Journal of the Australian Ceramic Society最新文献

Calcite is one of the significant components used in the wall tile application at a rate of 10–12% as its content contributes to the formation of pores. This study investigates the usability of snail shell waste with high calcium oxide content as an alternative to calcite raw material. Thus, depletion of calcite reserves will be prevented and value-added commercial products will be obtained by using waste. In addition, proper waste management will prevent environmental pollution and damage caused by waste accumulation. The chemical analysis of snail shell waste revealed a CaO content of 55%, while the CaO content in calcite was measured at 58%. Considering their similar chemical properties, different amounts of snail shell waste (%6, %9, %12) were added to the wall tile recipe instead of calcite. The addition of snail shell waste to the recipe resulted in an increase in sludge density and viscosity. Physical and mechanical tests were conducted on wall tiles made with the addition of snail shell waste and compared to standard wall tiles according to TSE EN ISO standards. When the waste material was used in a 50–50 ratio with calcite, the strength of the recipe was calculated to be 279.41 kg/cm². Water absorption values were within standard limits and recorded at 15%. The phases that occur in the structure of wall tiles with the increase of waste addition were examined by X-ray Diffraction Analysis. The microstructures of the samples were compared with SEM–EDX analysis. Sustainable and low-cost wall tiles were obtained through the use of snail shell waste, with environmentally friendly solutions.

Mesoporous calcium phosphate based-bioceramics with ionic substitution have attracted attention for treatment of bone diseases and bone regeneration. Carbonate apatite (CO₃Ap) is a promising candidate for bone replacement through bone remodelling, similar to that of autologous bone, owing to the chemical composition of the bone mineral. In this work, we present a dual approach to synthesize mesoporous carbonate apatite (CO₃Ap) and strontium-substituted CO₃Ap (Sr-CO₃Ap) artificial bone nanocrystals, aiming to assess the impact of strontium on CO₃Ap characteristics and biological performance. Mesoporous CO₃Ap was created by transforming hard templates composed of CaCO₃, while Sr-substituted CaCO₃ (Sr-CaCO₃) microspheres were formed using an organic complexing agent to induce pore formation. The resulting CO₃Ap and Sr-CO₃Ap granules exhibited an irregular shape, with rod-like nanocrystals composing their particles. Adsorption/desorption isotherms confirmed the mesoporous nature of the structures, featuring pore sizes ranging from 10 to 50 nm. Specifically, mesoporous CO₃Ap displayed slit-like pores, while Sr-CO₃Ap showed cylinder-like ones. High-resolution transmission electron microscopy images of Sr-CO₃Ap powder revealed mesopores within the particles, with Sr-CO₃Ap exhibiting larger pore volume and specific surface area compared to CO₃Ap. When osteoblast-like MC3T3-E1 cells were cultured on both CO₃Ap and Sr-CO₃Ap samples, they demonstrated good cell attachment, proliferation rates, and increased ALP activity, particularly evident at higher strontium concentrations. These findings suggest promising potential for further exploration of mesoporous apatite nanocrystals in bone replacement and drug delivery applications.

This study investigates the mechanical and wear properties of AA6061 composites reinforced with monosynthesized Al₂TiO₅ particles. Bottom pouring and stir casting were employed to achieve uniform dispersion of Al₂TiO₅. Five composite samples were fabricated with varying Al₂TiO₅ weight percentages (wt%) (0, 1, 2, 3, and 3.5) while maintaining a constant stirring speed of 400 rpm. Tensile strength, impact energy, and microhardness were evaluated according to ASTM standards. Wear rate and coefficient of friction (CoF) were measured using a Pin-on-Disc apparatus on samples prepared through ASTM G99. Composites reinforced with 2 wt% and 3.5 wt% Al₂TiO₅ exhibited the highest tensile strength (215.96 MPa) and impact strength (12.6 J), respectively. Microhardness increased significantly in samples 6R1 (75.37 HV), 6R2 (83.75 HV), and 6R3 (91.6 HV) compared to 6R0 (71.52 HV) and 6R3.5 (72.26 HV). Based on the finding that 1, 2, and 3 wt% Al₂TiO₅ reinforcement improved hardness, RSM optimization was applied to these compositions to further adapt the wear rate and CoF. Field emission scanning electron microscopy (FESEM) was used to examine the worn surface morphology of the composites and understand how Al₂TiO₅ particles influence wear mechanisms. The 3 wt% Al₂TiO₅ reinforced composite demonstrated an 83.5% increase in wear resistance compared to other samples under a 10 N load and 1600 m sliding distance.

This study focuses on how the chemical makeup of the glass' basic components affects the glass' structure and optical characteristics. Four glass samples have been created for this purpose using the chemical formula; 94 mol% Na₂B₄O₇—(6-x) mol% CeO₂ – x mol% Ce(NO₃)₃, where 0 ≤ x ≤ 6. The Ce cations in this formula have two separate chemical sources, CeO₂ and Ce(NO₃)₃, with CeO₂ eventually being replaced by Ce(NO₃)₃. The standard melt-quenching technique was used to prepare the studied glasses. While X-ray direction (XRD), differential scanning calorimetry (DSC), and UV–vis were used for the structural and optical characterizations. XRD patterns revealed the short-range order glass networks for the prepared samples, while DSC thermograms showed that when CeO₂ was replaced with Ce(NO₃)₃, the glass transition temperature (T_g) decreased, causing the glass stability to improve. The optical characterization resulted in the finding that when CeO₂ was replaced with Ce(NO₃)₃, the Urbach's energy increased with a decrease in bandgap energies, which reflects an increase in the glass homogeneity. Finally, the results may imply that Ce(NO₃)₃-based glasses can be proposed for usage in applications for UV blockers, radiation shielding, light attenuation, and n-type semiconductors.

Nowadays, bioglasses have been introduced universally. However, controlling the physical and biological properties of bioglass is complicated. Hence, tailoring their composition and heat-treatment procedures could be beneficial. In the present study, the fluorapatite-containing bioglass-ceramic powders were synthesized via a sol-gel route in two systems, 50SiO₂-39CaO-11P₂O₅ and 64SiO₂-28CaO-8P₂O₅. Furthermore, it is aimed to examine how additives affect the final microstructure by the addition of TiO₂ and ZnO to the chemical formula. Also, another effective parameter that was investigated is the heat-treatment temperature. Based on the XRD and FESEM results, the spherulitic morphology of fluorapatite-containing phases in additive-containing samples proved that the presence of TiO₂ oxide was more influential than ZnO oxide in controlling the crystallization and growth of the desired phases. FTIR results confirmed that increasing the heat-treatment temperature from 700 ℃ to 1100 ℃ caused more intense Si-O and P-O functional groups. There was also no cytotoxicity effect in all samples based on the MTT assay results. Based on the mechanical investigation, the presence of ZnO oxide increased the flexural strength of sintered samples up to 60 MPa.

This study investigates the influence of various anodic oxidation parameters on the photocatalytic activities of the nanostructured titanium dioxide (TiO₂) films. TiO₂ films were prepared by anodic oxidation of titanium substrate using 1 M Na₂SO₄ / 5 wt. % NH₄F electrolyte, and then annealed at 500 °C. Anatase appears in all calcined samples. The anodic oxidation process was performed in two steps at different voltages (5–80 V) and times (15–480 min) to reveal the relationship between the surface morphologies, wettability and photocatalytic properties. The results showed that the voltage and anodization time can play important role in the surface morphology of nanostructured TiO₂ films and thus in various properties. While 40 V showed the most efficient photocatalytic degradation among voltage values, 60 min was the most efficient time for photocatalytic degradation efficiency and lowest contact angle. In addition, a pore area fraction of 39.54%, equal diameter of 96.81 nm, and circularity of 66.7% were obtained from image analysis of the 60-min anodized sample. While increasing the voltage and time benefited up to a point in terms of photocatalytic efficiency, changes in morphology had a negative effect after a point. At low voltage and time values, small pore diameters result in low photocatalytic properties. This titania can be readily utilize to meet application expectations in areas such as gas sensors, photocatalysis and photovoltaic cells.

BaBiLaNbVO₉ is a lead-free compound and has been synthesized by solid-state technique. The formation of the compound was confirmed by X-ray diffraction and is found to be crystallized in the monoclinic (space group P 2₁) crystal system (a = 13.7464± 0.0015 Å, b = 4.0156± 0.0012 Å, c = 12.4946 ± 0.0018 Å, β = 93.48 ± 0.01^o). The crystallite size was found to be 52.91 nm. SEM and EDX studies analyzed the morphology, composition, and elemental distribution in the specimen. The average grain size is about 1.0651 μm. Several properties, such as frequency and temperature response resistivity, conductivity, and dielectric behaviours of the compound, have been analyzed. The overlapping large polaron tunnelling (OLPT) and correlated barrier hopping (CBH) models are appropriate for electrical conduction in the compound. The energy band gap (E_g) of the material was 2.40 eV, suitable for optoelectronic devices. Ferroelectric behaviour may be deduced from symmetric and well-shaped P-E hysteresis loops. The impedance study satisfies the negative temperature coefficient of resistance (NTCR) behaviour, which is suitable for thermistor devices and its correlated application.