Mixed oxides with perovskite (ABO3), pyrochlore (A2B2O7) and spinel (AB2O4) structures were synthesized to studying them as potential adsorbents of environmental contaminants, including a possible reuse of the materials prepared. For materials with the perovskite structure and calcium(II) doping, the use of collagen during the synthesis subtly inhibited the formation of the solid solution, resulting in materials that were less efficient as adsorbents for removing TB from the medium. Undoped perovskite and pyrochlore adsorbents showed similar TB removal efficiencies, with undoped materials being the most effective for TB removal. Materials with perovskite and pyrochlore structures showed high efficiency in removing TB and CR from aqueous media, whereas the spinel-structured material was less effective. The efficiencies of materials as adsorbents are affected by the type and amount of metal in the structure sites, as well as by the structure itself. Despite this, all the synthesized materials showed excellent results in the cycle reuse study, maintaining TB removal efficiency throughout all cycles, with the perovskite structure standing out. They are efficient and sustainable materials for removing contaminants from synthetic solutions and industrial effluents because they are regenerable and reusable.
High-entropy borides (HEBs) are promising ultra-high-temperature ceramics (UHTCs) for extreme environments; however, their synthesis and densification remain challenging due to complex phase formation and oxygen-related limitations. In this work, the synthesis and consolidation of (MoTiNbHfTa)B2 HEB were investigated using a combined self-propagating high-temperature synthesis (SHS) and field-assisted sintering technology (FAST) approach. Two precursor strategies were comparatively studied: a fully metallic system and an oxide-containing system, together with two boron sources (B and B+MgB12). Metallic mixtures exhibited higher combustion temperatures leading predominantly to the formation of individual diborides. In contrast, oxide-containing systems promoted enhanced atomic-level mixing during in-situ reduction, favoring the formation of multicomponent boride phases despite the presence of secondary oxide-related phases. FAST consolidation resulted in relative densities of ∼80–84% for as-synthesized powders, which increased to ∼96% after particle size refinement. The fully densified material exhibited a uniform microstructure, high hardness (17.9GPa), and reduced thermal conductivity (∼13W/mK), consistent with multicomponent solid-solution formation. The results demonstrate that precursor composition plays a decisive role in controlling combustion behavior, phase evolution, and densification of HEBs, providing a viable pathway for the synthesis of dense, phase-pure UHTCs.
This study addresses the development of environmentally sustainable ceramic glazes by eliminating both lead-based compounds and commercial frits. While lead-free systems are widely investigated, frit-free formulations based on natural raw materials remain limited, particularly in terms of systematic compositional control and crystallization mechanisms. In this work, lead-free and frit-free glass-ceramic glazes were designed using Algerian raw materials within the CaO–MgO–Al2O3–SiO2–ZnO–ZrO2 system. A systematic investigation of the MgO/CaO ratio (r=0, 0.1, and 0.2) was carried out to establish its role in phase evolution and property development. The results show that the MgO/CaO ratio and firing temperature strongly influence crystallization, surface morphology, optical properties, and mechanical performance. Zircon was identified as the dominant phase, enhancing whiteness through strong light scattering. CaO-rich compositions promoted anorthite–wollastonite networks, producing matte surfaces with improved mechanical strength, whereas MgO-rich glazes increased gloss and vitrification but reduced strength. An intermediate MgO/CaO ratio provides an optimal balance between optical quality and mechanical durability, highlighting the potential of compositional tuning for designing high-performance frit-free glass-ceramic glaze.
Animal-derived hydroxyapatite (HA) is considered a promising alternative for bone applications. In this study, its production was focused on via a drilling-calcination-milling route applied to porcine femurs, aiming to identify the critical milling threshold required to transition from a polydisperse, cytotoxic material to a biocompatible nanostructure. The powders were characterized by X-ray diffraction (XRD) coupled with Rietveld refinement, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). Concurrently, the in vitro performance was evaluated in the L929 cell line using cytotoxicity and proliferation assays at 24 and 48 h. The primary particle and crystallite sizes were reduced by extended milling, shifting the material toward the nanometric regime and increasing morphological homogeneity, as was observed via SEM and TEM. A chemical composition compatible with biological HA, along with the presence of trace elements characteristic of the animal origin, was qualitatively confirmed through EDS screening. The biological assays revealed that cytotoxic HA was produced by short milling times (2 h) due to size-associated polydispersity. Conversely, non-cytotoxic nano-HA was successfully achieved through prolonged milling (6 h), corresponding to sample D-S45-M6H. A significant increase in cell proliferation was exhibited by the latter at 48 h (34.81% above the control), thereby surpassing the standard biogenic responses reported in recent literature. A sustainable and high-precision alternative to synthetic precursors is represented by this approach, as livestock waste is effectively transformed into a high-value biomaterial for advanced bone regeneration. (c) 2026 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Calcium phosphate-based bioceramics are highly valued in biomedical engineering for their remarkable biocompatibility and ability to promote bone regeneration. Hydroxyapatite (HAp) and zinc-doped R-tricalcium phosphate (xZn-TCP) have both been the subject of extensive research as biomaterials. However, the performance of composites combining these two materials still needs to be optimized. In this study, the HAp-and xZn-TCP-based composites, where x =3mol% and 5mol%, were carried out by mixing in water the two powders previously synthesized through a classical coprecipitation process. The stabilized slurries were slip cast on a plaster support to prepare thin pellets to be sintered. The study focused on two series of Zn-doped HAp/TCP composites containing HAp as the main phase (90 and 80 wt%) and xZn-TCP as the main phase (90 and 80 wt%). Structural analyses confirmed the presence of R-TCP with a rhombohedral structure and HA with a hexagonal structure. Zinc doping significantly improved sinterability, yielding relative densities of up to 99% at 1200 degrees C, particularly for the lower Zn content. Furthermore, zinc stabilized the R-TCP phase, resulting in an increase in the R-TCP -> a-TCP transition temperature to approximately 1420 degrees C. The mechanical study highlighted a positive relationship between increased sample density and optimization of material properties. Indeed, the composite made up of 80% (3 mol% Zn-TCP) and 20% HAp exhibited superior performance, showing the highest value of Young's modulus-135 GPa and the Vickers hardness-5.4 GPa. Along with these mechanical properties, cytotoxic tests performed by means of MTT assay on HEK293 cells showed that all compositions supported cell viability above 100%, thus indicating the absence of any cytotoxic effects. In addition to that, the ability to stimulate cell proliferation is another important property of these materials. Thanks to these unique properties, the materials under discussion have excellent prospects for usage in clinical practice, namely, as dental implants, spinal cages, and bone defect repair sites. (c) 2026 The Author(s). Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
Enamel coating on pipelines can be done in several ways such as the wet process, plasma spray, and electrostatic process. Wet process requires little capital expenses and provides an acceptable finish for industrial applications particularly when the part to be coated is small. Electrostatic process of enamel powder is most promising to coating large pipelines in field conditions. The enamel coating applied by the electrostatic process is very consistent and smooth since each particle is glass only. However, the powder is very fragile until fired and the charge retention is lowered in high humidity conditions. Coupons cut from a full-size steel pipe of low carbon steel using high pressure water jet were coated and enameled by Roesch Inc. and provided to Missouri University of Science and Technology for evaluation. The wet process of enamel slurry was compared with the electrostatic process to demonstrate their performances measured by coating uniformity, surface roughness, and corrosion resistance. (c) 2026 Published by Elsevier Espa na, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/
Mortars made of mixed cement and lime (mixed mortar) have good mechanical behaviour and improve adhesion to other materials. In this study, mixed mortars have been prepared and characterized with a partial replacement of 25% of the natural aggregate by recycled crushed glass. The physical and mechanical properties have been evaluated and the ultrasonic transmission rates have been determined. The Student's t-test was used to statistically analyze the outcomes. Internal structures and potential mineralogical alterations were analyzed by SEM. The characteristics of these mortars were compared with those of reference ones. The resistance results have revealed an improvement of the mixed mortar with glass compared to the reference mixed mortar of 14% in bending and 10% in compression. Moreover, a decrease in Young's modulus has been shown in mixed mortars with glass in comparison with the reference mixed mortars, although the addition of glass does not imply statistically significant differences. (c) 2026 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
The development of flexible and conformal transducer arrays is critical for next-generation underwater acoustic systems, enabling wide-beam coverage and high-fidelity signal acquisition. In this work, a novel 1-2-2-type piezocomposite integrating piezoceramics, rigid polymer, and flexible polymer is proposed, modeled, and experimentally validated for monolithic transducer array applications. An equivalent parameter model is established to reveal the relationships among ceramic volume fraction, acoustic impedance, and electromechanical coupling, leading to an optimized configuration that achieves high coupling efficiency (kt = 0.64) and low acoustic impedance (Z = 15.6 Mrayls). The composite is fabricated through a monolithic dual-dicing and dual-filling process, effectively overcoming the limitations of conventional manual assembly. Experimental results show excellent agreement with theoretical predictions, and the array exhibits outstanding element uniformity, with the relative deviation among nine elements maintained below 2%. These results confirm the superior flexibility, consistency, and integration potential of the proposed design. The 1-2-2 composite offers a robust and scalable route for high-consistency, wide-beam conformal transducer arrays, providing new opportunities for advanced underwater sonar and acoustic imaging systems. (c) 2026 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
The rapid development of 5G and 6G communication systems has created a strong demand for high-performance microwave dielectric ceramics, which are critical for supporting ultra-high-frequency signal transmission, device miniaturization, and thermal stability. Zn2SiO4 ceramics are considered promising candidates for high-frequency wireless communication and packaging technology due to their low permittivity and ultra-low loss tangent. However, achieving a near-zero temperature coefficient of resonant frequency (tau(f)) at relatively low sintering temperatures remains a significant challenge. In this study, Zn0.17Nb0.33Ti0.5O2 (ZNT) was introduced to tune the tau(f) value for Zn2SiO4 ceramics, aiming to develop Zn2SiO4-based ceramic composites with near-zero tau(f). The effects of varying Zn/Si ratios on the sintering behavior and microwave dielectric properties of 0.6Zn(2-x)SiO(4-x)-0.4ZNT (0.2 <= x <= 0.65) ceramics were systematically investigated. Optimal microwave dielectric properties of epsilon(r) = 12.75, Q & times; f = 37,182 GHz (at 10.805 GHz), and tau(f) approximate to -1.47 ppm/degrees C were obtained for the densified 0.6Zn(1.5)SiO(3.5)-0.4ZNT ceramic sintered at 1150 degrees C for 3 h. Furthermore, terahertz time-domain spectroscopy (THz-TDS) measurements in the 0.4-1.2 THz range demonstrated excellent dielectric performance, highlighting the material's potential for next-generation communication applications. The favorable microwave and terahertz dielectric properties, combined with low-temperature sintering behavior, present new opportunities for the development of high-frequency wireless communication devices. (c) 2026 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
This study investigates the effect of adding 0.1, 0.3, 0.6, 1.0, 2.0 wt.% halloysite clay, which is calcined at 600 degrees C, to the standard ceramic tableware slurry. The test specimens were fabricated by pressing of granulated compositions and subsequently sintering at 1180 degrees C for 2 h. Detailed deformation, mechanical and microstructure characterization studies were done on sintered samples. All sintered samples with halloysite exhibited higher bending strength than the standard sample. The sample with 1.0 wt.% calcined halloysite showed the highest bending strength (12.80 MPa) and the lowest pyroplastic deformation (1.15 & times; 10-5 cm-1) among all the samples. Phase analysis and microstructural investigations revealed a significant increase in needle-like mullite phases within the microstructure at this optimal halloysite concentration. These findings suggest that the augmented interlocking of mullite grains contributes to improved mechanical strength and reduced deformation. This study demonstrates halloysite addition might enhance the technological properties of conventional tableware to achieve a reduced thickness in line with current market trends and environmental considerations. (c) 2026 The Author(s). Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
The influence of (Ca2+ + Al3+) -* (La3+ + Ni2+) substitution on the color of calcium aluminates (Ca3Al2O6, CaAl2O4, CaAl4O7, CaAl12O19) obtained by combustion synthesis represented the focus of this work. The maximum temperature recorded during combustion reactions increased from 1406 degrees C to 1606 degrees C with increasing the Al3+/Ca2+ ratio. The formation of solid solutions having the same Ni2+ content (0.3 at.%) was confirmed by X-ray diffraction. Following the combustion reactions, the solid solutions derived from Ca3Al2O6, CaAl2O4 and CaAl4O7 had a gray color. After annealing at 1300 degrees C these samples showed undefined pastel shades. Increasing the Ni2+ doping level to 5 at.% relative to tetrahedral Al3+ proved that only Ni-doped hibonite crystal structure can render a blue coloration, which after annealing became slightly more intense. These results demonstrate the importance of the rational choice of the host crystal lattice: among all calcium aluminates herein investigated, hibonite was the only one that allowed obtaining blue pigments as a result of (Ca2+ + Al3+) -* (La3+ + Ni2+) substitution. (c) 2026 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
The peanut-shaped cobalt (Co)-doped zinc manganese oxide (ZMO: ZnMn2O4) was successfully synthesized via a simple solvothermal and calcination process. The effects of Co-doping concentration on the structural and electrochemical properties of the samples were examined. The novel porous Zn1-xCoxMn2O4 materials with different molar fractions relative to Zn (where x = 0, 0.15, 0.3, and 0.45) were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and nitrogen (N2) adsorption-desorption isotherms. The results demonstrated that the incorporation of Co into the ZnMn2O4 lattice did not produce any distinct secondary phases. The microparticle size and the specific surface area increased, while the energy band gap was reduced. The application of the peanut-shaped Co-doped ZnMn2O4 samples as cathode materials for zinc-ion batteries (ZIBs) was also investigated. The ZMO-0.45Co sample exhibited a larger cyclic voltammetry (CV) peak area, higher redox peak value, and lower charge transfer resistance (Rct) compared to the undoped sample (ZMO-0Co). The maximum charge and discharge capacities were 133.0 and 122.5 mAh g-1, respectively. These results suggest that the Co doping in peanut-shaped ZMO enhances charge transfer efficiency and improves the specific capacity of cathode material in ZIBs. (c) 2026 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
Sheet-type all-solid-state lithium batteries are promising candidates for large-scale energystorage applications. In particular, the use of thin sulfide-based solid-electrolyte layers can significantly reduce battery volume. However, preparing such electrolyte layers or sheets remains challenging due to the limited chemical compatibility of sulfide electrolytes with common solvents and binders. In this study, we investigate the fabrication of an argyroditetype sulfide solid-electrolyte sheet using an acetonitrile-ethanol solvent mixture and ethyl cellulose as the binder. First, we examine how the chosen solvents and binder influence the crystal phase, structure, morphology, and ionic conductivity of the electrolyte. Next, we optimize the electrolyte composition and processing parameters to achieve uniform, flexible, and highly conductive sheets via the doctor-blade method. As a result, a uniform, crack-free argyrodite solid-electrolyte layer with a thickness of approximately 5 & micro;m and an ionic conductivity of 0.23 mS cm-1 is obtained, providing a thin electrolyte layer suitable for subsequent fabrication of sheet-type all-solid-state batteries. (c) 2026 The Author(s). Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
CuO, CuWO4 and materials of copper and tungsten were prepared through simple wet chemical route. X-ray diffraction (XRD) results showed the formation of two predominant crystalline phases: CuO and CuWO4. Specifically, the materials of copper and tungsten exhibited those crystalline phases in different concentrations for each oxide. A first semi quantitative analysis allowed determine most of crystalline parameters that characterize the samples. Complementary, Fourier transform infrared spectroscopy (FTIR) analysis allowed to verify the crystalline phases formation because any vibration band associate other compound was detected. In terms of morphological properties, two different morphologies were observed: polyhedral grains associated to CuO and nanoparticles linked to CuWO4, fact that confirm the heterostructure formation. These properties were supplemented with the estimation of surface parameters and parameters of hydrodynamic stability, which induce the principle of application of the heterostructures obtained in biological applications. Then, the bactericide response was evaluated. 100:1 and 100:2 materials showed an outstanding bactericide response, due to similar structural, morphological and superficial properties, and the fact to Cu2O secondary phase was detected at a lower percentage. In this investigation the capacity of CuO/CuWO4 heterostructures in bactericide activity against Gram negative bacteria was verified. (c) 2026 The Author(s). Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
Rechargeable zinc-air batteries (ZABs) are promising for sustainable energy storage; however, their widespread application is limited by the high cost and scarcity of platinum group metal (PGM) catalysts. This study presents a novel platinum group metals- and cobalt-free bimetallic Fe/Mn catalyst, synthesized via a sol-gel method with urea and surfactants, followed by low-temperature thermal treatments. Two thermal routes were investigated: one in air and another in ammonia flow. Characterization by SEM, BET, TGA-DTA, FTIR, Raman, and XRD revealed distinct structural differences. The ammonia-treated catalyst showed a high surface area (182 m2/g) and incorporation of nitrogen and carbon into the structure, forming nitrides and graphitic carbon, which contributed to enhanced porosity and catalytic performance. Electrochemical tests confirmed bifunctional activity for both the oxygen reduction (ORR) and oxygen evolution (OER) reactions. Notably, the NH3-treated catalyst demonstrated superior long-term stability during galvanostatic cycling in a ZAB setup. These findings highlight the potential of Fe/Mn-based, PGM-free catalysts for the development of long-life rechargeable ZABs, emphasizing the beneficial role of nitrogen incorporation in improving structural stability and catalytic efficiency. (c) 2026 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
The influence of (Ca2++Al3+)→(La3++Ni2+) substitution on the color of calcium aluminates (Ca3Al2O6, CaAl2O4, CaAl4O7, CaAl12O19) obtained by combustion synthesis represented the focus of this work. The maximum temperature recorded during combustion reactions increased from 1406°C to 1606°C with increasing the Al3+/Ca2+ ratio. The formation of solid solutions having the same Ni2+ content (0.3at.%) was confirmed by X-ray diffraction. Following the combustion reactions, the solid solutions derived from Ca3Al2O6, CaAl2O4 and CaAl4O7 had a gray color. After annealing at 1300°C these samples showed undefined pastel shades. Increasing the Ni2+ doping level to 5at.% relative to tetrahedral Al3+ proved that only Ni-doped hibonite crystal structure can render a blue coloration, which after annealing became slightly more intense. These results demonstrate the importance of the rational choice of the host crystal lattice: among all calcium aluminates herein investigated, hibonite was the only one that allowed obtaining blue pigments as a result of (Ca2++Al3+)→(La3++Ni2+) substitution.
Stability and microstructure of tricalcium phosphate polymorphs (TCP) in the Ca-3(PO4)(2)-Zn-3(PO4)(2)Mg-3(PO4)(2) phase equilibria diagram from experimental studies between 1200 degrees C and 1400 degrees C have been determined. Solid-state compatibilities in the CaO-P2O5-MgO-ZnO system were defined at 900 degrees C for P2O5 <= 50% mole %, from a complete review of the previously published binary, pseudo-binary, ternary and pseudo-ternary systems and key phase diagrams experiments on CaO-P2O5-MgO-ZnO system. The phase compatibilities of TCP, without considering solid solutions, except for Mg2P2O7-Zn2P2O7 complete solid solution, were stablished and the role of MgO and ZnO on the formation of phases compatible with Ca-3(PO4)(2) was discussed.(c) 2025 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
Cobalt is essential to industrial growth, and a low-carbon economy. It is crucial to the production of lithium-ion batteries and national security. Other industrial applications are: superalloys, catalysts, hard metals, ceramics, or magnets. In particular, 5.3% cobalt demand was used in the ceramic sector in 2024, accounting for almost 12 kt. The European Union (EU) relies on imports of refined cobalt, especially from China and the Democratic Republic of the Congo. To ensure strategic autonomy, the EU aims to increase cobalt processing and recycling. This study focuses on the optimization of the leaching process to recover cobalt from spent LIBs with high efficiency and purity for sustainable use. Sulphuric, citric, and nitric acids were selected for the study, varying the concentration of the dissolution, reaction time and temperature, and the solid-to-liquid ratio. The best results were obtained using a 2 M HNO3 solution with 4 vol.% H2O2 and a 1:50 solid-to-liquid ratio, working at a temperature of 85 degrees C for 60 min. The applicability of the recovered cobalt oxide was assessed by its use in the synthesis of a ceramic blue pigment. (c) 2025 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
This work presents the first systematic archaeometric data of 13th-14th century AD Nasrid glazed architectural ceramics from the Alhambra and Generalife, focusing on colour-specific glazing technologies. Findings provide new insights into Nasrid glazing technology, ceramic typologies, and conservation implications, contributing to discussions on Islamic material culture and technical traditions in al-Andalus. Analysed typologies include mosaic, inlay, relief tiles, roof lights, and steles with glazes in white, blue, green-turquoise, black, and honey tones. Microstructural and chemical results reveal decorative chromophores and techniques to be a reference for future studies. Most glazes are inglaze on lead tin-opacified bases, fired in oxidising conditions at similar to 950 degrees C. Phosphorus was found in weathered glazes (associated with a burial environment) and unweathered white and blue glazes, suggesting deliberate addition of bones (fragments/ashes). Identified phases in most glazes were unmelted quartz and feldspars grains, and relatively abundant Cr-bearing wollastonite crystals precipitated during firing. Furthermore, one of the fragments with a black surface was determined not to be a glaze, but rather a polished section of a metamorphic rock. (c) 2025 The Authors. Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).
