Journal of the Australian Ceramic Society最新文献

Calcium silicate-based cement, such as mineral trioxide aggregate (MTA), are widely recognized as effective root-filling materials due to their biocompatibility, sealing ability, and bioactivity. However, its relatively low mechanical strength limits its application in clinical practices. This shortcoming can be addressed by modifying its structure, particle size and optimizing the synthesis temperature to enhance material properties. The formation of tricalcium silicate (C₃S), a key crystalline phase responsible for the material’s binding strength, occurs at high temperatures. Therefore, calcination temperature is a critical factor influencing the mechanical properties of MTA. Here, we synthesized MTA using calcium oxide derived from natural sources (clam shell) combined with nano silica at calcination temperatures of 900 °C, 1000 °C, and 1100 °C. The MTA exhibited stability at a minimum calcination temperature of 1000 °C, with optimal characteristics at 1100 °C. The MTA synthesized at 1100 °C demonstrated a compressive strength of 12.41 ± 0.09 MPa, a diametral tensile strength of 6.33 ± 0.22 MPa after 14 days of hydration, and a radiopacity value of 7.82 ± 0.28 mmAl. The synthesized material maintained an alkaline pH and a stable release of calcium ions from the 7th day of immersion. These findings underscore the importance of optimizing particle size, synthesis temperature, and tricalcium silicate formation to address the limitations of conventional MTA and highlight the potential of nMTA-1100 as a biocompatible material with enhanced mechanical properties for endodontic applications.

Globally, the importance of using less dense and bio-based compound in domestic and transport vehicles applications are increased, because of reducing the usage of fossil fuel and petro chemical based product. The utilization of less dense material improves reduced fuel consumption, which eventually reduced global emission. Thus the present study developed a lightweight composite material using bamboo fiber, and barnyard millet husk extracted Bio ceramic particle. The primary goal of this research is to investigate and analyze mechanical, fatigue, creep, water absorption and wear resistance of surface modified and angle oriented bamboo fiber and varying concentrations of Si₃N₄ reinforced vinyl ester composites. Results observed that, composite VBS1 with 40 vol% of oriented fiber, 1 vol% of Si₃N₄particle shows better mechanical properties such as 178.2 ± 1.8 MPa for tensile, 225 ± 2.6 MPa for flexural, 6.32 ± 1.6 J for impact strength. On contrast, the specimen VBS2 with 3 vol% Si₃N₄ attained least fatigue life counts of 28,743 at 50% UTS, creep strain of 0.0040 at 5000s, 0.0089 at 10000s and 0.0190 at 15000s, wear resistance with Specific Wear rate of 0.32 mm³/Nm and Coefficient of friction (COF) of 0.26. Similarly, in terms of water absorption, the specimen VB with 40 vol% fiber shows least water absorption of 0.21% compared to filler reinforced composites. Moreover, the SEM analysis offers insignificant insights on the in depth microstructure of the composites. Due to such great benefits and properties, these composite acts as a suitable replacement to synthetic materials in various kinds of applications including outer body parts in automotive, aviation sector, construction, interior and exterior works such as furniture and kitchenware etc.

Concrete has been a cornerstone of construction for centuries, but its environmental impact necessitates the development of sustainable alternatives. Ceramic-modified concrete (CMC) offers a promising solution by incorporating waste ceramics, yet accurately predicting its mechanical properties remains challenging due to the material's heterogeneous composition. Traditional methods, such as linear regression and finite element modeling (FEM), often fail to capture the complex interactions between ceramic content and concrete performance, resulting in suboptimal prediction accuracy and limited generalizability. To address these limitations, this study proposed the CMC-MRGCN-TTAO framework, which leveraged an optimized Multidimensional Refinement Graph Convolutional Network (MRGCN) combined with the Triangulation Topology Aggregation Optimizer (TTAO). Experimental results demonstrate that incorporating 20% ceramic waste as a partial replacement yielded the optimal mechanical performance, achieving a 28.4% improvement in compressive strength (from 39 to 50 MPa) and a 34.7% increase in tensile strength (from 4.5 MPa to 6.1 MPa) after 28 days of curing compared to conventional concrete. The proposed model outperformed traditional machine learning and deep learning methods, with an R² of 0.99 and low RMSE values, making it a reliable tool for sustainable construction material optimization.

Transition metal oxide electrocatalysts have gained attention for their potential in eco-friendly electrochemical applications, due to their affordability, durability, structural adaptability, and customizable catalytic activity. This study integrates 5d transition metal oxide nanoparticles MoO₃ with a porous FeTe array on nickel foam to form the MoO₃@FeTe/NF porous nanosphere array. This structure achieves low overpotentials of 42 mV for the hydrogen evolution reaction (HER) and 222 mV for the oxygen evolution reaction (OER) at 10 mA cm^− 2, with OER and HER Tafel slopes of 108 mV dec^− 1 and 66 mV dec^− 1, respectively, demonstrating stability over 25 h during HER testing, and 80 h for OER. The MoO₃@FeTe/NF nanocatalyst also reaches a current density of 10 mA cm^− 2 with a cell voltage of 1.5 V. This research presents an effective method for creating cost-effective electrocatalysts for water-splitting applications.

Composite materials are receiving growing attention due to their diverse industrial applications and environmentally friendly characteristics. This study presents the synthesis of an innovative polyvinyl alcohol-based composite reinforced with cobalt ferrite nanoparticles derived from grape peel extract. The aim is to explore the potential of such composites as alternatives to synthetic materials in sectors such as the aerospace, construction, automotive, and marine industries. Polyvinyl alcohol served as the matrix, while cobalt ferrite, synthesized from grape peel extract and crystallized through heat treatment at 400 °C, was used as the reinforcement. Among the prepared samples, the composite containing 1% volume of cobalt ferrite exhibited the best mechanical performance, with a tensile strength of 62 MPa (a 37.8% increase compared to the unreinforced sample), a tensile modulus of 2.1 GPa (40% higher), a tear strength of 33 N/mm, and a Shore-D hardness of 33. In contrast, the composite with the highest cobalt ferrite content showed the lowest specific wear rate (0.018 mm³/N·m), a coefficient of friction of 0.27, thermal conductivity of 0.65 W/m·K, and the highest dielectric permittivity (5.0) and dielectric loss (0.78). It also exhibited a contact angle of 68°, indicating improved hydrophobicity. These results demonstrate the effectiveness of this natural filler-reinforced composite for use in various high-performance engineering applications.

This study investigates the surface properties of zirconia fabricated via nano particle jetting (NPJ), a material jetting–based additive manufacturing (AM) technique, and compares them to conventionally milled (CM) zirconia following plasma surface treatment. AM zirconia discs were produced using a 3 mol% yttria-stabilized ZrO₂ slurry, while CM discs were prepared from semi-sintered blocks. Both sample types were sintered at 1500 °C, ground, and subjected to low-pressure, low-temperature air plasma treatment for 1 or 5 min. Initial grain sizes were 0.545 ± 0.211 μm for AM and 0.520 ± 0.214 μm for CM zirconia, and X-ray diffraction confirmed the preservation of the tetragonal phase after treatment. Surface roughness parameters remained within the nanometer range and were unaffected by plasma exposure. As-built water contact angles were 59.1° ± 8.6° for AM and 58.9° ± 9.0° for CM zirconia, indicating comparable inherent hydrophilicity. Plasma treatment effectively reduced carbon residues and enhanced surface wettability by lowering the contact angles to 14.5° ± 3.1° (AM) and 15.7° ± 2.2° (CM) after 1-min treatment. However, no significant differences were observed with longer treatment durations. The effect was sustained for at least 72 h in closed storage but reverted after 2 months in ambient conditions. Vickers hardness of AM zirconia was 1298 ± 13 HV1.0, which was lower than that of CM zirconia (1341 ± 8 HV1.0) and plasma treatment had no measurable effect on surface hardness. This is the first study to systematically compare NPJ-manufactured and milled zirconia under standardized plasma conditions. The findings demonstrate the feasibility of NPJ zirconia for dental applications and the potential of plasma surface modification to improve early-stage biological responses through enhanced wettability.

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Efficient and stable semiconductor photocatalysts are crucial for environmental and energy applications but often suffer from limited visible light absorption and rapid charge recombination. In this study, Eu-doped ZnS and CdS nanoparticles were synthesized via a co-precipitation method followed by calcination at 300 °C to enhance crystallinity. Europium was incorporated at 5 mol% to investigate its effects on structural, optical, and photocatalytic properties. XRD and XPS analyses confirmed successful Eu incorporation, inducing lattice distortions and defect states. SEM revealed reduced particle size and increased agglomeration. Optical studies showed redshifted absorption edges and narrowed band gaps (ZnS: 3.10 → 2.95 eV; CdS: 2.75 → 2.60 eV), indicating improved visible-light absorption. PL measurements revealed Eu³⁺-related emissions and suppressed electron-hole recombination. Photocatalytic tests demonstrated enhanced Rhodamine B degradation under visible light, with Eu-doped CdS achieving 95% efficiency after five reuse cycles. Eu doping effectively tunes the optoelectronic properties of ZnS and CdS, enhancing their performance for photocatalysis, wastewater treatment, and light-emitting applications.

This research aims to develop a vinyl ester-based nanocomposite with enhanced thermal and barrier properties by integrating silicon nitride (Si₃N₄) and granite dust fillers with silane treated form. The primary objective of this research is to develop sustainable composite using waste materials. The vinyl ester resin was chosen for its favourable properties in vacuum infusion and casting processes. Moreover, Si₃N₄ particles were extracted from peanut husk through a medium temperature pyrolysis and nitration process with a size of 180 nm. Along with this the granite dust was also used as filler. Both the fillers undergo surface-modification process using 3-aminopropyltrimethoxysilane (APTMS) to enhance interfacial bonding. The composites were fabricated using solution casting method, with precise control over the mixing and curing parameters. Among various composite specimens, N4 composite contains 2 vol% of Si₃N₄, showed improved load bearing effect. Moreover, it achieved a highest mass loss stability of 99% at 415 °C due to the excellent thermal resistance of Si₃N₄. However, composite N4 also recorded the highest thermal conductivity at 0.42 W/mK, demonstrates its ability to efficiently dissipate heat. Although its water absorption was slightly higher up to 0.3%, it remains within acceptable limits for composites. In barrier property tests, composite N4 displayed a water permeability of 5.57% and an oxygen permeability of 2.63 × 10⁻² cc/m².d.atm, indicating that, despite a slight increase in water permeability, N4 effectively limits oxygen diffusion due to its ceramic-based structure. These results suggest that the composite offers a robust combination of thermal and barrier properties, making it a promising candidate for advanced coating applications where heat resistance and barrier performance are critical.

The present study investigated the impact of applying an electric field during the initial stage of low-carbon steel continuous casting or the casting of high-carbon steel, focusing on the interface behavior between molten steel and the submerged entry nozzle under the external electric field. The results showed that carbon-containing substances continuously dissolved at the interface and entered the molten steel, altering the wettability. This led to enhanced adhesion and solidification of the molten steel on the inner wall of the submerged entry nozzle, which accelerated the formation of clogging. Applying an external electric field could control and enhance the interface contact, wetting, and reaction behavior between the submerged entry nozzle and molten steel during the continuous casting. The contact angle under negative electric fields was generally higher than that under positive electric fields, given the influence of different polarity conditions. By selecting appropriate electric field application parameters based on specific continuous casting conditions, the quality and production efficiency of steel materials can be effectively improved.