Journal of the Australian Ceramic Society最新文献

Al₂TiO₅ has received widespread attention due to its lower thermal conductivity in materials with a low coefficient of thermal expansion. Therefore, white fused corundum, tabular corundum and micro α-Al₂O₃ were selected as alumina sources to prepare Al₂TiO₅ by in-situ synthesis in this paper. The influence of alumina sources on the phase compositions, microstructure and thermal conductivity of the samples was investigated. The mechanism of the in-situ synthesis of Al₂TiO₅ was discussed in detail. The results showed that increasing the sintering temperature was beneficial for the formation of Al₂TiO₅. Besides, adding white fused corundum or tabular corundum was conducive to the preparation of Al₂TiO₅. The liquid phase formed by a small number of impurities in the raw materials at high temperatures could accelerate the diffusion velocity of Al³⁺ and Ti⁴⁺, which was beneficial to the formation of Al₂TiO₅ and the stability of its structure. The sample with tabular corundum sintered at 1600 °C had the highest content of Al₂TiO₅ about 86 wt%, and the largest average grain size of 35.3 μm. It also showed satisfactory performance, with the bulk density of 2.99 g/cm³ and the compressive strength of 98.5 MPa. Moreover, the thermal conductivity at 900 °C was reduced to 0.96 W/(m·K) compared to the sample without tabular corundum, which could be used to prepare Al₂TiO₅ ceramics with lower thermal conductivity.

This study presents the formulation and evaluation of composite bioinks incorporating synthetic hydroxyapatite (CSHA), sheep-derived hydroxyapatite (SHA), and alumina (Al₂O₃) for extrusion-based 3D bioprinting of bone scaffolds. Rheological analyses demonstrated shear-thinning behavior, with both CSHA/Al₂O₃ and SHA/Al₂O₃ exhibiting comparable viscosity profiles between 400 and 1000 s⁻¹, indicating their suitability for stable extrusion. The bone scaffolds were fabricated using a single-syringe extrusion-based bioprinter. After the printing process, the scaffolds were dried and then immersed in simulated body fluid (SBF) to evaluate their in vitro bioactivity. This immersion process was carried out under static conditions at 36.5 °C for 28 days. SEM and EDS analyses revealed denser apatite nucleation on CSHA/Al₂O₃ scaffolds (Ca/P = 1.33) compared to SHA/Al₂O₃ (Ca/P = 0.88), confirming enhanced bioactivity. FTIR analysis detected characteristic phosphate and carbonate bands indicative of bone-like apatite formation. Cell viability and cytocompatibility were assessed using MTT and WST-1 assays with L929 fibroblasts and osteoblasts. While fibroblast viability showed no significant difference (p > 0.05), CSHA/Al₂O₃ scaffolds promoted significantly higher osteoblast viability (p < 0.05). Confocal microscopy confirmed sustained osteoblast proliferation at 36 h. These findings demonstrate that CSHA/Al₂O₃-based bioinks possess favorable printability, mineralization potential, and osteogenic support, making them strong candidates for future bone tissue engineering applications using ceramic-reinforced bioprinting strategies.

Yttria stabilized zirconia (YSZ) is becoming increasingly popular in the field of dental biomaterial due to its faster production process, reduced preparation thickness, and lower cost. This study aims to compare the experimentally obtained gamma-ray absorption coefficients for YSZ dental biomaterial with theoretical data generated through GAMOS simulation and Phy-X/PSD software. The minimal µ value is determined to be 0.274 cm^–1 at an energy of 1408 keV. The µ/ρ values for the 662 keV gamma ray, derived from experimental data, GAMOS simulation, and the Phy-X/PSD algorithm, are 0.070, 0.072, and 0.074 cm²/g, respectively. As gamma energy escalates, both the half-value layer and the tenth-value layer also increase. Comparable results are obtained from both the experimental data and the datasets generated by Phy-X/PSD and GAMOS. The mean free path value is measured to be 3.645 cm using 1408 keV photons. The experimentally obtained data show good agreement with the results obtained from the GAMOS simulation and the Phy-X/PSD program.

The invention relates to the sustainable development of undoped and doped nickel oxide nanoparticles (NiO-NPs) using Zephyranthes citrina bulb extract as a bio-reductant in a solution combustion synthesis process. NiO NPs were synthesized by doping them with varying amounts of zirconium (Zr) and neodymium (Nd), enhancing their crystallinity and allowing precise control over their optical properties. Structural and morphological characteristics were confirmed using distinctive techniques. These analyses validated the NPs’ integrity, surface features, and band gap modifications. Their biological activities were assessed, including antioxidant, anti-inflammatory, antimitotic (onion root tip assay), and antidiabetic effects. Additionally, their agronomic potential was evaluated through seed germination and seedling growth studies. This environmentally friendly synthesis provides a viable path for developing NiO NPs suitable for optoelectronic and biomedical applications.

Graphical Abstract

In order to achieve the goals of decarbonization and sustainable development, this study select iron tailings, fly ash, and ceramic powder (IFC) to prepare ternary solid-waste admixtures with multiple ratios. Different Ca(OH)₂ dosages and cement substitution rates are investigated to research the activation mechanism, aiming to resolve difficulties in activating multiple solid wastes added as supplementary cementitious materials and improve the concrete pore structure. Besides, multiple water to binder ratios, admixture dosages and mixing ratios of IFC are attempted to research the effect on concrete compressive strength for 7 days and 28 days of curing (7D and 28D). In addition, the fineness of iron tailings (IOTs) powder is tested for both research targets above. To further study the micro morphology of IOTs particles and pore structures of the prepared concrete, scanning electron microscope (SEM), mercury intrusion porosimetry (MIP) and backscattered electron imaging (BSE) are applied. The results show that IFC ternary solid waste admixture with high activity could accelerate hydration process of cement matrix, and the inert and unhydrated particles would also exert ‘micro-aggregate effect’, ‘nucleation effect’ and ‘dispersion effect’ to help promote strength of concrete.

Impedance spectroscopy was applied to determine the simultaneous effect of the cement hydration time and internal moisture on the electrical properties of cement composites with expanded graphite content within the percolation zone and above the percolation threshold. Impedance spectroscopy was used for electrical properties measurements of cement pastes to 90 days of hydration for different moisture content. Measurements were made in a frequency range of 5 to 13 MHz. Nyquist plots were prepared from the data obtained and appropriate electrical equivalent circuits were fitted. Then, resistivity and capacitance values of the composites were calculated from the fitted equivalent circuits. The results showed influence of hydration time on electric properties of cement composites with EG content in percolation zone. For these composites, impedance spectra change with hydration time. The resistivity values increase with the hydration time, whereas the capacitance decreases. Spectra include two semicircles, whereas spectra consist of vertical lines for a lower saturation degree. The lower the water content, the change in the nature of the reactance occur at shorter hydration time. Instead, no changes were observed for composites with EG above the percolation threshold.

In this study, Mn- and Ni-doped MoO₃ thin films were synthesized using a sol–gel spin coating method and evaluated as photoanodes in dye-sensitized solar cells (DSSCs). Structural, morphological, optical, and electrochemical properties of the films were systematically analyzed using XRD, SEM, UV–Vis spectroscopy, and electrochemical impedance spectroscopy (EIS). Doping with Mn and Ni resulted in a reduction in crystallite size, improved optical absorption in the UV–visible range, and enhanced electrical conductivity. The photovoltaic performance of DSSCs incorporating the doped films demonstrated a significant improvement, with power conversion efficiencies increasing from 2.4% for pristine MoO₃ to 3.375% and 5.0% for Mn- and Ni-doped films, respectively. EIS analysis revealed that Ni doping yielded the lowest charge transfer resistance (~ 15 Ω), highlighting its superior catalytic activity and electron transport capabilities. These results underscore the potential of Mn- and Ni-doped MoO₃ thin films in advancing DSSC technologies.

The primaryscope of the research is to develop and investigate the properties and performance of the composites as a uniquetactic in the material science field. This research investigates the mechanical, thermal, and machinability properties of an epoxy composite reinforced with basalt and bamboo fibers, incorporating varying concentrations of chitin. The optimized composite, EBT3 (4 vol% chitin), demonstrated superior load-bearing capacity, with fatigue life counts of 24,711, 21,711, and 18,741 cycles at 25%, 50%, and 75% UTS, respectively. Additionally, its creep behaviour exhibited minimal deformation, with values of 0.0064, 0.0069, and 0.0095 at 5,000, 10,000, and 15,000 s, indicating enhanced adhesion and interfacial bonding. In contrast, the EBT4 composite (8 vol% chitin) exhibited reduced flame propagation speed (5.31 mm/min), moderate hydrophobicity (67.52° water contact angle), and improved machinability, as evidenced by narrower kerf widths of 5.06 mm and 10.09 mm for 5 mm and 10 mm drill bits, respectively. The higher chitin content contributed to increased hydrophilicity, enhanced structural integrity, and greater thermal stability, influencing these properties. SEM analysis further provided insights into fiber-matrix bonding, filler dispersion, and agglomeration effects. Given their exceptional properties, these composites hold potential for marine, prosthetic, drone, automotive, and packaging applications.

This study investigates the enhancement of PLA-based composites through the incorporation of biosilica particles extracted from proso millet husk. The primary aim of this study is to analyse how the addition of proso millet husk derived biosilica performs in the load bearing behaviour. To evaluate this, customized filaments contains varying biosilica were produced and fabricated into composite plates via 3D printing. According to results, among the tested samples, specimen A3 (2 wt% biosilica) exhibited the best mechanical performance, attributed to uniform filler dispersion and strong matrix-filler bonding. Moreover, composite A3 showed the longest fatigue life counts of 39.9 × 10³ for 75% of ultimate tensile stress. In terms of wear performance, composite A4 (4 wt% biosilica) demonstrated the lowest specific wear rate (0.043 mm³/Nm) and coefficient of friction (0.3), although it also recorded the highest water absorption (0.27%), indicating increased hydrophilicity. SEM analysis confirmed good filler dispersion at lower biosilica content, while higher loading led to particle agglomeration. These results suggest that biosilica-reinforced PLA composites offer promising potential for eco-friendly, high-performance applications in fields such as biomedical devices, automotive components, drones, and construction materials.

This work presents an analysis of the effect of BaO incorporation on the gamma-ray attenuation properties of systematically evaluated SiO₂-B₂O₃-SrO-ZrO₂ glass matrices. Radiation shielding parameters determined using XCOM and EGS4 calculation codes were compared. There was an increase in glass density from 5.84 g/cm³ to 6.32 g/cm³ when the BaO content rose from roughly 10% to 40%. Using sophisticated WinXCom and EGS-4 calculations, the mass attenuation values (µ/ρ) of BaO doped SiO₂-B₂O₃-SrO-ZrO₂ glass systems (abbreviated BaSiBSZ) were found. This study systematically and thoroughly evaluated the effect of BaO integration on the radiation shielding capabilities of the glass system over a wide range of gamma-ray photon energies, specifically between 59.5 keV and 1332 keV. Initially, HVL (half-value layer) and MFP (mean free path) values were derived from the calculated mass attenuation coefficients. The evaluation of several crucial shielding parameters, including RPE, Z_eff, ΣR, and (k_gamma) , came next. The steady reduction of SrO oxide concentration and substitution of BaO in BaSiSBZ glass systems resulted in notable modifications in radiation protection properties. The BaSiBSZ glass systems showed a similar decrease in both HVL and MFP at a constant energy level as the BaO doping concentration was progressively raised. Concurrently, a notable enhancement was noted in RPE, Z_eff, Σ_R, and (k_gamma) coefficients. The results demonstrate that higher BaO concentrations greatly enhance the material's radiation-shielding capabilities, enhancing both photon and neutron attenuation and bolstering the overall performance of the glass system.