Journal of the Australian Ceramic Society最新文献

Hydroxyapatite (HAp) is a biomaterial that has been extensively studied for its exceptional biocompatibility, osteoconductivity and non-toxic nature, making it highly suitable for applications in bone and dental tissue engineering. This review evaluates the incorporation of metallic ions into the HAp lattice as a strategic approach to optimize its structural integrity, mechanical performance and biological functionality. Quantitative findings from recent studies show that Ag⁺ doping at 1 wt% reduces bacterial growth by over 95%, but higher doses ( > 3 wt%) can reduce cell viability by up to 20%. Sr^{2 +} (5 wt%) improves bone regeneration by 25%, though excessive levels may alter lattice stability. Zn^{2 +} at 3 wt% enhances osteoblast proliferation by 60% but can slightly reduce thermal stability. Cu^{2 +} improves angiogenesis and antimicrobial efficacy, but high concentrations can induce cytotoxicity. Furthermore, metallic ion doping enhances the dielectric properties and contributes to anti-cancer capabilities, expanding HAp’s therapeutic potential. The review also highlights advanced applications of metallic ion-doped HAp, including its role in drug delivery systems, implant surface coatings, and even environmental remediation. By synthesizing findings from recent studies, this comprehensive analysis underscores the transformative impact of metallic doping in optimizing HAp for diverse biomedical applications. These advances represent an important step in the development of multifunctional biomaterials, paving the way for innovative solutions to medical and environmental challenges.

Hydrosodalite-based geopolymers represent an environmentally sustainable class of materials. They are synthesised via the synergistic solid and liquid phase reactions between sodium hydroxide and uncalcined kaolin, resulting in the formation of a crystalline hydrosodalite phase that functions as a binder. This study examines the synthesis and characterisation of hydrosodalite-based geopolymers, which were produced at 150 °C for 2 h in a ventilated oven. In addition, the research investigates the feasibility of enhancing the performance of heat-cured hydrosodalite-based geopolymers by incorporating metakaolin and glass powder into the geopolymer system at weight ratios of up to 40%. XRD analysis indicated that after thermal treatment, the kaolin transformed into a structure containing both residual kaolin and a hydrosodalite phase. FTIR analysis confirmed significant structural changes in the kaolin due to thermal curing. These transformations led to enhanced mechanical strength and water resistance in the samples. Following the hydrosodalite transformation, new endothermic peaks and zeolitic water release that occurred at approximately 200 °C were observed in the samples using DTA-TG analysis. The incorporation of glass powder and metakaolin reduced water absorption and improved water resistance. However, incorporating glass powder did not result in a significant improvement in compressive strength and led to the development of microcracks within the microstructure. In contrast, the addition of metakaolin markedly enhanced compressive strength, even at lower dosages, with the highest compressive strength observed at a 30 wt% addition of metakaolin.

This study aimed to enhance the electric power generation of lead zirconate titanate piezoelectric (PZT) ceramics by optimizing stress distribution. Specifically, it focused on applying high stress over a broad area of the PZT ceramic to induce shape deformation in the PZT plate. Pre-straining the PZT plate into an arch shape improved voltage generation, reaching its peak at a maximum deflection of 0.04 mm due to the expanded and intensified stress distribution. However, exceeding this deflection threshold led to a decline in voltage output due to material degradation, including crack formation and 90° domain switching. Finite element analysis confirmed that the increased stress distribution in the pre-strained PZT plate contributed to higher voltage output. Additionally, electron backscatter diffraction analysis revealed that at higher pre-strains (deflection of 0.08 mm), 90°domain switching occurred, resulting in increased internal strain and potential crack formation. Experimental investigations using bulk PZT rods further demonstrated that moderate pre-straining effectively enhanced voltage output.

Metal-organic frameworks (MOFs), as the novel organic semiconductors, have attracted considerable attention for their properties and potential applications in environmental treatment. However, many studies have indicated that MIL-101(Fe)-NH₂ suffers from structural instability under the strong oxidative conditions of the photo-Fenton reaction. Herein, we firstly proposed a surface passivation strategy based on unstable MIL-101(Fe)-NH₂ in strong oxidation photo-Fenton reaction. In this study, SiO_xH@MIL-101(Fe)-NH₂ was synthesized by a simple in-situ reaction to obtain MIL-101(Fe)-NH₂ photocatalyst modified by an amorphous SiO_xH layer against photo-Fenton corrosion. The phase structure and surface chemical states of the SiO_xH@MIL-101(Fe)-NH₂ have been characterized, as well as its performance and promising application prospects in strong oxidation photo-Fenton reaction. From the comparison, bare MIL-101(Fe)-NH₂ photocatalyst has completed the photo-Fenton degradation under high-concentration H₂O₂ additive, meanwhile, it has been self-consumed in this strong oxidation reaction. However, SiO_xH@MIL-101(Fe)-NH₂ photocatalyst has performed the efficient catalytic activity no less than that of reference MIL-101(Fe)-NH₂ and with almost 100% retention after three cycles, while the latter declined to 50%. This work provides a novel approach to achieve low-cost, high-efficiency and highly corrosion-resistant MOF photocatalysts, paving the way for extended and enhanced water environmental treatment.

Piezoelectric ceramics are widely used in various fields owing to their excellent electromechanical conversion characteristics. Enhancing their piezoelectric constant (d₃₃) and Curie temperature (T_C) at elevated temperatures can improve its piezoelectric properties. In this study, (1-x)K_0.5Na_0.5(Nb_0.95Ta_0.05)O₃-x(Bi_0.5Yb_0.5)_0.95Ag_0.05ZrO₃ (KNNT-xBYAZ) piezoelectric ceramics were prepared by the traditional solid-phase sintering process. By regulating the doping amount of (Bi_0.5Yb_0.5)_0.95Ag_0.05ZrO₃(BYAZ), the ceramics were tailored to lie at the polymorphic phase boundary (PPB). Results from instrumental characterizations, including XRD, SEM, and EDS, revealed that BYAZ was fully incorporated into the KNNT lattice, forming a single perovskite structure. Specifically, when x = 0.0, the ceramic exhibited an orthorhombic phase; when 0.0 < x ≤ 0.03, it presented an orthorhombic-tetragonal phase; when 0.03 < x ≤ 0.05, it showed a rhombohedral-tetragonal phase. The performance test showed that the ceramics achieved optimal properties in the PPB region of x = 0.04 (d₃₃ = 323 pC/N, k_p = 43%, ε_r = 896, tanδ = 2.1%, P_r = 17.8 µC/cm², E_C = 20 kV/cm, and T_C = 355 ℃). This demonstrates that adjusting the phase transition temperature by varying the BYAZ doping amount is highly effective in enhancing the ceramic properties.

In the present work, the effects of barium calcium zirconium titanate (BCZT) on the properties of β-tricalcium phosphate (β-TCP) were investigated. The β-TCP and BCZT powders were synthesized by a solid-state reaction technique while β-TCP/BCZT ceramics were sintered at 1300 °C. Phase analysis by X-ray diffraction and Raman spectroscopy indicated that the samples consisted of many phases besides the main phase of β-TCP and BCZT. The BCZT additive produced an increase in density and a decrease in grain size, both of which were related to the enhancements of the mechanical properties of the β-TCP/BCZT samples. The samples also showed improved ferroelectric and piezoelectric properties. BCZT additive also increased the dielectric constant, but the samples’ loss tangent values remained low which was related to the density improvement. The simulated body fluid (SBF) test indicated that the β-TCP and 20 vol% BCZT samples exhibited the desired bioactivity. The results indicated that the samples showed substantial potential for future development and use in biomedical applications.

Dysprosium-doped cobalt ferrites with the composite formula CoFe₂₋_xDyₓO₄ were fabricated employing the solid-state synthesis method. This investigation thoroughly examines the effect of low levels of Dy doping on the structural and magnetic characteristics of cobalt ferrites. X-ray diffraction analysis verified that the compounds display a single-phase cubic spinel structure, with the lattice parameter increasing proportionally to the Dy dopant concentration. Scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), ultraviolet-diffuse reflectance spectroscopy (UV DRS), and magnetization measurements were utilized to investigate the microstructural, energy gap, and magnetic properties of these ferrite materials. The energy gap decreased from 1.47 eV to 1.43 eV. The introduction of Dy³⁺ ions into the cobalt ferrite matrix led to a shift in all vibrational modes towards lower frequencies, with the exception of the T_2g mode, which shifted to higher frequencies, indicating cation redistribution within the spinel structure. The Dy-doped samples demonstrated a decrease in saturation magnetization compared to the undoped cobalt ferrites. A comprehensive examination was undertaken to analyze the changes in magnetic and dielectric characteristics with varying Dy doping concentrations.

In this study, hydroxyapatite (HA) was synthesised using a controlled precipitation method, with the solution’s pH adjusted to 11 to ensure optimal precipitation. The obtained material was dried and calcined at 600 °C, forming a crystalline HA structure. The success of the synthesis process was confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses, which revealed characteristic functional groups and crystalline phases of high-purity HA. To enhance its mechanical properties for biomedical applications, silica was incorporated into the HA matrix at varying concentrations. Among the tested compositions, the sample containing 2.5 wt% silica sintered at 1200 °C exhibited superior performance, with a compressive strength of 103 MPa, Young’s modulus of 2829 MPa, and Vickers hardness of 372.8 HV. By comparison, pure HA achieved only 24.3 MPa, 1343 MPa, and 263.4 HV, respectively. This optimal composition and processing condition demonstrate that silica reinforcement significantly enhances the strength, stiffness, and hardness of HA, making the composite promising for biomedical applications such as bone tissue engineering and implant coatings.

Traditional ceramic materials rely on high-purity alumina and synthetic silica, which are energy-intensive and costly, resulting in an increasing global demand for lightweight and energy-efficient alternatives. Agricultural residues serve as eco-friendly reinforcement materials in the synthesis of ceramic composites for diverse industrial applications. However, the combined effect of processing parameters such as particle size, reinforcement volume, and curing temperature on the integrity of the composites is understudied. Kaolin-based ceramic composites reinforced with rice husk ash (RHA) were synthesised using a stir casting method. Six levels (L) of the ceramic composites were produced based on the volume composition of the reinforcement: 2.5, 5, 7.5, 10, 12.5, and 15 wt% % RHA. Three major processing factors were considered: Curing Temperature (CP), Particle Size (PS), and Volume of Reinforcement (VR). The particle sizes were 30 μm, 45 μm, and 60 μm, while the curing temperatures were 28 °C, 100 °C, and 130 °C. The optimisation of process parameters was conducted using the Taguchi method L18 orthogonal array. The signal-noise (S/N) ratio was used to determine the optimum process parameters. The experimental results showed that reinforcement (VR) at 10% followed by the particle size (PS) at 45 μm, were the key performance parameters, while the curing temperature (CT) 100 °C had the least impact. A similar analysis was also obtained using the Taguchi method, showing that both the experimental and theoretical studies were in agreement. Notably, 10wt% reinforcement produced superior tensile, impact, and flexural strength properties.

With increasing global water scarcity, there is an increasing need for developing low-cost efficient natural adsorbents for water purification. The discharge of methylene blue (MB) organic dye from wastewaters is a significant issue due to its huge waste production and hazardous impacts on environment and health. In this study, the primary mineral found in bone and tooth tissues, Hydroxyapatite (HA)-based nanoceramics were investigated for MB adsorption potential. Having exhibits exceptional mechanical strength, chemical resistance, hydrophilicity as well as its biocompatibility and bioactivity, HA has high stability and notably eco-friendly when benchmarked against alternative adsorbents, such as activated carbon. To improve adsorption potential of HA, it was enriched with natural zeolite, clinoptilolite (CLP) with integrated mesoporous structure. HA-CLP nanoceramics were synthesized by sol-gel method, and their dried and sintered forms were investigated for MB removal efficiencies. With initial experiments, the most efficient two compositions were chosen as dried HA-CLP and its sintered form at 800 ℃ having porous interconnected morphologies. The influence of pH(2–12), adsorbent concentration (0.1–1.5 g/L), dye concentration(5–25 mg/L), and contact time(2–120 min) were examined, and kinetic studies were executed with the chosen compositions. MB adsorption on nanoceramics was confirmed elementally by Energy Dispersive X-Ray (EDX) analyses. The optimal pH for both compositions was determined as pH 7. MB removal efficiency has constantly improved reaching a saturation after 90 min, and the maximum removal efficiency after 120 min with HA-CLP adsorbent was reached to 90.3 ± 0.8%. Therefore, HA-CLP nanoceramics can be potential adsorbent materials for the removal of MB for wastewater treatments.