Journal of the Australian Ceramic Society最新文献

This study presents the development of a vinyl ester-based composite reinforced with bagasse microfibers and biocarbon derived from Moringa oleifera husks, aimed at enhancing mechanical properties, dielectric permittivity, and EMI (Electromagnetic Interference) shielding effectiveness for potential applications in electric vehicle systems. First the biomass extracted biocarbon was prepared by under slow pyrolysis technique. The composite fabrication was carried out using a hand layup method with careful mixing of biocarbon from Moringa oleifera husks and uniform dispersion of bagasse microfibers, ensuring enhanced composite performance.Further, to evaluate their performance, as per ASTM standard the composite specimen is cut under abrasive water jet machine. Based on the result obtained, the composite specimen, VB2, with 2 vol.% biocarbon and 40 vol.% bagasse microfibre, exhibited superior tensile strength (135 MPa), flexural strength (155 MPa), and hardness (83 Shore-D), due to optimal filler-matrix interaction and effective stress transfer. Dielectric permittivity was also highest for VB2, reaching 6.1 at 8 GHz, and maintaining higher values across other frequencies, indicating strong interfacial polarization. For EMI shielding, VB2 achieved the highest total shielding effectiveness of 31.5 dB at 8 GHz and 68.25 dB at 18 GHz, driven by the combined effects of enhanced absorption and reflection through synergistic filler effects. SEM analysis confirmed that VB2 had a uniform dispersion of fillers, minimizing voids and agglomerations, which is crucial for maximizing mechanical strength and electromagnetic shielding. The sustainable use of natural fibers and biocarbon also highlights the environmental benefits of this composite for automotive applications, such as battery temperature control and wireless charging in E-vehicles.

AlN ceramics are widely used in power electronics packaging due to their excellent thermal conductivity. In order to prepare AlN ceramics with good mechanical properties and thermal conductivity, 0–3 wt% Si₃N₄ was doped and annealed at 1600 °C. The effects of Si₃N₄ doping and annealing on the microstructure, thermal conductivity, and mechanical properties of the fabricated AlN ceramics were investigated. The study demonstrated that the incorporation of Si₃N₄ resulted in the generation of Y₂Si₃O₃N₄ and SiAl₄O₂N₄, which not only refined the AlN grains but also enhanced the strength of the grain boundary phase, ultimately enhanced the hardness and fracture toughness of the ceramic samples. Furthermore, the annealing process facilitated AlN grain growth and improved the crystallinity of the grain boundary phase, which increased the thermal conductivity of the AlN ceramics. Notably, after the annealing process, 0.5 SiN samples exhibited a 37% increase in thermal conductivity, and a concurrent 30% increase in fracture toughness and a 23% increase in hardness, reaching 4.2 MPa·m^1/2 and 12.8 GPa, respectively. Finally, this study explores the mechanism of Si₃N₄ doping in order to modulate the properties of AlN ceramics by changing the liquid phase composition.

The effects of the addition of 0–4 wt% nano MgO and 0–2 wt% nano SiO₂ (with respect to cement content) on hydration, microstructural, and compressive/flexural strength of Self-Compacting Concrete (SCC) were investigated. Two different post-treatment conditions with water and CO₂ gas were used to study the processing method on the samples. The results of rheological tests showed that the addition of nanoparticles decreased the flowability of SCC. The results of the density showed that the sample containing 4 wt% of MgO processed in the water environment had the lowest density and the sample processed in the CO₂ environment had the highest density. In the samples containing SiO₂ nanoparticles, an increase in density was observed with the increase of SiO₂ nanoparticles in both cases. It was also determined the amount of heat released for the samples with nano MgO was higher than the samples with nano SiO₂, which can be attributed to the heat of the hydration reaction of MgO or the formation of calcium carbonate. The mechanical properties of the samples were investigated. The compressive strength significantly improved after the addition of MgO/SiO₂ nanoparticles. However, this improvement was more remarkable in the case of post-treatment with CO₂ compared to the samples fabricated with water. SEM results showed that the samples treated under CO₂ gas had irregular and needle-like morphology. The samples prepared by normal processing had CaCO₃ and SiO₂ phases, whereas the ones fabricated under CO₂ gas contained CaCO₃, SiO₂, and Ca(OH)₂. With the addition of nano MgO, the density of concrete decreases in the samples post-treated with water, whereas it increases for the samples post-treatment with CO₂ gas. Adding nano MgO-SiO₂ to concrete and further post-treatment with CO₂ for 45 days could increase the mechanical properties.

The energy renovation of residential stock has an important contribution to carbon reduction, and building insulation systems not only require good thermal performance, but also long-term performance and durability. In particular, glazed foam ceramics are often employed for external wall insulation systems. Although artificial accelerated aging tests are often conducted to study the durability of such kind of composites, experimental research on natural and artificial aging of foam ceramics is still at its early stage. In this work, the aging tests consisting of 80 hot-rain cycles and 8 months of natural aging were carried out on foam ceramics. Special attention was paid to their compressive strength, tensile strength, compressive modulus of elasticity, bonding tensile strength, and bonding shear strength. The results revealed that the compressive strength and tensile strength of foam ceramics were not significantly affected by aging. Moreover, the bonding shear strength between ceramics and adhesives has drastically increased, while that between adhesives and cement has dropped, indicating the damage risks of the interface. Besides, the acceleration rate of the bonding tensile aging strength of foamed ceramics was found to be 12.16, while that between adhesives and cement was 5.44. The findings of this research provide the innovative experimental data on the aging of foam ceramics, but also inspiration for further study of artificial aging acceleration rate.

A thin coating of Hydroxyapatite (HAp) on implants greatly enhances bone ingrowth and osseointegration. Developed a film made of 30 wt% Laevistrombus Canarium Seashell (LCS) HAp fillers, combined with polyvinyl alcohol (PVA) and cross-linked with polyethylene glycol (PEG). Fourier Transform Infrared Spectroscopy (FTIR) analysis showed various functional groups including CH, C = C, C-O, Ca₃, PO₄, and C-Cl, in the LCS HAp/PVA/PEG film. X-ray diffraction (XRD) analysis identified the (hkl) parameters as (100), (111), (101), and (200) with a crystal size of the fillers measured at 10.15 nm. The dispersion and surface morphology of the film were examined using a Field Emission Scanning Electron Microscope (FESEM). Energy-dispersive X-ray (EDX) analysis identified the chemical composition in atomic wt%, highlighting elements such as C, O, P, and Ca, with respective percentages of 19.04, 53.68, 12.33, and 21.04. Thermal stability was evaluated using Thermal Gravimetric Analysis (TGA) and Derivative Thermogravimetric analysis (DTG), which indicated that the thermal stability of the film slightly exceeds that of pure PVA and PEG. The yield tensile stress and modulus of elasticity of the film was found 5.35 MPa and 0.35 GPa, respectively. Lastly, Atomic Force Microscopy (AFM) analysis provided insights into the surface texture, revealing a mean average roughness (Ra) of 12.28 μm for the film.

In this work sodium alginate and nano-bioactive glass (NBG) were used to create a hydrogel for tissue regeneration. Initially, a pure alginate hydrogel (ALG) and a nano-bioactive/alginate hydrogel (NBG/ALG) were created. The present approach is carried out to assess the performance of hydrogel after incorporating of NBG relative to the ALG-based hydrogel. The NBG was prepared using the sol-gel technique whereas the hydrogels were developed through chemical cross-linking. The crystalline behavior and functional groups of the NBG were examined using X-ray diffraction (XRD) and Fourier transforms infrared spectroscopy (FTIR) with and without immersion in phosphate buffer saline (PBS). The reactivity of NBG was tested in-vitro using a PBS solution at different days of immersion. The hydrogels were characterized using XRD, pH, scanning electron microscopy (SEM), FTIR, tensile, and swelling test. The NBG was tested in-vitro using PBS solution at different days. The NBG showed amorphous pattern with slight crystallinity. The in-vitro testing of NBG revealed increase in pH of PBS solution which decreases gradually. After immersion in PBS, slight peak shift was observed due to phosphate buffer. The SEM micrographs of pure ALG showed slight irregularities on the surface which removed after the incorporation of NBG with uniformly distributed nanoparticles. The addition of NBG in ALG reduced the tensile strength, elongation and elastic modulus relative to pure ALG. The NBG/ALG hydrogel swells relatively more as compared to pure ALG (5.49 vs. 3.95) % which decreased afterwards.

The purpose of this research is to investigate the synergistic effect of ZrO2 and different additives (Nano carbon black (C.B_n), graphene oxide (GO), and graphene (Gr)) on the microstructure and mechanical properties of B4C ceramic. Four composites were fabricated using the Spark Plasma Sintering (SPS) method at 2000 °C with a 15-min holding time and a pressure of 30 MPa. Relative density, hardness, and fracture toughness were measured by Archimedes’ principle, micro Vickers hardness testing, and crack length measurement, respectively. Microstructural investigations and phase identification were also evaluated by Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD). The results indicated that during sintering, all ZrO2 reacts with B4C, leading to the in-situ synthesis of the new ZrB2. Thermodynamic evaluation revealed the synthesis temperature decreases by approximately 100 °C in the presence of C.B_n/GO/Gr additives. The highest relative density (99.4%) was obtained in the sample containing C.B_n. The introduction of ZrO2 and C.B_n/GO/Gr additives resulted in a decrease in the hardness of B4C decreases. The highest fracture toughness (5.7 MPa m^0.5) was obtained in the sample containing GO, while the lowest was observed in the sample without C.B_n/GO/Gr additive (3.9 MPa m^0.5). Examination of the crack path propagation showed that the activation of toughening mechanisms such as crack deviation and branching are the main reason for the enhanced fracture toughness in the sample containing GO.

In this paper we investigate the impact of ZrO₂ and TiO₂ as nucleating agents on the crystallization behavior of a lithium aluminosilicate (LAS) glass–ceramic (G-C). The crystallization mechanism is explored at first through X-ray diffraction analyses next to various heat treatments. Differential scanning calorimetry (DSC) analyses conducted under non-isothermal conditions at different heating rates reveal well-defined exothermic peaks. The activation energy (Ea), the key parameter in understanding thermal kinetics, is determined through model-free methods, specifically Flynn Wall Ozawa (FWO) and Kissinger Akahira Sunose (KAS), as well as the model-fitting approach (Coats-Redfern, C–R method). Additionally, the crystallization mechanism of the studied LAS glass ceramic is discussed utilizing the C–R method and Criado’s methods. By employing these techniques, a comprehensive analysis of the LAS glass–ceramic system is provided, contributing to the fundamental understanding of its crystallization processes, and laying the groundwork for further advancements in G–C materials.

The exceptional magnetic properties of magnetite and Fe₃O₄ nanoparticles make them the most intensively reported inorganic nanomaterials in cancer research. Here, Fe₃O₄ nanoparticles were prepared by the chemical co-precipitation method and loaded with dual chemotherapeutic drugs, methotrexate (MTX) and SN38 (Fe₃O₄-SN38-MTX), to achieve tumor-targeting potency and elevate the dual therapeutic antitumor efficacy towards the breast cancer cells. The synthesized Fe₃O₄ nanoparticles exhibit excellent magnetic hyperthermic performance (MHT) because of their superparamagnetic behavior and attain saturation magnetization at 66.37 emu/g. Moreover, the double drug conjugation of Fe₃O₄ nanoparticles exhibits enhanced MHT efficiency due to its dual-chemotherapy performance. The successful preparation of Fe₃O₄-SN38-MTX nanoparticles was confirmed by XRD, FTIR, and UV-visible studies. Additionally, the magnetic property was investigated using SQUID, and their Fe₃O₄-SN38-MTX nanoparticles’ cytotoxic performance was evaluated by CCK-8 analysis of L929 and 4T1 cells. As a result, the prepared Fe₃O₄-SN38-MTX nanoparticles exhibit 64% tumor cell death via combinational therapy (MHT/CT) than single therapy.

The aim of this study was to investigate the two-and three-body friction and wear characteristics of three different dental composites (flowable bulkfill, single shade, and conventional composites) in artificial saliva and poppy seed slurry. Tribological tests were performed using a reciprocating ball-on-flat-type tribometer according to ASTM-G133. The tested composites exhibited clear differences in terms of their wear and friction behaviors depending on their hardness, microstructure, and test media. The results showed that conventional and single-shade composites may have more positive results in posterior teeth because of their more durable wear characteristics, especially in two-body wear, whereas an additional capping layer using a wear-resistant dental composite with improved tribological behavior is necessary to finish the restorations when using flowable bulkfill composite.