic factors, such as casting wall thickness and molding material, which define cooling rate during solidification. Micro-structural dispersity is referred to as the degree of heterogeneity of sizes of structural constituencies within the microstructure. A variation in the micro-structural dispersity could impact the high temperature performance of SiMo ductile iron during static oxidation and transient thermo-mechanical loading conditions. In this study, static high temperature tests were performed on SiMo ductile iron solidified in a casting with varying wall thicknesses from 5 mm to 100 mm. The faster solidified specimens (taken from near chilled casting surfaces) had extremely high micro-structural dispersity as compared to the thicker section samples. After thermal exposure, each of the samples were characterized using 2D sections and 3D µCT images, and the results indicated an order of magnitude difference in graphite phase dispersity. The surface degradation was quantified after static oxidation experiments were implemented at temperature intervals between 650 °C and 800 °C. Non-destructive µCT 3D analysis and SEM/EDS were performed on cross sections and used to quantify the scale topology and structure. Carbon analysis was used to decouple the scale formation and decarburization phenomena that occurred within the samples. These methods enabled the quantification of the oxidation of the SiMo cast iron with different micro-structural dispersity levels after being exposed to high temperature static oxidation. Additionally, the complex material behavior during oxidation-assisted transient thermo-mechanical loading will be presented in a separate article. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 3684 KiB

Open AccessArticle

Comparative Study on the Hardness and Wear Resistance of the Remelted Gradient Layer on Ductile Iron Fabricated by Plasma Transferred Arc

by Botao Xiao, Xuefang Yan, Wenming Jiang, Zitian Fan, Qiwen Huang, Jun Fang and Junhuai Xiang

Metals 2022, 12(4), 644; https://doi.org/10.3390/met12040644 - 10 Apr 2022

Cited by 3 | Viewed by 1762

Abstract

Repairing the worn surfaces of wear-resistant workpieces, such as rollers, is one of the main application fields of surface treatment, but the repairing time is often not considered. In fact, the repairing time is very important, since it affects the repair quality and [...] Read more.

Repairing the worn surfaces of wear-resistant workpieces, such as rollers, is one of the main application fields of surface treatment, but the repairing time is often not considered. In fact, the repairing time is very important, since it affects the repair quality and service life of wear-resistant workpieces. In this paper, a remelted gradient coating was prepared on a ductile iron plate by plasma transferred arc to simulate the repair treatment of wear-resistant workpieces. First, two positions in the remelted gradient coating were defined, i.e., the top of the gradient remelted layer was defined as M1, and the position where the hardness was two-thirds of the top of the remelting layer was defined as M2. Next, the time taken to repair the workpiece when the working surface reached M2 was proposed. Finally this method was verified by a comparative study on the microhardness and wear resistance of the M1 and M2. In this paper, the M2 was located at a ~0.5 mm from the top of the remelted gradient layer. The results show that the microhardness of the position of the M1 was higher than that of the position of the M2. However, the wear resistance of the M1 was worse, as confirmed by the wear rates. At the same time, cracks and fragments were observed on the worn surface of the M1 and M2 positions. Furthermore, the coefficient of friction (COF) of the position of M1 was noted to be first higher and subsequently lower than that of the position of M2, owing to the grinding ball entering the substrate. The abrasion mechanisms of both regions were observed to be complex, including oxidative wear, adhesive wear, delamination wear, and/or fretting wear. The experimental data indicate that it is feasible to determine the repair time according to the microhardness of workpieces. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 4768 KiB

Open AccessArticle

Fluorine Effect for Improving Oxidation Resistance of Ti-45Al-8.5Nb Alloy at 1000 °C

by Wanyuan Gui, Yongfeng Liang, Jingyan Qin, Yongsheng Wang and Junpin Lin

Materials 2022, 15(8), 2767; https://doi.org/10.3390/ma15082767 - 9 Apr 2022

Cited by 4 | Viewed by 2014

Abstract

In-depth analyses of the anti-oxidation behavior and structure of γ-TiAl alloys are of great significant for their maintenance and repair in engineering applications. In this work, fluorine-treated Ti-45Al-8.5Nb alloys and fluorine-treated oxidized specimens with artificial defects were prepared by isothermal oxidation treatment at [...] Read more.

In-depth analyses of the anti-oxidation behavior and structure of γ-TiAl alloys are of great significant for their maintenance and repair in engineering applications. In this work, fluorine-treated Ti-45Al-8.5Nb alloys and fluorine-treated oxidized specimens with artificial defects were prepared by isothermal oxidation treatment at 1000 °C. Several characterization methods, including SEM, EDS, XRD and TEM, were used to evaluate the surface microstructure of the fluorine-treated Ti-45Al-8.5Nb alloys and fluorine-treated oxidized specimens with artificial defects. The results indicate that the fluorine promoted the formation of an outer protective film of Al₂O₃, which significantly improved the oxidation resistance. The microcracks of oxidized specimens with the artificial defects provided a rapid diffusion passage for Ti and O elements during the 1000 °C/2 h isothermal oxidation treatment process, resulting in the quick growth of TiO₂ toward the outside. The fine Al₂O₃ constituted a continuous film after the 1000 °C/100 h isothermal oxidation treatment. In particular, Al₂O₃ particles grew toward the substrate, which was ascribed to the good oxidation resistance and adhesion. These results may provide an approach for the repair of protective oxide film on the surface of blades and turbine disks based on γ-TiAl alloys. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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16 pages, 3211 KiB

Open AccessReview

2D Personality of Multifunctional Carbon Nitrides towards Enhanced Catalytic Performance in Energy Storage and Remediation

by Gajendra Kumar Inwati, Virendra Kumar Yadav, Ismat H. Ali, Sai Bhargava Vuggili, Shakti Devi Kakodiya, Mitesh K. Solanki, Krishna Kumar Yadav, Yongtae Ahn, Shalini Yadav, Saiful Islam and Byong-Hun Jeon

Appl. Sci. 2022, 12(8), 3753; https://doi.org/10.3390/app12083753 - 8 Apr 2022

Cited by 6 | Viewed by 2413

Abstract

Numerous scholars in the scientific and management areas have been overly focused on contemporary breakthroughs in two-dimensional objects for multiple prospective applications. Photochemical and electrocatalytic functions of integrated circuits associated with multi-component tools have been enhanced by designing the macro- and microstructures of [...] Read more.

Numerous scholars in the scientific and management areas have been overly focused on contemporary breakthroughs in two-dimensional objects for multiple prospective applications. Photochemical and electrocatalytic functions of integrated circuits associated with multi-component tools have been enhanced by designing the macro- and microstructures of the building blocks. Therefore, the current research attempts to explore a larger spectrum of layered graphitic carbon nitrides (g-C₃N₄) and their derivatives as an efficient catalyst. By executing systematic manufacturing, optimization, and evaluation of its relevance towards astonishing energy storage devices, adsorption chemistry, and remediation, many researchers have focused on the coupling of such 2D carbon nitrides combined with suitable elementals. Hybrid carbon nitrides have been promoted as reliable 2D combinations for the enhanced electrophotocatalytic functionalities, proved by experimental observations and research outputs. By appreciating the modified structural, surface, and physicochemical characteristics of the carbon nitrides, we aim to report a systematic overview of the g-C₃N₄ materials for the application of energy storages and environments. It has altered energy band gap, thermal stability, remarkable dimensional texturing, and electrochemistry, and therefore detailed studies are highlighted by discussing the chemical architectures and atomic alternation of g-C₃N₄ (2D) structures. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 9215 KiB

Open AccessArticle

Insights into the Correlation between Residual Stresses, Phase Transformation, and Wettability of Femtosecond Laser-Irradiated Ductile Iron

by Dhiraj Kumar, Gerhard Liedl, Andreas Otto and Werner Artner

Nanomaterials 2022, 12(8), 1271; https://doi.org/10.3390/nano12081271 - 8 Apr 2022

Viewed by 2104

Abstract

Despite numerous studies on the wettability behavior of ductile iron after ultrafast laser structuring, the correlation between the phase change due to the interaction with an intense pulse and wettability is not yet well understood. In the present work, phase transformations of ductile [...] Read more.

Despite numerous studies on the wettability behavior of ductile iron after ultrafast laser structuring, the correlation between the phase change due to the interaction with an intense pulse and wettability is not yet well understood. In the present work, phase transformations of ductile iron substrates after femtosecond laser irradiation are investigated and correlated with the wettability behavior. Laser parameters such as fluence (F), cumulative fluence (CH), number of pulses (N), and scan speed were varied to produce hierarchical structures with different morphologies and phase concentrations. Our outcomes indicated that substrates with higher concentrations of austenite in the absence of hierarchical structures have a superhydrophilic nature despite being stored in an ambient atmosphere for several days and the application of a vacuum process. In addition, we measured the concomitant residual stresses after laser irradiation using the X-ray diffraction (XRD) method and established a relationship with the doses of CH and induced micro/nanostructures. Transmission electron microscopy (TEM) revealed that laser-structured surfaces are covered with oxides; moreover, phase transformation occurs at the near-subsurface layer. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 4247 KiB

Open AccessFeature PaperArticle

Effects of Carrier, Leveller, and Booster Concentrations on Zinc Plating from Alkaline Zincate Baths

by Abdul Jalil Mohammed and Michael Moats

Metals 2022, 12(4), 621; https://doi.org/10.3390/met12040621 - 3 Apr 2022

Cited by 3 | Viewed by 3473

Abstract

Organic additives are required for alkaline zincate plating baths to obtain an acceptable coating on steel for corrosion protection. The effects and possible interactions of three commercial additives (Eldiem Carrier, Eldiem Booster, and Bright Enhancer 2× on zinc electrodeposition from a high-concentration alkaline [...] Read more.

Organic additives are required for alkaline zincate plating baths to obtain an acceptable coating on steel for corrosion protection. The effects and possible interactions of three commercial additives (Eldiem Carrier, Eldiem Booster, and Bright Enhancer 2× on zinc electrodeposition from a high-concentration alkaline zincate bath were investigated. Visually acceptable deposits were produced within the current density range of 130 to 430 A m⁻² for most additive conditions examined. Over concentration ranges examined, decreasing the booster concentration led to brighter zinc deposits, and an interaction between the carrier and the booster was detected. The additives fostered the formation of compact and adherent coatings as illustrated by scanning electron microscopy. Throwing power and current efficiency were not impacted by the additives over the concentration ranges examined. Linear sweep voltammetry proved that the additives increased the overpotential for zinc deposition. The additive combination that produced the brightest deposit also demonstrated the strongest adsorption of additives in linear sweep voltammetry. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 27330 KiB

Open AccessArticle

Electrochemical Deposition of Hydroxyapatite on Stainless Steel Coated with Tantalum/Tantalum Nitride Using Simulated Body Fluid as an Electrolytic Medium

by Rafael Uribe, Andrea Uvillús, Lenys Fernández, Omar Bonilla, Angélica Jara and Gema González

Coatings 2022, 12(4), 440; https://doi.org/10.3390/coatings12040440 - 24 Mar 2022

Cited by 9 | Viewed by 3455

Abstract

In the present work the electrochemical deposition of hydroxyapatite using simulated body fluid (SBF) as an electrolytic medium was carried out on Ta and Ta/TaN coatings on BIOLINE stainless steel SS316LVM (SS). The electrochemical deposition performed on each substrate for 3000 and 6000 [...] Read more.

In the present work the electrochemical deposition of hydroxyapatite using simulated body fluid (SBF) as an electrolytic medium was carried out on Ta and Ta/TaN coatings on BIOLINE stainless steel SS316LVM (SS). The electrochemical deposition performed on each substrate for 3000 and 6000 s, at different potentials were determined from cyclic voltammetry. The best conditions found were −1.4 V for bare SS and −1.7 V for Ta/TaN coating. The structural characterization was carried out by SEM, FTIR, XRD, and contact angle measurements. The electrochemical characterization was done by electrochemical impedance (EIS), which allowed us to know the capacitive and resistive character of the substrates. The substrate (Ta/TaN)/SS at −1.7 V 6000 s presented the largest formation of a nonstoichiometric hydroxyapatite with a uniform distribution on the substrate, implying that Ta–OH is formed on the tantalum metallic surface, due to formation of the passivation layer of tantalum oxide. These groups attract Ca²⁺ ions and PO₄³⁻ ions absorbed on the surface will form the precursors of the apatite crystals that finally transform to hydroxyapatite. The electrodeposition of HAp the double layer Ta/TaN resulted in a more uniform and denser layer than SS alone. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 61088 KiB

Open AccessArticle

Experimental Study on the Quenching Behavior of a Copper Cube in the Cellulose Nanofiber Solution

by Hundong Choi, Subin Jeong and Kwon-Yeong Lee

Nanomaterials 2022, 12(6), 1033; https://doi.org/10.3390/nano12061033 - 21 Mar 2022

Viewed by 2271

Abstract

This study investigates the quenching behavior and heat transfer characteristics of a copper cube immersed in cellulose nanofiber (CNF) solutions. The heat transfer performance of CNF solutions during boiling has been examined in several studies, but the quenching behavior of CNF solutions, which [...] Read more.

This study investigates the quenching behavior and heat transfer characteristics of a copper cube immersed in cellulose nanofiber (CNF) solutions. The heat transfer performance of CNF solutions during boiling has been examined in several studies, but the quenching behavior of CNF solutions, which is an important heat transfer method, has not been evaluated. In this study, four copper cubes with the same dimensions and four different quenchants (deionized water and 0.01%, 0.1% and 0.5% CNF solutions) were prepared. A copper cube heated to greater than 600 °C was submerged three times in the quenchant. This was repeated with different copper cubes in each of the quenchants. The time at which the heated copper cube convectively transferred heat to the surroundings was recorded. The cooling time was shortest when the cube was immersed in a 0.5% CNF solution for the first time. The average cooling time for quenching in the 0.5% CNF solution was 30.3% shorter than that in DI water. In this study, film boiling during quenching was thoroughly observed and analyzed to explain the cause of enhancement in heat transfer efficiency. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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10 pages, 2677 KiB

Open AccessArticle

Evolution of Nanostructured Carbon Coatings Quality via RT-CVD and Their Tribological Behavior on Nodular Cast Iron

by Alejandra Moreno-Bárcenas, Jesus Alejandro Arizpe Zapata, Miguel Ángel Esneider Alcalá, Jaime Téllez Ramírez, Antonio Magaña Hernández and Alejandra García-García

Metals 2022, 12(3), 517; https://doi.org/10.3390/met12030517 - 18 Mar 2022

Cited by 1 | Viewed by 2521

Abstract

One of the most critical problems in industry is the wear of materials. Graphene, as a tribological coating, has shown a tremendous impact on sliding surfaces. In this work, a few layers of graphene were grown on a nodular cast iron substrate, a [...] Read more.

One of the most critical problems in industry is the wear of materials. Graphene, as a tribological coating, has shown a tremendous impact on sliding surfaces. In this work, a few layers of graphene were grown on a nodular cast iron substrate, a material used in camshafts. The studied synthesis parameters in a rapid thermal chemical vapor deposition (CVD) furnace and the quality of the final coating are presented. The influence of hydrogen flow and cooling rate was evaluated, obtaining the best results in the few layers of graphene structure and deposition at 10 sccm and 4 °C/min. A standard ball-on-disk tribometer was used to assess the coefficient of friction on a few layers of graphene on nodular cast iron substrates. Laboratory test results show that the few layers of graphene coating resulted in a 60% reduction in coefficient of friction and close to a 70% reduction in volume removed versus the uncoated substrates. The surface of the substrate was not modified before a few layers of graphene growth to have a working surface close to camshafts obtained by the industrial process at ARBOMEX SA de CV. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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11 pages, 1405 KiB

Open AccessArticle

Biobased Approach for Synthesis of Polymers and Sustainable Formulation of Industrial Hardeners

by Lorenzo Veronico, Michele Andriani, Michele Casiello, Pietro Cotugno, Caterina Fusco, Luigi Gentile, Antonio Monopoli and Lucia D’Accolti

Coatings 2022, 12(3), 361; https://doi.org/10.3390/coatings12030361 - 8 Mar 2022

Cited by 2 | Viewed by 2719

Abstract

The adhesive manufacturing industry needs more eco-sustainable processes. In this regard, the main road is to replace raw fossil materials with renewable resources or waste biomass, and simultaneously improve synthetic steps by using clean and greener reagents under mild conditions. In this paper, [...] Read more.

The adhesive manufacturing industry needs more eco-sustainable processes. In this regard, the main road is to replace raw fossil materials with renewable resources or waste biomass, and simultaneously improve synthetic steps by using clean and greener reagents under mild conditions. In this paper, a synthetic pathway for producing biobased succinyl peroxide (SP) from waste biomass is reported, and then the application range of this polymerization agent to methacrylates and styrene-free resins is extended. At the same time, new formulations of pastes based on benzoyl or succinyl peroxide, displaying an almost complete biobased carbon content, are investigated and tested as cross-linking agents for mastic marble and unsaturated polyester resins. Physicochemical characterization of the final products and polymers is carried out with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance (NMR) and peak exothermic curve analyses. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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18 pages, 8449 KiB

Open AccessArticle

High-Speed Erosion Behavior of Hydrophobic Micro/Nanostructured Titanium Surfaces

by Yong Chen and Jiguo Zhang

Nanomaterials 2022, 12(5), 880; https://doi.org/10.3390/nano12050880 - 7 Mar 2022

Cited by 7 | Viewed by 2523

Abstract

Ice accretion on aircrafts or their engines can cause serious problems and even accidents. Traditional anti-icing and de-icing systems reduce engine efficiency, which can be improved by the use of hydrophobic/icephobic coatings or surfaces that reduce the amount of bleed air or electric [...] Read more.

Ice accretion on aircrafts or their engines can cause serious problems and even accidents. Traditional anti-icing and de-icing systems reduce engine efficiency, which can be improved by the use of hydrophobic/icephobic coatings or surfaces that reduce the amount of bleed air or electric power needed. These hydrophobic/icephobic coatings or surfaces are eroded by high-speed air flow, water droplets, ice crystals, sand, and volcanic ash, resulting in the degradation, material loss, or deterioration of the coating’s waterproof and anti-icing properties. Thus, the durability of hydrophobic micro/nanostructured surfaces is a major concern in aircraft applications. However, the mechanism responsible for material loss in hydrophobic micro/nanostructured surfaces resulting from high-speed erosion remains unclear. In this paper, hydrophobic titanium alloy surfaces with cubic pit arrays are fabricated by photoetching and tested using a high-speed sand erosion rig. Under the same impact conditions, the erosion rates of the micro/nanostructured titanium surfaces were similar to those of smooth titanium alloy, implying that the hydrophobic surface fabricated on the bulk material had erosion-resistant capabilities. The material loss mechanisms of the micro/nanostructures under different impact angles were compared, providing useful information for the future optimization of micro/nanostructures with the goal of improved erosion resistance. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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