Ceramics

The ceramic and glass industries, integral to the EU Emissions Trading System (EU ETS), face significant challenges in achieving decarbonization despite advancements in energy efficiency. The circular economy offers a promising pathway, emphasizing the reuse and recycling of waste materials into secondary raw materials (SRMs) to reduce resource consumption and emissions. This study investigates a standardized waste supply chain framework, developed collaboratively with stakeholders, tailored for the ceramic sector. The Waste Resource Platform (WRP) integrates Industry 4.0 paradigms, utilizing a modular, layered architecture and a process-centric design. The framework includes experimental tests and co-creation methodologies to refine a digital marketplace that connects stakeholders, facilitates SRM exchange, and fosters industrial symbiosis. The WRP demonstrates the potential for SRMs to replace virgin materials, reducing environmental impacts and production costs. It enhances supply chain transparency through digital traceability, promotes predictive material sourcing, and streamlines logistics via algorithmic optimization. Challenges such as regulatory gaps and quality standards are addressed through standardized processes, open data governance, and innovative algorithms. The WRP project advances circular economy goals in the ceramic sector, promoting waste reuse, industrial symbiosis, and supply chain resilience. Its standardized, open-access platform offers a scalable model for other industries, fostering sustainable practices and resource efficiency while addressing global climate targets. Full article

This study investigates the effectiveness of replacing the cement with 0, 5, 10, 15, and 20 wt.% of ceramic waste powder (HCCP) to improve the performance of recycled aggregate concrete (RCA) prepared using 25 wt.% wall tile ceramic coarse aggregates. The slump, initial and final setting time, compressive strength, splitting tensile strength, flexural strength, electrical resistivity, bulk density, porosity, total and surface water absorption, pH level, ultrasonic pulse velocity, dynamic elastic modulus, chloride ion diffusion coefficient, chloride penetration depth, microstructure analysis, and environmental assessment properties were investigated. The results showed that replacing cement with HCCP by 5 to 20 wt.% prolonged the setting time and improved all hardened properties. The highest improvements in mechanical properties were observed at 5 wt.% HCCP, with increasing rates of 26.5%, 22%, and 22.4% at 90 days for compressive strength, tensile strength, and flexural strength, respectively. On the other hand, the optimum enhancement for the durability, microstructural, and environmental efficiency properties was recorded at a 20 wt.% HCCP replacement rate. However, the strength at this ratio tended to decrease but remained higher than that of the control RAC. For instance, the total water absorption, surface water absorption, void ratio, chloride penetration depth, and migration coefficient were reduced by 47%, 45%, 38%, 62.3%, and 55.52%, respectively, compared to the reference sample. Full article

The process of creating ceramic items using fused deposition modelling (FDM) enables the creation of intricate shapes for a variety of purposes, including tooling and prototyping. However, due to the numerous variables involved in the process, it is challenging to discern the impact of each parameter on the final characteristics of FDM components, which impedes the advancement of this technology. This paper deals with the application of statistical analysis in the study of the dependence of the flexural strength of sintered zirconia disks on the printing parameters (nozzle diameter, layer thickness, and infill pattern) of the fused deposition method printing of a ceramic–polymer filament containing 80 wt.% zirconia and 20 wt.% polylactide. X-ray-computed tomography and diffraction systems, scanning electron microscopy combined with energy-dispersive spectroscopy, were used for a microstructural analysis of the sintered samples. It was found that the nozzle diameter and infill pattern have no significant influence on the flexural strength values. It was assumed that this is due to the heterogeneous distribution of the ceramic phase in the manufactured filament during extrusion. On the other hand, correlation analysis and analysis of correlation diagrams have shown that the thickness of the filling layer has the greatest effect on flexural strength. The maximum (684 МPa) strength value was found in a sample printed with a layer thickness of 0.2 mm. The minimum layer thickness ensures a more uniform distribution of ceramic particles and minimizes defects in samples that occur during FDM printing. The results obtained make it possible to optimize the considered process of manufacturing ceramic products from ZrO₂ printed using FDM technology from extruded composite filaments. Full article

Limestone Calcined Clay Cement (LC³) has become a highlighted research topic over the past decade. Through various research, LC³ demonstrated the capability to supplement portions of cement, highlighting the possibility to decrease CO₂ emissions due to the low calcination temperatures and low levels of CO₂ released from the material during calcination. At this stage, there is no research into the feasibility of LC³ in any parts of Australia, limited research in finding clay, and incomplete research understanding how low calcination temperatures affect the compressive strength. The results show the feasibility of LC³, where we demonstrated the feasibility of a low calcination temperature of 650 °C and found that various overburden waste clays (clay in quarries and mines that are not needed) across the East Coast of Australia produced comparable compressive strength results to conventional Portland cement-based mixes. The results also indicate that optimising the particle size distribution of the calcined clay enhanced both the workability and compressive strength of the mortars. Full article

Hybrid layered reinforced materials are able to increase the reliability, durability, and expand the functionality of high-temperature components in supercritical and ultra-supercritical power plants and in oil, gas, and petrochemical equipment operating under conditions with multifactorial influences (temperature, force, deformation). As a result of this research, surface reinforced ceramic composite materials with a gradient distribution of properties have been developed. These materials include thermal barrier layers (Gd₂O₃-Yb₂O₃-Y₂O₃-ZrO₂) and Ni-based layers reinforced with ceramic carbide and oxide particles. They are strong, have a high heat and wear resistance, and provide the specified functional and mechanical properties. The formation technology for the hybrid composites has also been developed. This technology includes the mechanical alloying of powder compositions, which is followed by vacuum plasma spraying. The structure of the powder compositions and composite layers, the density of the obtained composite materials, and the heat and wear resistance of the composites have also been investigated. The microhardness of the alloy layers of the hybrid composite materials Hastelloy X–GYYZO–material 1 and Hastelloy X–GYYZO–material 2 was as follows: super alloy Hastelloy X, HV_0.2 = 3.8–3.95 GPa; layer GYYZO, HV_0.3 = 16.1–16.7 GPa; layer material 1, HV_0.3 =18.3–18.8 GPa; layer material 2, HV_0.3 =19.1–19.6 GPa. The influence of the refractory phase of HfC and TaC on the strength of the composites was studied. It was found that the maximum strength (710–715 MPa) in the composites Hastelloy X—GYYZO—material 1 and Hastelloy X–GYYZO–material 2 is achieved with a content of HfC and TaC–27–28%. Full article

Ceramic samples of solid solutions of the binary system (1−x)BiFeO₃-xBaTiO₃ + 2 wt.% Bi₂O₃ (0.29 ≤ x ≤ 0.33, Δx = 0.01) were prepared using the conventional solid-phase reaction method with and without mechanical activation. Using X-ray studies, it was found that the objects have a pseudocubic crystal structure, and limited solubility occurs in solid solutions of the studied composition, as evidenced by the presence of regions with an increased Bi or Ba content and similar cell parameters. A diffuse phase transition occurred from the FE to PE state in the temperature ranges of (650–850) K. Relaxor-like behavior and the smearing of the phase transition in the studied ceramics can be associated with the presence of non-interacting regions with an increased content of Bi or Ba, different modulation, and crystal lattice symmetry. The grain morphology and dielectric characteristics of the selected solid solutions were investigated. The highest piezoelectric coefficient, d₃₃ = 120 pC/N, was obtained in the mechanically activated ceramics 0.71BiFeO₃-0.29BaTiO₃ + 2 wt.% Bi₂O₃. Full article

This paper introduces a method that enhances the traditional slip casting technique’s potential to fabricate ceramic objects with variable thickness. The variability depends on the different filtration rates offered by plaster moulds of varying densities. Two sets of experiments are presented. They focused on identifying (1) the maximum workable density range of moulds made from plaster of Paris and (2) the range of thickness in the resulting ceramic casts. This was accomplished by creating four square flat moulds with different gypsum/water (G:W) ratios and their corresponding casts. Based on these findings, the second set of experiments focused on assembling graded plaster moulds with variable densities (G:W 1:3 to 2:1), resulting in ceramic tiles exhibiting a thickness gradient of 2 mm. These results suggest the possibility of producing double-curved ceramic objects (e.g., custom ceramic tiles or sanitaryware) with graded thickness, tailored to their desired structural and functional performance. Full article

The ceramics industry has consistently applied circular economy principles by efficiently reusing and recovering raw materials in the production process. Incorporating secondary raw materials, such as production scraps and recycled materials, reduces costs and improves sustainability. In the ceramics sector, raw materials like feldspars can be substituted with secondary raw materials from other production processes, particularly glass-based ones. This study selected waste glass, such as bottle glass or glass fiber processing scraps, to investigate its performance in a porcelain stoneware slab mixture. The behavior of this mixture was compared to a traditional porcelain stoneware mixture and a mixture containing a glass-ceramic frit, which exhibits significantly different behavior from waste glass. The study involved a comprehensive characterization of the fired samples, with a specific focus on addressing pyroplastic deformation—an issue that occurs in large slabs during the firing process. Although pyroplastic deformation has been extensively studied in the past using various waste glasses, this research work uniquely employed waste glass fiber and glass-ceramic material to mitigate pyroplastic deformation compared to the more commonly studied waste soda–lime glass. The pyroplastic deformation tests were conducted using an instrument from Expert Lab Service-MDF. Full article

This study investigates the design and mechanical evaluation of hydroxyapatite (HAp) scaffolds for bone tissue engineering, using stereolithography (SLA) to fabricate homogeneous and hollow elongated Voronoi structures. HAp, known for its biocompatibility and biodegradability, was selected to create scaffolds with a structure that supports cell growth. Both scaffold designs were tested under compression to measure key properties, including compressive strength, Young’s modulus, stiffness, and energy absorption. The homogeneous design demonstrated superior mechanical properties, achieving a maximum load of 913.6 N at a displacement of 0.166 mm and a stiffness of 5162.8 N/mm, indicating a higher load-bearing capacity and energy absorption compared to the hollow design. Despite these strengths, failure analysis revealed early fractures at strut junctions, particularly in slender areas, leading to fluctuations in the load–displacement curve and suggesting a risk to neighboring tissues in practical applications. These findings underscore the potential of Voronoi-based scaffolds for orthopedic use, while also highlighting the need for structural refinements to improve scaffold durability and clinical effectiveness. Full article

This study explores the different techniques used to manufacture porous clay-based ceramics, examining their properties such as porosity, strength, permeability and filtration efficiency. Different techniques are discussed in this review, with additive manufacturing being one of the most innovative techniques for manufacturing porous ceramics. Porous ceramics have their applications in numerous domains. Such ceramic filters have the advantages of retaining heavy materials, suspended particles, bacteria, viruses and, water turbidity. Thus, the choice of the technique and propriety is a crucial step in obtaining a porous ceramic with the best performance. Barry et al. prepared porous phyllosilicate-based ceramics by freeze-tape casting on four samples and obtained porosity values in the range of 67–79% and diametrical compressive strength in the range of 3–7 MPa. Manni et al. prepared porous red ceramics from Moroccan clay and coffee waste (10, 20 and 30 wt.%) via uniaxial pressing and sintering at 1150 °C. They obtained porosities ranging from 30.2 to 63.8% and flexural strength values from 1.8 to 19.5 MPa. Medri et al. prepared ZrB2-based porous bodies with the use of sponges and polyurethane foams as templates via the replica method and obtained high porosity over 80% and compressive strength up to 4.8 MPa. The use of clay and peanut shell mixtures was used in preparing porous silicate ceramics after unidirectional pressing and sintering at 1100 °C. These samples included 25 mass% of peanut shells, and exhibited porosity in the range of 40 to 60% and diametrical compressive strength in the range of 1–6 MPa. Such properties are suitable for domestic use of these types of clay-based ceramic filters. Moreover, the permeability values and removal of some pollutants, like arsenic, have been satisfactory for the first set of samples. Full article

In this work, Fe³⁺- and Co²⁺-doped ZnO NPs (zinc oxide nanoparticles), Zn_0.9Fe_xCo_0.1−xO, with a hexagonal wurtzite phase (single-phase), were synthesized via a co-precipitation technique where the phase purity and elemental composition were confirmed by XRD and EDX, respectively. Due to the substitution of Fe by Co, the cell parameters ($a$ and c) were increased, alongside which a slight shift to higher diffracted angles appeared. FTIR was carried out to confirm the insertion of both the Fe³⁺ and Co²⁺ dopants into the ZnO hexagonal phase. Based on the experimental results, different numerical techniques were used to determine the optical gap and refractive index for the ZnO NP-doped samples, and when the concentration of Fe³⁺ ions was increased, the band gap value of ZnO decreased from 3.36 eV to 3.29 eV, accompanied by a decrease in the Urbach energy, while the refractive index increased. The doped ZnO NPs were later found to be effective UV photocatalysts which demonstrated a maximum reduction (84%) of methylene blue (MB) in a neutral environment for X = 0.05. The correlation between the Fe³⁺ concentration, structure, optical parameters, and photocatalytic efficacy is explained in detail. Full article

We obtained original glasses and glass-ceramics through the controlled melting and recrystallisation of basalt rocks extracted from several quarries in the Canary Islands. The electrical measurements of the resulting glasses and glass-ceramics were conducted in a complex impedance at temperatures in the 250–700 °C range. These electrical determinations made it possible to follow the nucleation and crystal growth processes. The main crystalline phases were pyroxenes, feldspar (anorthite) and magnetite, which decorate the dendritic crystallisation of pyroxenes. The magnetite is present as nanocrystals, being the component chiefly responsible for the electrical conduction properties of these glass-ceramics. Electrical conduction is facilitated by the presence of magnetite nanocrystals on the axes of dendrites of pyroxene crystals, enabling polar electron conduction in these materials. Thus, the Fe²⁺/Fe³⁺ ratio was related to the total Fe²⁺/Fe, which made it possible to express an electronic conduction model. Full article

Double perovskite materials have emerged as key players in the realm of advanced materials due to their unique structural and functional properties. This research mainly focuses on the synthesis and comprehensive characterization of Ba₂CoWO₆ double perovskite nanopowders utilizing a high-temperature conventional solid-state reaction technique. The successful formation of Ba₂CoWO₆ powders was confirmed through detailed analysis employing advanced characterization techniques. Rietveld refinement of X-ray diffraction (XRD) and Raman data established that Ba₂CoWO₆ crystallizes in a cubic crystal structure with the space group Fm-3m, indicative of a highly ordered perovskite lattice. The typical crystallite size, approximately 65 nm, highlights the nanocrystalline nature of the material. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) discovered a distinctive morphology characterized by spherical shaped particles, suggesting a complex particle formation process influenced by synthesis conditions. To probe the electronic structure, X-ray Photoelectron Spectroscopy (XPS) identified cobalt and tungsten valence states, critical for understanding dielectric properties associated with localized charge carriers. The semiconducting character of the synthesized Ba₂CoWO₆ nanocrystalline material was confirmed through UV-Visible analysis, which revealed an energy bandgap value of 3.3 eV, which aligns well with the theoretical predictions, indicating the accuracy and reliability of the experimental results. The photoluminescence spectrum exhibited two distinct emissions in the blue-green region. These emissions were attributed to the transitions ³P₀→³H₄, ³P₀→³H₅, and ³P₀→³H₆, primarily resulting from the contributions of Ba²⁺ ions. The dielectric characteristics of the compound were analyzed across a different range of frequencies, spanning from 1 kHz to 1 MHz. Magnetic characterization using Vibrating Sample Magnetometry (VSM) revealed antiferromagnetic behavior of Ba₂CoWO₆ ceramics at room temperature, attributed to super-exchange interactions between Co³⁺ and W⁵⁺ ions mediated by oxygen ions in the perovskite lattice. Additionally, first-principles calculations based on the Generalized Gradient Approximation (GGA+U) with a modified Becke–Johnson (mBJ) potential were employed to gain a deeper understanding of the structural and electronic properties of the materials. This approach involved systematically varying the Hubbard U parameter to optimize the description of electron correlation effects. These results deliver an extensive understanding of the structural, optical, morphological, electronic, and magnetic properties of Ba₂CoWO₆ ceramics, underscoring their potential for electronic and magnetic device applications. Full article

Barium silicates have been investigated as high-expansion components of solid oxide fuel cells (SOFCs) and, therefore, their synthesis and expansion have been the subject of intensive research in recent years. In this article, we briefly present a new process to make glass–crystalline composites, as well as two novel findings related to a synthesis route of sanbornite (BaSi₂O₅) and the fast in situ formation of a high-expansion sanbornite composite from a Pyrex-type glass powder. The low-temperature synthesis, composition, and expansion of one type of novel glass composite are described. The composites are made by the reaction of BaCO₃ and Pyrex-type powders at 850–950 °C for a short time of one hour. The composites are well sintered and hard, and their linear coefficient of thermal expansion is about 12.3 × 10⁻⁶ C⁻¹. The crystalline-phase formation, dilatometer measurements, SEM data, and possible applications of the composites are presented and discussed. Full article

Refractory flue walls in anode baking furnaces are exposed to harsh conditions during operation, affecting the structural properties of the material. The flue walls in industrial furnaces degrade over time to the point where they no longer perform as intended and must be replaced. Earlier studies of spent refractory lining from anode baking furnaces have shown considerable densification of the flue wall bricks, where the densification varies significantly from the anode side to the flue side of the brick. The observed densification is proposed to be caused by high-temperature creep, and the aim of this work was to determine whether the uneven densification across the brick could be modeled using a finite element method (FEM) implementing high-temperature steady-state creep. Finite element modeling was used to model steady-state creep for a material similar to that used in the baking furnace. Thermal and physical parameters and boundary conditions were chosen to simulate the conditions in an anode baking furnace. Refractory samples of pristine and spent lining from the baking furnace were also analyzed with X-ray computed tomography (CT), with a reduction in the porosity confirming the densification during operation. The FEM modeling demonstrated that high-temperature creep could explain the observed densification in the spent flue walls. The present findings may be useful in relation to increasing the lifetime of industrial flue walls. Full article

Transition (Ti, Zr) metal-substituted calcium hexaorthophosphate CaTi_4-zZr_z(PO₄)₆ coatings with an NaSICon structure were deposited by atmospheric plasma spraying (APS) onto Ti6Al4Veli substrates using a statistical design of experiments (SDE) methodology. Several coating properties were determined, including chemical composition, porosity, surface roughness, tensile adhesion strength, shear strength, and solubility in protein-free simulated body fluid (pf-SBF) and TRIS-HCl buffer solution. The biological performance evaluation involved cell proliferation and vitality studies and osseointegration tests of coated Ti6Al4Veli rods intramedullary implanted in sheep femora. After a 6 months observation time, a satisfactory gap-bridging potential was apparent as shown by a continuous, well-adhering layer of newly formed cortical bone. These tests suggest that the coatings possess a suitable osseoconductive potential and present an enhanced expression of bone growth-supporting non-collagenous proteins and cytokines, a high cell proliferation, spreading and vitality, and substantial osseointegration by strong bone apposition. The moderate intrinsic ionic conductivity of CaTi_4-zZr_z(PO₄)₆ compounds can be augmented by doping with highly mobile Na⁺ or Li⁺ ions to levels that suggest their use in electric bone growth stimulation (EBGS) devices, able to treat nonunion (pseudoarthrosis) and osteoporosis, and that may also support spinal stabilisation by vertebral fusion. Full article

High-temperature structural materials face severe degradation challenges due to oxidation and corrosion, leading to reduced long-term stability and performance. This review comprehensively examines the interfacial migration mechanisms of reactive elements (REs) such as Ti, Al, and Cr in Ni/Fe-based alloys, emphasizing their role in forming and stabilizing protective oxide layers. We discuss how these oxide layers impede ion migration and mitigate environmental degradation. Key findings highlight the importance of selective oxidation, oxide layer healing, and the integration of novel alloying elements to enhance resistance under ultra-supercritical conditions. Advanced insights into grain boundary engineering, alloy design strategies, and quantum approaches to understanding charge transport at passive interfaces are also presented. These findings provide a foundation for developing next-generation high-temperature alloys with improved degradation resistance tailored to withstand extreme environmental conditions. Full article

Thirteen porcelains assigned to Sèvres factory productions and a few references to the other contemporary factories (Chantilly, Limoges, and Venice) have been studied on-site with a portable X-ray fluorescence (pXRF) spectrometer in order to control the provenance attribution. Characteristic XRF signals of major elements (Si, Ca, K, Pb) and minor/trace (Au, Bi, As, Ti, Co, Cu, Zn, Ni, Y, Zr, Rb, and Sr) elements are compared for the paste, blue mark, various glazed (colored) areas, and gilding. The comparison of peak intensities clearly distinguishes different types of hard- and soft-paste porcelain, made from either similar or distinct raw materials. The analysis of transition elements associated with cobalt identifies three types of cobalt blue and reveals that du Barry-style decoration on certain artifacts was typical of 19th-century production. On-site comprehensive studies of the two famous Etruscan-style breast bowls from Rambouillet Castle dairy, using pXRF and Raman spectroscopy, confirm the use of soft-paste porcelain for the cup and hard-paste for its support, providing detailed information on the use of gold nanoparticles in the burgundy-colored decoration. Full article

The microwave dielectric properties of (1−x)Ca_0.6(La_0.9Y_0.1)_0.2667TiO₃-x(Nd_1/2La_1/2)(Mg_(1+δ)1/2Ti_1/2)O₃ ((1−x)CYTO-xNLMTO) ceramics were investigated in this study. It was discovered that the addition of 1 wt% CuB₂O₄ effectively enhanced the densification and improved the microwave dielectric properties of (1−x)CYTO-xNLMTO, where δ = 0.02. The new ceramic systems of (1−x)CYTO-xNLMTO could achieve ultra-low loss and a high dielectric constant. The novel ceramic systems comprising (1−x)CYTO-xNLMTO exhibited remarkably low loss and a significantly high dielectric constant. Full article