Coatings

17 pages, 19026 KiB

Open AccessArticle

Preparation of SrAl₂O₄: Eu²⁺, Dy³⁺ Powder by Combustion Method and Application in Anticounterfeiting

by Peng Gao, Jigang Wang, Jiao Wu, Qingqing Xu, Lixue Yang, Quanxiao Liu, Yuansheng Qi and Zhenjun Li

Coatings 2023, 13(4), 808; https://doi.org/10.3390/coatings13040808 - 21 Apr 2023

Cited by 7 | Viewed by 3406

Abstract

Green emitting long afterglow phosphor SrAl₂O₄: Eu²⁺, Dy³⁺ was synthesized via the combustion method. The physical phase analysis was carried out by X-ray diffraction, the results show that the introduction of Eu²⁺ into the lattice [...] Read more.

Green emitting long afterglow phosphor SrAl₂O₄: Eu²⁺, Dy³⁺ was synthesized via the combustion method. The physical phase analysis was carried out by X-ray diffraction, the results show that the introduction of Eu²⁺ into the lattice of the matrix resulted in a broad green emission centered at 508 nm, which is ascribed to the characteristic 4f⁶5d¹ to 4f⁷ electronic dipole allowed transition of Eu²⁺ ions. The doping of Eu²⁺ and Dy³⁺ did not change the physical phase of the crystals. Dy³⁺, as a coactivator, does not emit light itself, but can generate holes to form a trap energy level, which acts as an electron trap center to capture some of the electrons generated by the excitation of Eu²⁺. After excitation has ceased, let them gradually to transfer to the ground state for long afterglow luminescence. Then, we investigate the optical characterizations of different samples excited by X-ray. We found that SrAl₂O₄: Eu²⁺, 0.5% Dy³⁺ has this higher luminous intensity and afterglow. Its fluorescence lifetime is about 720 ns, and its quantum yield can reach 15.18%. Through search engine marketing (SEM) and energy dispersive X-ray spectroscopy (EDX), it has been proved that the sample has been successfully synthesized and its component content has been confirmed. The Eg value calculated from the diffuse reflectance spectrum is 4.61eV. The prepared SrAl₂O₄: Eu²⁺, Dy³⁺ luminescent powder is combined with Polydimethylsiloxane substrate for anticounterfeiting application, which provides a novel idea and method for the development of the anticounterfeiting field. Full article

(This article belongs to the Special Issue Optoelectronic Thin Films)

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12 pages, 5797 KiB

Open AccessCommunication

Fabrication of Modified Polyurethane Sponge with Excellent Flame Retardant and the Modification Mechanism

by Hang Li, Chen-Yang Zhang, Ya-Ling Yu, Chang-Jin Liang, Guang-Ming Yuan, Huan Yang, Yun-Ying Wu and Shao-Min Lin

Coatings 2023, 13(4), 807; https://doi.org/10.3390/coatings13040807 - 21 Apr 2023

Cited by 1 | Viewed by 1813

Abstract

Research on polyurethane sponge (PUS), a widely used polymer material, and its flame-retardant performance is of great significance. In this study, PUS was modified to prepare a highly efficient flame-retardant composite using a soaking method. The PUS nearly vanished at 11 s after [...] Read more.

Research on polyurethane sponge (PUS), a widely used polymer material, and its flame-retardant performance is of great significance. In this study, PUS was modified to prepare a highly efficient flame-retardant composite using a soaking method. The PUS nearly vanished at 11 s after ignition, and the solid residue rate of the PUS was 5.65 wt% at 750 °C. The net structure, composed of nano SiO₂, was maintained in the modified PUS at 750 °C, and the solid residue rate was 69.23%. The maximum HRR of the PUS decreased from 617 W/g to 40 W/g and the THR of the sample reduced from 33 kJ/g to 9 kJ/g after modification. The results suggested that the modified PUS gained excellent flame-retardant performance. The flame-retardant layer in the modified PUS was amorphous. The surface of the modified PUS was rich in Si, O, and C elements and lacked a N element, suggesting that inorganic flame retardants were abundant on the surface layer of the modified PUS. The Si-O-C vibration and Si-O-Si stretching in the modified PUS indicates that the organic–inorganic hybrid structure formed on the PUS surface, which could be attributed to the polymerization and condensation of the silica precursor. Thus, the modified PUS provided an excellent flame-retardant layer. The results are of interest for producing efficient flame-retardant PUS using a simple method. Full article

(This article belongs to the Special Issue New Developments of Protective Coatings, Organic Polymers, and Surface Analysis)

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16 pages, 4769 KiB

Open AccessArticle

Tribological Properties and Corrosion Resistance of Stellite 20 Alloy Coating Prepared by HVOF and HVAF

by Zhiqiang Zhou, Jiahui Yong, Jiaoshan Hao, Deen Sun, Qian Cheng, Huan Jing and Zhongyun Zhou

Coatings 2023, 13(4), 806; https://doi.org/10.3390/coatings13040806 - 21 Apr 2023

Cited by 3 | Viewed by 2147

Abstract

This study examines the tribological and corrosion properties of Stellite 20 alloy coatings on F310H heat-resistant stainless steel that were prepared using HVOF and HVAF supersonic flame spraying techniques. To investigate the coatings’ microstructure, phase, microhardness, wear, and corrosion resistance, a range of [...] Read more.

This study examines the tribological and corrosion properties of Stellite 20 alloy coatings on F310H heat-resistant stainless steel that were prepared using HVOF and HVAF supersonic flame spraying techniques. To investigate the coatings’ microstructure, phase, microhardness, wear, and corrosion resistance, a range of characterization techniques, including SEM, EDS, XRD, microhardness, and friction wear-testers, weas employed. The results indicate that both HVOF and HVAF-prepared coatings exhibit a dense structure with porosity of 0.41% and 0.32%, respectively. The coatings are composed of γ-Co solid solution, ε-Co solid solution, Cr-rich solid solution, Cr₇C₃, WC, and CoCr₂O₄ phases. The microhardness of the Stellite 20 coatings prepared by HVOF and HVAF methods was 610 HV_0.3 and 690 HV_0.3, respectively, which is three times higher than that of the F310H stainless steel substrate. The wear mechanism of the HVAF coating is abrasive wear, while the wear mechanism of the HVOF coating is mainly fatigue wear with slight abrasive wear. The HVAF coating demonstrates superior wear resistance due to its higher flame velocity, denser coating, and higher average microhardness. In contrast, the HVOF coating shows a higher friction coefficient stability due to its lower hardness dispersion. The corrosion potentials of the HVOF and HVAF coatings are −0.532 V and −0.376 V, respectively, with corresponding corrosion current densities of 1.692 × 10⁻⁷ A·cm⁻² and 6.268 × 10⁻⁷ A·cm⁻², respectively. Compared to the HVOF coating, the Stellite 20 coating prepared using HVAF technology exhibits better wear and corrosion resistance. Full article

(This article belongs to the Special Issue Advanced Corrosion and High Temperature Protection through Surface Modification and Coatings)

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12 pages, 2749 KiB

Open AccessArticle

Improvement of Piezoelectricity of (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃ Ceramics Modified by a Combination of Porosity and Sm³⁺ Doping

by Siyu Xia, Huiling Du, Zhuo Li, Fan Zhao, Qianqian Li, Yuxuan Hu and Le Kang

Coatings 2023, 13(4), 805; https://doi.org/10.3390/coatings13040805 - 21 Apr 2023

Cited by 5 | Viewed by 1944

Abstract

Porous lead-free piezoelectric ceramics are characterized by their environment-friendly, light weight, and large specific surface area. The optimization of porous Na_0.5Bi_0.5TiO₃-based lead-free piezoelectric ceramics can improve piezoelectric properties, enhance force–electric coupling characteristics, and effectively promote energy conversion, [...] Read more.

Porous lead-free piezoelectric ceramics are characterized by their environment-friendly, light weight, and large specific surface area. The optimization of porous Na_0.5Bi_0.5TiO₃-based lead-free piezoelectric ceramics can improve piezoelectric properties, enhance force–electric coupling characteristics, and effectively promote energy conversion, expanding the application in force-electric coupling devices. This study aimed to prepare [Sm_x(Bi_0.5Na_0.5)_1−3x/2]_0.94Ba_0.06TiO₃ (x = 0, 0.01, 0.02, 0.03, 0.04) lead-free ceramics with porous structures, resulting in the piezoelectric constant d₃₃ = 131 pC/N and the plane electromechanical coupling coefficient k_p = 0.213 at x = 0.01. The presence of pores in lead-free ceramics has a direct impact on the domain structure and can cause the depolarization process to relax. Then, the soft doping of Sm³⁺ makes the A-site ion in porous (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃ ceramics occupancy inhomogeneous and generates cation vacancies, which induces lattice distortion and makes the domain wall motion easier, resulting in the improvement of piezoelectric properties and electromechanical coupling parameters. Furthermore, the piezoelectric oscillator exhibits greater resistance to resonant coupling in the radial extension vibration mode. These results infer that a combination of porosity and Sm³⁺ doping renders (Bi_0.5Na_0.5)_0.94Ba_0.06TiO₃ ceramics base material for piezoelectric resonators, providing a scientific basis for their application in force–electric coupling devices, such as piezoelectric resonant gas sensors. Full article

(This article belongs to the Special Issue High-Performance Dielectric Ceramic for Energy Storage Capacitors)

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12 pages, 4893 KiB

Open AccessCommunication

Effect of Various Metal Oxide Insulating Layers on the Magnetic Properties of Fe-Si-Cr Systems

by Zhenyi Huang, Huaqin Huang, Hao He, Zhaoyang Wu, Xuesong Wang and Rui Wang

Coatings 2023, 13(4), 804; https://doi.org/10.3390/coatings13040804 - 20 Apr 2023

Cited by 3 | Viewed by 2059

Abstract

Iron-based soft magnetic composites (SMCs) are the key components of high-frequency electromagnetic systems. Selecting a suitable insulating oxide layer and ensuring the integrity and homogeneity of the heterogeneous core–shell structure of SMCs are essential for optimizing their magnetic properties. In this study, four [...] Read more.

Iron-based soft magnetic composites (SMCs) are the key components of high-frequency electromagnetic systems. Selecting a suitable insulating oxide layer and ensuring the integrity and homogeneity of the heterogeneous core–shell structure of SMCs are essential for optimizing their magnetic properties. In this study, four types of SMCs—Fe-Si-Cr/ZrO₂, Fe-Si-Cr/TiO₂, Fe-Si-Cr/MgO, and Fe-Si-Cr/CaO—were prepared via ball milling, followed by hot-press sintering. The differences between the microscopic morphologies and magnetic fproperties of the Fe-Si-Cr/AO_x SMCs prepared using four different metal oxides were investigated. ZrO₂, TiO₂, MgO, and CaO were successfully coated on the surface of the Fe-Si-Cr alloy powders through ball milling, forming a heterogeneous Fe-Si-Cr/AO_x core–shell structure with the Fe-Si-Cr alloy powder as the core and the metal oxide as the shell. ZrO₂ is relatively hard and less prone to breakage and refinement during ball milling, resulting in a lower degree of agglomeration on the surface of the composites and prevention of peeling and collapse during hot-press sintering. When ZrO₂ was used as the insulation layer, the magnetic dilution effect was minimized, resulting in the highest resistivity (4.2 mΩ·cm), lowest total loss (580.8 kW/m³ for P_10mt/100kHz), and lowest eddy current loss (470.0 kW/m³ for P_{ec 10mt/100kHz}), while the permeability stabilized earlier at lower frequencies. Full article

(This article belongs to the Section Ceramic Coatings and Engineering Technology)

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13 pages, 10601 KiB

Open AccessArticle

Formation of Bioresorbable Fe-Cu-Hydroxyapatite Composite by 3D Printing

by Valentina Vadimovna Chebodaeva, Nikita Andreevich Luginin, Anastasiya Evgenievna Rezvanova, Natalya Valentinovna Svarovskaya, Konstantin Vladimirovich Suliz, Ludmila Yurevna Ivanova, Margarita Andreevna Khimich, Nikita Evgenievich Toropkov, Ivan Aleksandrovich Glukhov, Andrey Aleksandrovich Miller, Sergey Olegovich Kazantsev and Maksim Germanovich Krinitcyn

Coatings 2023, 13(4), 803; https://doi.org/10.3390/coatings13040803 - 20 Apr 2023

Cited by 2 | Viewed by 1675

Abstract

Studies of the microstructure, phase composition and mechanical characteristics, namely the microhardness of metal–ceramic composites made of Fe 90 wt.%–Cu 10 wt.% powder and hydroxyapatite (Fe-Cu-HA), are presented in the manuscript. The composite material was obtained using additive manufacturing based on the 3D-printing [...] Read more.

Studies of the microstructure, phase composition and mechanical characteristics, namely the microhardness of metal–ceramic composites made of Fe 90 wt.%–Cu 10 wt.% powder and hydroxyapatite (Fe-Cu-HA), are presented in the manuscript. The composite material was obtained using additive manufacturing based on the 3D-printing method, with different content levels of powder (40, 45 and 50%) and polymer parts (60, 55 and 50%). It is shown that varying the proportion of Fe-Cu-HA powder does not significantly affect the elemental and phase compositions of the material. The X-ray phase analysis showed the presence of three phases in the material: alpha iron, copper and hydroxyapatite. It is shown in the experiment that an increase in the polymer component of the composite leads to an increase in the defectiveness of the structure, as well as an increase in microstresses. An increase in the mechanical properties of the composite (Vickers microhardness), along with a decrease in the percentage of Fe-Cu-HA powder from 50 to 40%, was established. At the same time, the composite containing 45% Fe-Cu-HA powder demonstrated the maximum increase in the microhardness of the composite by ~26% compared to the composite containing 50% Fe-Cu-HA powder, which is due to the more uniform distribution of components. Full article

(This article belongs to the Special Issue Surface Modification Technology of Biomedical Metals)

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14 pages, 56059 KiB

Open AccessArticle

Preliminary Study on Electrodeposition of Copper Platings and Codeposition of Carbon Nanotubes from Organic Solvent

by Jae-Hyeok Park, Yusei Fujita, Takeshi Hagio, Vanpaseuth Phouthavong, Yuki Kamimoto, Takeshi Bessho and Ryoichi Ichino

Coatings 2023, 13(4), 802; https://doi.org/10.3390/coatings13040802 - 20 Apr 2023

Cited by 1 | Viewed by 2492

Abstract

Metal/carbon composite plating is an effective strategy for improving and adding properties to metal plating by incorporating carbon materials into the metal matrices. Copper (Cu) is widely applied, particularly in the areas of heat management and electronic packaging owing to its high thermal [...] Read more.

Metal/carbon composite plating is an effective strategy for improving and adding properties to metal plating by incorporating carbon materials into the metal matrices. Copper (Cu) is widely applied, particularly in the areas of heat management and electronic packaging owing to its high thermal and electrical conductivities, which can be further improved together with improvements in mechanical properties by compositing it with carbon nanotubes (CNTs). However, because hydrophobic CNTs are hardly dispersible in aqueous solutions, additional intense acid treatment or the addition of dispersants is required for their dispersion. Moreover, previous studies have reported that these methods suffer from deterioration of composite material performance through the destruction of the CNT surface or the inclusion of dispersants into the plating. Therefore, in this study, the electrodeposition of a Cu/CNT composite in a non-aqueous solvent that can disperse CNTs without any additional treatment is investigated. The experimental results show that it is possible to deposit Cu from a N-methyl-2-pyrrolidone containing copper iodide and potassium iodide. Furthermore, Cu/CNT composite platings containing CNTs up to 0.12 mass% were prepared by constant current electrolysis, and applying pulse electrolysis can increase the CNTs content up to 0.22 mass%. Full article

(This article belongs to the Special Issue Material Surface Treatment Technology for a New Era)

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10 pages, 4590 KiB

Open AccessCommunication

Electrodeposition of Soft Magnetic Fe-W-P Alloy Coatings from an Acidic Electrolyte

by Natalia Kovalska, Antonio Mulone, Jordi Sort, Uta Klement, Gurdial Blugan, Wolfgang Hansal and Wolfgang Kautek

Coatings 2023, 13(4), 801; https://doi.org/10.3390/coatings13040801 - 20 Apr 2023

Viewed by 1455

Abstract

Fe-W-P coatings were deposited from a newly developed electrolytic bath. The effect of plating parameters, such as electrolyte current density and pH has been studied. It was found that the pH has a very strong effect on the phosphorous content of the coatings. [...] Read more.

Fe-W-P coatings were deposited from a newly developed electrolytic bath. The effect of plating parameters, such as electrolyte current density and pH has been studied. It was found that the pH has a very strong effect on the phosphorous content of the coatings. Metallic-like, non-powdery alloys of Fe-W-P deposits with no cracks (lowly stressed) can be obtained at a lower pH (<3), exhibiting high phosphorus (up to 13 at.%) and low tungsten (6 at.%) contents. At a higher pH (>3), the composition changes to low phosphorus and high tungsten content, showing a matte, greyish, and rough surface. The applied current density also influences the morphology and the amount of phosphorous content. The deposits showed an amorphous structure for all samples with soft ferromagnetic properties. Full article

(This article belongs to the Special Issue Electrochemical Deposition: Properties and Applications)

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16 pages, 6908 KiB

Open AccessFeature PaperArticle

Effect of the Surface Film Formed by Hydrogen Charging on the Corrosion Behavior of an As-Cast Mg–8%Li (in wt. %) Alloy

by Shuo Wang, Daokui Xu, Baojie Wang, Dongliang Wang, Zhiqiang Zhang and Xiangbo Xu

Coatings 2023, 13(4), 800; https://doi.org/10.3390/coatings13040800 - 20 Apr 2023

Cited by 2 | Viewed by 1869

Abstract

In this study, the effect of electrochemical hydrogen charging on the corrosion behavior of an as-cast Mg–8%Li alloy was investigated. It was revealed that after being cathodically hydrogen charged in a 0.1 M NaCl solution at a constant current density of 50 mA/cm [...] Read more.

In this study, the effect of electrochemical hydrogen charging on the corrosion behavior of an as-cast Mg–8%Li alloy was investigated. It was revealed that after being cathodically hydrogen charged in a 0.1 M NaCl solution at a constant current density of 50 mA/cm² for 3 h, a product film with an average thickness of 20 μm was formed in the α-Mg phase, whilst the average thickness of the product film being formed in the β-Li phase was 6 μm. When the charging time was prolonged to 18 h, the thicknesses of the product films being formed on the α-Mg and β-Li phases were increased to 75 and 20 μm, respectively. The results of the grazing incidence X-ray diffraction (GIXRD) testing showed that the product films of the differently charged samples mainly consisted of Mg(OH)₂, LiOH and Li₂CO₃. The formed product films on the two matrix phases were dense and could hinder the erosion of Cl⁻ in a solution, and hence improved the corrosion resistance of the alloy. After being hydrogen charged for 3 h, the charge-transfer resistance (R_ct) value of the alloy was increased from 527 to 1219 Ω·cm². However, when the hydrogen charging time was prolonged to 18 h, the R_ct was slightly reduced to 1039 Ω·cm² due to the cracking of the surface product films and the interfacial cracking of the film/substrate matrix. Full article

(This article belongs to the Topic Environmental Sensitivity and Safety Assessment of Materials)

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15 pages, 6878 KiB

Open AccessArticle

Evaluation of Fracture Toughness of Plasma Electrolytic Oxidized Al₂O₃-ZrO₂ Coatings Utilizing Nano-Scratch Technique

by Mehri Hashemzadeh, Frank Simchen, Lisa Winter and Thomas Lampke

Coatings 2023, 13(4), 799; https://doi.org/10.3390/coatings13040799 - 20 Apr 2023

Cited by 4 | Viewed by 2874

Abstract

Al₂O₃ coatings, which can be produced by plasma electrolytic oxidation (PEO) on aluminum substrates, provide an excellent protection against corrosion and wear. However, due to the brittle nature of the oxide ceramic, the fracture toughness is limited. One approach to [...] Read more.

Al₂O₃ coatings, which can be produced by plasma electrolytic oxidation (PEO) on aluminum substrates, provide an excellent protection against corrosion and wear. However, due to the brittle nature of the oxide ceramic, the fracture toughness is limited. One approach to enhance the tolerance to fracture is the incorporation of ZrO₂ to form zirconia toughened alumina (ZTA). In addition to its use as a bulk material, the application as a coating material enables a broader field of application. In this study, an Al₂O₃-ZrO₂ composite coating was applied on a 6082 aluminum alloy using an aluminate-phosphate-based electrolytic solution containing a Zr-based salt. Polarization measurement as an indicator of the passivability of a given system revealed that Zr-based salt improves the passivation of the aluminum alloy. The coatings’ characteristics were evaluated by SEM, EDS, and XRD. ZrO₂ incorporated into alumina as a metastable high-temperature modification led to a thicker coating with new morphologies including lamellar and dendritic structures. Nano-indentation showed that the incorporated Zr increase the average hardness of the compact layer from 16 GPa to 18 GPa. The fracture toughness of the coatings was investigated locally with nano-scratches applied on the compact outer layer of the coatings’ cross-sections. The Zr-containing electrolytic solution resulted in a coating with significantly higher fracture toughness (6.9 MPa∙m^1/2) in comparison with the Zr-free electrolytic solution (4.6 MPa∙m^1/2). Therefore, it is shown, that the PEO process stabilized a high-temperature allotrope of zirconia at room temperature without the need for rare-earth dopants such as Y₂O₃. Furthermore, it was demonstrated that the nano-scratch method is a suitable and accurate technique for the investigation of the fracture toughness of coatings with inherent cracks. Full article

(This article belongs to the Special Issue Functional Coatings for Metallic and Ceramic Materials)

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8 pages, 1218 KiB

Open AccessCommunication

Modeling of Ionizing Radiation Effects for Negative Capacitance Field-Effect Transistors

by Yongguang Xiao, Xianghua Da, Haize Cao, Ke Xiong, Gang Li and Minghua Tang

Coatings 2023, 13(4), 798; https://doi.org/10.3390/coatings13040798 - 20 Apr 2023

Cited by 1 | Viewed by 1362

Abstract

A theoretical model for simulating ionizing radiation effects on negative capacitance field-effect transistors (NCFETs) with a metal–ferroelectric–insulator–semiconductor (MFIS) structure was established. Based on the model, the effects of total ionizing dose (TID) and dose rate on the surface potential, ferroelectric capacitance, voltage amplification [...] Read more.

A theoretical model for simulating ionizing radiation effects on negative capacitance field-effect transistors (NCFETs) with a metal–ferroelectric–insulator–semiconductor (MFIS) structure was established. Based on the model, the effects of total ionizing dose (TID) and dose rate on the surface potential, ferroelectric capacitance, voltage amplification factor, and transfer characteristics of NCFETs were investigated. The simulation results demonstrated that, with the increase in total dose, the curves of surface potential versus gate voltage and driving current versus gate voltage shift left significantly, resulting in the point of voltage amplification shifting left. Meanwhile, with the increase in dose rate, the amplitude of both the surface potential and driving current decreases slightly. Meanwhile, the derived result indicated that relatively thin ferroelectric thickness can effectively reduce the effect of TID. It is expected that this model can be helpful for analyzing the radiation effects of NCFETs. Full article

(This article belongs to the Special Issue Advanced Ferroelectric Materials and Films: Properties and Applications for Post Moorish Era)

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13 pages, 2879 KiB

Open AccessArticle

A Study of the Laser-Assisted Alloying Effect on Plasmonic Properties of Au-Pd Nanostructured Film Using Surface-Enhanced Raman Spectroscopy

by Chawki Awada and Francesco Ruffino

Coatings 2023, 13(4), 797; https://doi.org/10.3390/coatings13040797 - 19 Apr 2023

Cited by 1 | Viewed by 1579

Abstract

In this work, we report a study on the effect of the laser-assisted alloying effect on plasmonic properties of Pd and Au-Pd nanostructures using surface-enhanced Raman spectroscopy (SERS). The monometallic and bimetallic nanostructures are formed by nanosecond-laser induced de-wetting and the alloying of [...] Read more.

In this work, we report a study on the effect of the laser-assisted alloying effect on plasmonic properties of Pd and Au-Pd nanostructures using surface-enhanced Raman spectroscopy (SERS). The monometallic and bimetallic nanostructures are formed by nanosecond-laser induced de-wetting and the alloying of pure Pd and bimetallic Au-Pd nanoscale-thick films deposited on a transparent and conductive substrate. The morphological characteristics of the nanostructures were changed by controlling the laser fluence. Then, 4-nitrithiophenol (4-NTP) was used as an adsorbed molecule on the surface of the nanostructures to analyze the resulting SERS properties. A quantitative analysis was reported using the SERS profile properties, such as FWHM, amplitude, and Raman peak position variation. An excellent correlation between the variation of SERS properties and the nanostructures’ size was confirmed. The optical enhancement factor was estimated for Pd and Au-Pd nanostructures for the laser fluence (0, 0.5, 0.75, 1, and 1.5 J/cm²). Full article

(This article belongs to the Special Issue Fabrication of Plasmonic Thin Films, Their Characterization and Applications)

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20 pages, 3716 KiB

Open AccessReview

Development of Hetero-Junction Silicon Solar Cells with Intrinsic Thin Layer: A Review

by Nikolay Chuchvaga, Kairat Zholdybayev, Kazybek Aimaganbetov, Sultan Zhantuarov and Abay Serikkanov

Coatings 2023, 13(4), 796; https://doi.org/10.3390/coatings13040796 - 19 Apr 2023

Cited by 7 | Viewed by 6042

Abstract

This paper presents the history of the development of heterojunction silicon solar cells from the first studies of the amorphous silicon/crystalline silicon junction to the creation of HJT solar cells with novel structure and contact grid designs. In addition to explanation of the [...] Read more.

This paper presents the history of the development of heterojunction silicon solar cells from the first studies of the amorphous silicon/crystalline silicon junction to the creation of HJT solar cells with novel structure and contact grid designs. In addition to explanation of the current advances in the field of research of this type of solar cells, the purpose of this paper is to show possible ways to improve the structure of the amorphous silicon/crystalline silicon-based solar cells for further improvement of the optical and electrical parameters of the devices by using of numerical simulation method and current hypotheses. This paper briefly describes the history, beginning from the first studies of and research of HJT-structure solar cells. It raises questions about the advantages and existing problems of optimization of HJT solar cells. The authors of this paper are proposing further ways of design development of HJT solar cells. Full article

(This article belongs to the Special Issue Advanced Functional Nanostructured Films and Coatings for Energy Applications)

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16 pages, 4662 KiB

Open AccessArticle

Influence of Active Packaging Covered with Coatings Containing Mixtures of Glycyrrhiza L. and Scutellaria baicalensis Extracts on the Microbial Purity and Texture of Sliced Chicken Sausages

by Magdalena Ordon, Weronika Burdajewicz, Joanna Pitucha, Alicja Tarnowiecka-Kuca and Małgorzata Mizielińska

Coatings 2023, 13(4), 795; https://doi.org/10.3390/coatings13040795 - 19 Apr 2023

Cited by 2 | Viewed by 2631

Abstract

Sliced chicken sausages were packed into polyethylene (PE) bags (control samples) and PE bags were covered with active coatings. The sausage slices were separated into two categories: non-coated (control samples) spacers and spacers covered with the antimicrobial coating. The chicken sausage slices were [...] Read more.

Sliced chicken sausages were packed into polyethylene (PE) bags (control samples) and PE bags were covered with active coatings. The sausage slices were separated into two categories: non-coated (control samples) spacers and spacers covered with the antimicrobial coating. The chicken sausage slices were stored at 5 °C and examined after 72 h and 144 h storage times. Results obtained in this work demonstrated that the springiness of the chicken sausage slices decreased after 72 h of storage for all of the analysed packaging bags/films. Different results were obtained after 144 h of storage. In contrast to the samples stored in uncoated bags, the springiness of sausage slices stored in the active packaging decreased. Textural parameters with regards to chewiness, gumminess and cohesiveness were found to be greater after 72 h of storage for samples stored in the uncoated bags than for the sausage stored in active packaging materials. Contradictory results were observed after 144 h of storage. It was found that water loss from the sliced chicken sausage in active bags was lower than in uncoated PE bags. Microbial analysis showed that the packaging material covered with a coating containing a mixture of Scutellaria baicalensis* and Glycyrrhiza L. extracts in the ratio of 1:2 was found to be more effective against mesophilic bacterial cells than a coating containing the mixture of these extracts in the ratio of 2*:1 after 72 h. The effect of active coatings on the number of bacterial cells was negligible after 144 h of storage. Full article

(This article belongs to the Special Issue Coatings and Thin Films for Food Packaging Applications)

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9 pages, 2199 KiB

Open AccessArticle

Molecular Dynamics Simulation of the Incident Energy Effect on the Properties of TiN Films

by Jiao Li, Jun Lin, Qingyuan Ma, Hanxiao Luan, Lihua Zhu, Ruqing Bai, Guiwei Dong, Diangang Wang, Yanjin Guan and Xiaocui Zhang

Coatings 2023, 13(4), 794; https://doi.org/10.3390/coatings13040794 - 19 Apr 2023

Cited by 3 | Viewed by 1793

Abstract

In this work, to investigate the physical vapor deposition (PVD)-deposited TiN coating on the TiN(001) substrate, the process was simulated using the molecular dynamics (MD) method with the 2NN-MEAM (nearest-neighbor modified embedded atom method) potential. The results revealed that the growth mode of [...] Read more.

In this work, to investigate the physical vapor deposition (PVD)-deposited TiN coating on the TiN(001) substrate, the process was simulated using the molecular dynamics (MD) method with the 2NN-MEAM (nearest-neighbor modified embedded atom method) potential. The results revealed that the growth mode of TiN film is determined by incident energy. When the incident energy is low, the deposited atoms have weak mobility after momentum transfer with the substrate and cannot fill the vacancy in the TiN film, and thus the TiN film eventually grows in an island shape. When increasing the incident energy, the vibration of atoms on the deposited surface is intensified, and some atoms on the film surface jump. Therefore, the non-thermal diffusion occurs, resulting in defect reduction on the TiN film and forming a lamellar growth with a more continuous and complete film. The growing incident energy continuously reduces the surface roughness of the TiN film. Full article

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14 pages, 4980 KiB

Open AccessArticle

Effect of High-Temperature Annealing on Raman Characteristics of Silicon Nanowire Arrays

by Shanshan Wang and Yan Zhang

Coatings 2023, 13(4), 793; https://doi.org/10.3390/coatings13040793 - 19 Apr 2023

Cited by 2 | Viewed by 1484

Abstract

We demonstrate two distinct experimental processes involving the large-area growth of ordered and disordered silicon nanowire arrays (SiNWs) on a p-type silicon substrate using the metal-assisted chemical etching method. The two processes are based on the etching of monocrystalline silicon wafers by randomly [...] Read more.

We demonstrate two distinct experimental processes involving the large-area growth of ordered and disordered silicon nanowire arrays (SiNWs) on a p-type silicon substrate using the metal-assisted chemical etching method. The two processes are based on the etching of monocrystalline silicon wafers by randomly distributed Ag films and ultra-thin Au films with ordered nano-mesh arrays, respectively, wherein the growth of SiNWs is implemented using a specific proportion of a HF-containing solution at room temperature. In this study, the microstructural change mechanisms for the two morphologically different arrays before and after annealing were investigated using Raman spectra. The effects of various mechanisms on the observed Raman scattering peak’s deviation from symmetry, redshift and broadening were analyzed. The evolution of the unstable amorphous structures of nanoscale materials during the high-temperature annealing process was observed via high-resolution scanning electron microscope (SEM) observations. The scattering peak parameters determined from the Raman spectra led to conclusions concerning the various mechanisms by which high-temperature annealing influences the microstructures of the two morphologically different SiNWs fabricated on the p-type silicon substrate. Therefore, the deviation of SiNWs from the monocrystalline silicon scattering peak at 520.05 cm⁻¹ when changing the diameter of the nanowire columns was calculated to further analyze the effect of thermal annealing on Raman characteristics. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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13 pages, 1841 KiB

Open AccessArticle

Quantification of Cyclo-di-BADGE and Identification of Several BADGE Derivatives in Canned Food Samples

by Juana Bustos, Antía Lestido-Cardama, Mª Isabel Santillana, Raquel Sendón, Perfecto Paseiro Losada and Ana Rodríguez Bernaldo de Quirós

Coatings 2023, 13(4), 792; https://doi.org/10.3390/coatings13040792 - 19 Apr 2023

Cited by 2 | Viewed by 2182

Abstract

Most cans intended to come into contact with food require the application of an internal coating made from synthetic polymers. The most widely used type of coating are epoxy resins based on bisphenol A diglycidyl ether (BADGE). It has been found that some [...] Read more.

Most cans intended to come into contact with food require the application of an internal coating made from synthetic polymers. The most widely used type of coating are epoxy resins based on bisphenol A diglycidyl ether (BADGE). It has been found that some components like cyclo-di-BADGE (CdB) and other BADGE derivatives can migrate into food. In this study, the polymeric coating of forty-eight cans was assessed using an infrared spectrometer with attenuated total reflectance. The food samples were extracted, and a targeted analysis was carried out to quantify CdB using liquid chromatography with fluorescence detection (HPLC-FLD). The first estimation of the exposure of the adult population was estimated by combining the concentration of CdB in the samples and the Spanish consumption data. In addition, a non-targeted screening by LC-MS was performed in the food sample extracts for the identification of other BADGE derivatives. Twenty samples were positive for the presence of CdB reaching concentrations of 2623 µg/kg. However, the tolerable daily intake of 1.5 µg/kg bw/day recommended for chemical compounds with high toxicological risk was not exceeded. A total of 18 epoxy oligomers could be tentatively identified in the food extracts being BADGE.H₂O.BuEtOH the derivative with the highest incidence. Full article

(This article belongs to the Special Issue Trends in Sustainable Food Packaging and Coatings)

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13 pages, 4476 KiB

Open AccessArticle

Study on High and Low Temperature Performance of Mineral Powder Modified Rubber Asphalt Mortar

by Weichao Liu, Ce Zhang, Lingyun Li, Lianfang Wang, Lipeng Wang, Changyu Pu and Guangqing Yang

Coatings 2023, 13(4), 791; https://doi.org/10.3390/coatings13040791 - 19 Apr 2023

Cited by 2 | Viewed by 1381

Abstract

With the increase of coal mining in China, a large amount of waste coal gangue is produced. How to reuse waste coal gangue is an important research direction. The research results showed that the improvement of base asphalt mortar by coal gangue powder [...] Read more.

With the increase of coal mining in China, a large amount of waste coal gangue is produced. How to reuse waste coal gangue is an important research direction. The research results showed that the improvement of base asphalt mortar by coal gangue powder could improve the performance of matrix asphalt, however, search of rubber asphalt mortar modified by coal gangue powder is rarely reported. High and low-temperature performance is the critical performance of asphalt mortar. So the limestone powder modified base asphalt mortar (LPMBAM), limestone powder modified rubber asphalt mortar (LPMRAM), and coal gangue powder modified rubber asphalt mortar (CGPMRAM) are prepared, the high and low-temperature performance of asphalt mortar are analyzed by cone penetration tests and bending beam rheological tests (BBR). The results show that the cone penetration of asphalt mortar decreases with the increase of the filler-asphalt ratio and the decrease of the temperature. The shear strength and the stiffness modulus increase with the rise in the filler-asphalt ratio and the decrease in temperature. At the same filler-asphalt ratio and temperature, the order of cone penetration is CGPMRAM < LPMRAM < LPMBAM, and the order of shear strength is CGPMRAM > LPMRAM > LPMBAM, so the high-temperature performance of CGPMRAM is better than that of LPMRAM, much better than LPMBAM, the order of stiffness modulus is LPMRAM < CGPMRAM < LPMBAM so the low-temperature performance of LPMRAM and CGPMRAM is better than that of LPMBAM. By the double linear model, the optimum filler-asphalt ratio is determined to be 0.44~0.46 for LPMRAM and 0.42~0.43 for CGPMRAM. Microscopic tests show that the surface of coal gangue powder is rougher than that of limestone powder. The content of active oxides such as SiO₂ and Al₂O₃ in coal gangue is about 7.8 times that of limestone powder. These physical and chemical properties make coal gangue powder able to adsorb rubber asphalt better and improve the high-temperature performance of CGPMRAM while slightly worsening the low-temperature performance of CGPMRAM but still better than LPMBAM. Full article

(This article belongs to the Special Issue Asphalt Pavement: Materials, Design and Characterization)

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12 pages, 2740 KiB

Open AccessArticle

Self-Supporting Conductive Polyaniline–Sodium Alginate–Graphene Oxide/Carbon Brush Hydrogel as Anode Material for Enhanced Energy in Microbial Fuel Cells

by Yuyang Wang, Huan Yang, Jing Wang, Jing Dong and Ying Duan

Coatings 2023, 13(4), 790; https://doi.org/10.3390/coatings13040790 - 19 Apr 2023

Cited by 2 | Viewed by 1684

Abstract

Microbial fuel cells (MFCs) have exhibited potential in energy recovery from waste. In this study, an MFC reactor with a polyaniline–sodium alginate–graphene oxide (PANI–SA–GO)/carbon brush (CB) hydrogel anode achieved maximum power density with 4970 mW/m³ and produced a corresponding current density of [...] Read more.

Microbial fuel cells (MFCs) have exhibited potential in energy recovery from waste. In this study, an MFC reactor with a polyaniline–sodium alginate–graphene oxide (PANI–SA–GO)/carbon brush (CB) hydrogel anode achieved maximum power density with 4970 mW/m³ and produced a corresponding current density of 4.66 A/m², which was 2.72 times larger than the MFC equipped with a carbon felt film (CF) anode (1825 mW/m³). Scanning electron microscopy indicated that the PANI-SA-GO/CB composite anode had a three-dimensional macroporous structure. This structure had a large specific surface area, providing more sites for microbial growth and attachment. When the charging-discharging time was set from 60 min to 90 min, the stored charge of the PANI-SA-GO/CB hydrogel anode (6378.41 C/m²) was 15.08 times higher than that of the CF (423.05 C/m²). Thus, the mismatch between power supply and electricity consumption was addressed. This study provided a simple and environment-friendly modification method and allowed the prepared PANI–SA–GO/CB hydrogel anode to markedly promote the energy storage and output performance of the MFC. Full article

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12 pages, 4414 KiB

Open AccessArticle

Preparation and Properties of Flame Retardant and Antistatic Foamed Wood–Plastic Composite with APP/ZB System

by Zhitao Lei, Jie Liu, Yating Zhao, Xuesong Zhao and Qi Li

Coatings 2023, 13(4), 789; https://doi.org/10.3390/coatings13040789 - 18 Apr 2023

Cited by 2 | Viewed by 1663

Abstract

With the aggravation of fire and smoke pollution, it is urgent to develop green, lower-cost and high-performance Foamed Wood–Plastic Composite (FWPC) to meet the standards of antistatic and flame retardant in practical application. Therefore, the flame retardant and antistatic FWPCs were prepared by [...] Read more.

With the aggravation of fire and smoke pollution, it is urgent to develop green, lower-cost and high-performance Foamed Wood–Plastic Composite (FWPC) to meet the standards of antistatic and flame retardant in practical application. Therefore, the flame retardant and antistatic FWPCs were prepared by compression molding in this study. High-density polyethylene (PE-HD) and Salix wood flour were used as main raw materials, and azodicarbonamide (AC) was used as foaming agent; Nano-carbon black (Nano-CB) was used as antistatic filler, and ammonium polyphosphate (APP) and zinc borate (ZB) were used as flame retardants. The static bending strength and elastic modulus of FWPC-20 were up to 30.01 MPa and 2636 MPa, respectively, which can meet the commercial application of wood–plastic decorative board. The logarithm of surface resistivity and volume resistivity of FWPC-20 was kept at eight, indicating that it has antistatic effect. The residual carbon rate of FWPC-20 increased to 38.58% at 800 °C, indicating that FWPC had high thermal stability. The minimum heat release rate of FWPC-20 was 226.75 kw/m², and the average heat release rate was 110.53 kw/m². The total heat release was 66.96 MJ/m², and the Limit Oxygen Index was 27.3%, which indicated that FWPC-20 had flame retardant and smoke suppression effects. This study provides a low-cost and simple method for the design of flame retardant, antistatic and high-performance FWPC, and has broad application prospects in the fields of packaging and construction. Full article

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9 pages, 1853 KiB

Open AccessCommunication

Mesogenic Units Containing Polymer Electrolytes for Light and Safe Batteries

by Lei Zhang, Yuchao Li, Shi Wang and Qian Wang

Coatings 2023, 13(4), 788; https://doi.org/10.3390/coatings13040788 - 18 Apr 2023

Viewed by 1517

Abstract

As the core component of solid-state lithium-ion batteries (SSLIBs), the bottleneck of solid-state electrolyte is to achieve fast lithium-ion transport, high electrochemical stability, and mechanical flexibility. Polymer electrolytes offer the possibility of constructing solid-state electrolytes with the above features due to their excellent [...] Read more.

As the core component of solid-state lithium-ion batteries (SSLIBs), the bottleneck of solid-state electrolyte is to achieve fast lithium-ion transport, high electrochemical stability, and mechanical flexibility. Polymer electrolytes offer the possibility of constructing solid-state electrolytes with the above features due to their excellent molecular designability. This preview highlights novel mesogenic (or liquid crystal)-containing polymer electrolytes (MPEs) exhibiting a combination of high ionic conductivity, high electrochemical stability, and mechanical flexibility. Insights into such MPEs enabling light and safe SSLIBs are also discussed. Full article

(This article belongs to the Special Issue Advanced Research on Energy Storage Materials and Devices)

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14 pages, 2288 KiB

Open AccessEditor’s ChoiceArticle

Linear and Nonlinear Optical Properties of Iridium Nanoparticles Grown via Atomic Layer Deposition

by Paul Schmitt, Pallabi Paul, Weiwei Li, Zilong Wang, Christin David, Navid Daryakar, Kevin Hanemann, Nadja Felde, Anne-Sophie Munser, Matthias F. Kling, Sven Schröder, Andreas Tünnermann and Adriana Szeghalmi

Coatings 2023, 13(4), 787; https://doi.org/10.3390/coatings13040787 - 18 Apr 2023

Cited by 4 | Viewed by 2742

Abstract

Nonlinear optical phenomena enable novel photonic and optoelectronic applications. Especially, metallic nanoparticles and thin films with nonlinear optical properties offer the potential for micro-optical system integration. For this purpose, new nonlinear materials need to be continuously identified, investigated, and utilized for nonlinear optical [...] Read more.

Nonlinear optical phenomena enable novel photonic and optoelectronic applications. Especially, metallic nanoparticles and thin films with nonlinear optical properties offer the potential for micro-optical system integration. For this purpose, new nonlinear materials need to be continuously identified, investigated, and utilized for nonlinear optical applications. While noble-metal nanoparticles, nanostructures, and thin films of silver and gold have been widely studied, iridium (Ir) nanoparticles and ultrathin films have not been investigated for nonlinear optical applications yet. Here, we present a combined theoretical and experimental study on the linear and nonlinear optical properties of iridium nanoparticles deposited via atomic layer deposition (ALD). Linear optical constants, such as the effective refractive index and extinction coefficient, were evaluated at different growth stages of nanoparticle formation. Both linear and nonlinear optical properties of these Ir ALD coatings were calculated theoretically using the Maxwell Garnett theory. The third-order susceptibility of iridium nanoparticle samples was experimentally investigated using the z-scan technique. According to the experiment, for an Ir ALD coating with 45 cycles resulting in iridium nanoparticles, the experimentally determined nonlinear third-order susceptibility is about χ_Ir⁽³⁾ = (2.4 − i2.1) × 10⁻¹⁷ m²/V² at the fundamental wavelength of 700 nm. The theory fitted to the experimental results predicts a 5 × 10⁶-fold increase around 230 nm. This strong increase is due to the proximity to the Mie resonance of iridium nanoparticles. Full article

(This article belongs to the Special Issue Optical Properties of Crystals and Thin Films)

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4 pages, 201 KiB

Open AccessEditorial

Advances in Friction-Induced Vibration in Applied Engineering

by Zilin Li and Shangwen He

Coatings 2023, 13(4), 786; https://doi.org/10.3390/coatings13040786 - 18 Apr 2023

Cited by 1 | Viewed by 1962

Abstract

Friction plays a crucial role in various engineering fields, including advanced manufacturing, transportation, aerospace, and bioengineering [...] Full article

(This article belongs to the Special Issue Recent Advances on Friction-Involved Dynamics)

10 pages, 3556 KiB

Open AccessCommunication

Spectral Imaging of UV-Blocking Carbon Dot-Based Coatings for Food Packaging Applications

by Benedetto Ardini, Cristian Manzoni, Benedetta Squeo, Francesca Villafiorita-Monteleone, Paolo Grassi, Mariacecilia Pasini, Monica Bollani and Tersilla Virgili

Coatings 2023, 13(4), 785; https://doi.org/10.3390/coatings13040785 - 18 Apr 2023

Cited by 6 | Viewed by 2257

Abstract

Nowadays, there is an increased demand to develop alternative non-plastic packaging to be used in the food industry. The most popular biodegradable films are cellulose and poly(lactic acid) (PLA); however, there is still the need to increase their UV absorption to protect the [...] Read more.

Nowadays, there is an increased demand to develop alternative non-plastic packaging to be used in the food industry. The most popular biodegradable films are cellulose and poly(lactic acid) (PLA); however, there is still the need to increase their UV absorption to protect the packaging content. In this work, we have covered those biodegradable films with thin coatings based on carbon dots (CDs) dispersed in polyvinyl alcohol (PVA) deposited by spin- or spray-coating techniques. We report a strong increase in the UV light-absorbing properties, together with a detailed morphological characterization; moreover, we show the results of a new microscopy and spectral imaging technique applied to the coated samples. The scientific and technological novelty of this approach is the possibility of characterizing large areas of the material surface by the simultaneous detection of PL spectra in all the pixels of a highly spatially-resolved two-dimensional (2D) map of the surface. We report UV-excited PL maps whose detailed information allows us to clearly identify regions with different spectral behaviors and to compare their characteristic signals for different CDs:PVA deposition techniques. Full article

(This article belongs to the Special Issue Multifunctional Coating for Packaging Applications)

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8 pages, 2102 KiB

Open AccessCommunication

The Photochemical Stability of PbI₂ and PbBr₂: Optical and XPS and DFT Studies

by Ivan S. Zhidkov, Azat F. Akbulatov, Alexander I. Poteryaev, Andrey I. Kukharenko, Alexandra V. Rasmetyeva, Lyubov A. Frolova, Pavel A. Troshin and Ernst Z. Kurmaev

Coatings 2023, 13(4), 784; https://doi.org/10.3390/coatings13040784 - 18 Apr 2023

Cited by 5 | Viewed by 2687

Abstract

We investigated the photochemical stability of PbX₂ (X = I and Br) halides by optical and X-ray photoelectron spectroscopy (XPS). The optical absorbance displayed a strong reduction for PbI2 with light soaking and permanent behavior for PbBr₂. The XPS survey [...] Read more.

We investigated the photochemical stability of PbX₂ (X = I and Br) halides by optical and X-ray photoelectron spectroscopy (XPS). The optical absorbance displayed a strong reduction for PbI2 with light soaking and permanent behavior for PbBr₂. The XPS survey spectra showed a sharp drop in the I:Pb ratio for PbI₂ from 1.63 to 1.14 with exposure time from 0 to 1000 h while for PbBr2, it remains practically unchanged (1.59–1.55). The measurements of the XPS Pb 4f and Pb 5d spectra have shown the partial photolysis of PbI₂ with the release of metallic lead whereas PbBr₂ demonstrated remarkable photochemical stability. According to the density functional theory (DFT), calculations of the metal and iodide vacancy formation energies for PbBr₂ are higher than for PbI₂ which confirms the better stability to light soaking. The high photochemical stability of PbBr₂ means that it can be used as excess under MAPbBr₃ perovskite synthesis to improve not only the power conversion efficiency but also stability to light soaking. Full article

(This article belongs to the Section Surface Engineering for Energy Harvesting, Conversion, and Storage)

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10 pages, 4213 KiB

Open AccessArticle

An Investigation into Electrodeposited Co−Ni−TiO₂ Films with Improved Mechanical and Corrosion Properties

by Yuxin Wang, Zengcheng Miao, Songlin Zheng, Jiahuan Chen and Zhen He

Coatings 2023, 13(4), 783; https://doi.org/10.3390/coatings13040783 - 18 Apr 2023

Cited by 4 | Viewed by 1547

Abstract

This investigation proposes the use of sol-enhanced electrodeposition to create a range of Co−Ni−TiO₂ films. The addition of TiO₂ sol controls the nucleation process and the properties of the composite films by generating TiO₂ nanoparticles in situ in the electrodeposition [...] Read more.

This investigation proposes the use of sol-enhanced electrodeposition to create a range of Co−Ni−TiO₂ films. The addition of TiO₂ sol controls the nucleation process and the properties of the composite films by generating TiO₂ nanoparticles in situ in the electrodeposition process. The transmission electron microscopy (TEM) and zeta potential analyses revealed a relatively homogenous distribution with particle size in the range below 100 nm for the TiO₂ nanoparticles produced. Microstructure, phase composition, hardness, friction, and corrosion resistance of Co−Ni−TiO₂ films were thoroughly investigated in relation to TiO₂ sol concentration. The results show that the addition of a limited content of TiO₂ sol upgraded Co−Ni films by producing a Co−Ni−TiO₂ film with a high dispersion of TiO₂ nanoparticles. On the other hand, too much TiO₂ sol could cause agglomeration and hinder the metal deposition process, resulting in surface pores and the deterioration of film performance. Full article

(This article belongs to the Topic Environmental Sensitivity and Safety Assessment of Materials)

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9 pages, 3843 KiB

Open AccessArticle

Fabrication of a Flower-like Copper Oxide Film-Coated Nanoporous Stainless Steel Using Anodization-Assisted Electrodeposition as a Novel Antibacterial Material

by Hefeng Wang, Naiming Lin, Jiaojiao Zhang, Yiwei Jia and Hongting Zhao

Coatings 2023, 13(4), 782; https://doi.org/10.3390/coatings13040782 - 18 Apr 2023

Cited by 1 | Viewed by 1833

Abstract

In this study, flower-like copper oxide film was prepared on the surface of 316L nanoporous stainless steel (Cu/NPSS) by anodization-assisted electrodeposition. The prepared NPSS and Cu/NPSS were evaluated with Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and X-ray diffractometer (XRD). Based [...] Read more.

In this study, flower-like copper oxide film was prepared on the surface of 316L nanoporous stainless steel (Cu/NPSS) by anodization-assisted electrodeposition. The prepared NPSS and Cu/NPSS were evaluated with Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and X-ray diffractometer (XRD). Based on local use of common diseases, the antibacterial activity of Cu/NPSS against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was investigated. The diameters of the as-formed nanopores were about 93 nm at 50 V. Cu film was successfully deposited on the surface of NPSS. The presence of Cu and O was detected in the surface of Cu/NPSS by EDX analyses. The results obtained for Cu/NPSS revealed a marked antibacterial ability. The growth inhibition rates of Cu/NPSS against E. coli and S. aureus were 99.6% and 97.4% within 12 h, respectively. This may be because of the small size and high surface-to-volume ratio of the material in addition to the release of metal ions in solution. Accordingly, Cu/NPSS will help broaden promising applications in fields of biomedical implants and devices. Full article

(This article belongs to the Special Issue Surface Treatments for Stainless Steels)

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15 pages, 3323 KiB

Open AccessArticle

Effects of Organic Additives on Alkaline Non-Cyanide Zinc Electroplating

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

Coatings 2023, 13(4), 781; https://doi.org/10.3390/coatings13040781 - 18 Apr 2023

Viewed by 2889

Abstract

We investigated the effects and interactions of the organic additives Polyquaternium-2 (PUB) and 1-benzyl pyridinium-3-carboxylate (BPC) in alkaline non-cyanide zinc electroplating. As PUB and BPC were added, the cathode potential of the polarization curve shifted in the negative direction at the same current [...] Read more.

We investigated the effects and interactions of the organic additives Polyquaternium-2 (PUB) and 1-benzyl pyridinium-3-carboxylate (BPC) in alkaline non-cyanide zinc electroplating. As PUB and BPC were added, the cathode potential of the polarization curve shifted in the negative direction at the same current density that occurred in the electrochemical experiment, and as confirmed by a scanning electron microscopy, the particles on the plating surface in the zinc deposits became finer, and the grain size decreased. Moreover, strong (101) and (002) peaks appeared in the X-ray diffraction pattern when no additive was added. However, as PUB and BPC were added, the intensity of the two peaks decreased, and an increase in the intensity of the (100) peak changed to a crystallographic orientation. With the addition of PUB and BPC, the gloss and whiteness gradually increased, and the surface roughness decreased. Finally, the throwing power tended to increase as PUB and BPC were added. Full article

(This article belongs to the Section Corrosion, Wear and Erosion)

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14 pages, 12713 KiB

Open AccessArticle

The Effect of Structure and Mechanical Properties Change of Current Collector during Cycling on Sb-Based Lithium-Ion Batteries’ Performance

by Songnan Zhao, Weijia Meng, Genwei Wang, Chunli Guo, Shengguo Ma, Zhipeng Lei, Yuanyuan Li, Meiqing Guo and Hui Song

Coatings 2023, 13(4), 780; https://doi.org/10.3390/coatings13040780 - 17 Apr 2023

Cited by 2 | Viewed by 1877

Abstract

Here, we investigate structure and mechanical change of Cu and Al current collector during cycling and analyze the contribution to capacity attenuation of Sb-based lithium-ion batteries (LIBs). There exists migration of C, Sb, and Li atoms to the inside of Cu current collector, [...] Read more.

Here, we investigate structure and mechanical change of Cu and Al current collector during cycling and analyze the contribution to capacity attenuation of Sb-based lithium-ion batteries (LIBs). There exists migration of C, Sb, and Li atoms to the inside of Cu current collector, and diffusion of Li, Co, and O atoms to the inside of Al current collector during cycling, which results in the formation of a porous film of Li₂SbCu (with the thickness of 21 µm after 100 cycles) and a relatively dense film of Al₂O₃ (with the thickness of 23 µm after 100 cycles) on the surface of Cu and Al current collector, respectively. The formation of films results in a weak bond between active layer and current collector, and the increase of hardness of 0.84 GPa and modulus of 22.5 GPa for Cu current collector after 100 cycles, which is adverse to the charge capacity and cycling stability. Nevertheless, Al₂O₃ films caused hardness decrease of 0.53 GPa and modulus decrease of 18.93 GPa of Al current collector after 100 cycles, which contributes to the improvement of cycling stability and charge capacity. This study provides an understanding of the capacity loss of Sb-based LIBs from the perspective of structural degradation of current collectors. Full article

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15 pages, 14515 KiB

Open AccessArticle

Microstructure and Properties of Al-Based Ceramic Coating Deposited on Magnesium Alloy Surface by Cold Spraying

by Shiwei Ci, Ting Wang, Jiaqi Hu, Zonghui Cheng, Suijie Xie, Xiaoye Cai, Dingping Dong, Chao Fan, Qingwei Liu, Chenfeng Yuan, Wenbo Du, Guofeng Han, Sheng Zhu, Dexin Chen and Qiwei Wang

Coatings 2023, 13(4), 779; https://doi.org/10.3390/coatings13040779 - 17 Apr 2023

Cited by 1 | Viewed by 2207

Abstract

In this study, pure Al and Al-Al₂O₃ composite coatings with a low porosity and high density were prepared on magnesium alloys by cold spraying. The surface morphology, component, hardness, interfacial bonding, wear and corrosion properties were investigated. Additionally, the relationship [...] Read more.

In this study, pure Al and Al-Al₂O₃ composite coatings with a low porosity and high density were prepared on magnesium alloys by cold spraying. The surface morphology, component, hardness, interfacial bonding, wear and corrosion properties were investigated. Additionally, the relationship between the interface structure and the protective coatings’ quality was preliminarily established. Pure Al powder was used to create a coating with a homogeneous and dense microstructure. The hard-phase Al₂O₃ in the composite coatings was non-oxidized and would reduce the porosity of the coatings to improve their density and interfacial bonding by up to 55.82 MPa. The bonding mode of the pure Al coatings is primarily mechanical, whereas the bonding mode of the Al-Al₂O₃ mixed coatings is mechanical and metallurgical. The tough Al₂O₃ particles combined to form a layer of work-hardening reinforcement that resisted wear and effectively prevented it from spreading. The three Al-based coatings had excellent corrosion properties, as evidenced by their corrosion current being several orders of magnitude lower than that of the magnesium alloy substrates. The thick coating was significantly more corrosion-resistant than the thin coating and provided greater protection to the substrate. This study offers theoretical and technological assistance for the surface protection of magnesium alloy equipment in demanding conditions. Full article

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