Journal of the Australian Ceramic Society最新文献

This study investigates the tribological and mechanical properties of aluminium matrix composites (AMCs) reinforced with copper chromate (Cu₂Cr₂O₅) nanoparticles, presenting a novel approach to utilizing Cu₂Cr₂O₅ as a reinforcing phase in AA6018 composites fabricated via plasma arc processing. This is the first comprehensive work demonstrating the formation of a nanoscale eutectic structure that significantly enhances tribological performance by refining the microstructure and facilitating a stable lubricating film, thereby reducing wear and friction. The composites were developed with Cu₂Cr₂O₅ weight percentages ranging from 1 to 3 wt%. The results indicated that 2.5 wt% reinforcement achieved optimal performance, offering the lowest wear rate and friction coefficient due to forming a solid lubricating film. The hardness of the composites increased by 41.3%, with a peak value of 520 HV for 3 wt%, while excessive reinforcement led to particle detachment and reduced effectiveness under high loads. These findings underline the potential of Cu₂Cr₂O₅-reinforced AMCs for advanced aerospace and automotive applications, offering superior wear resistance and mechanical strength.

This study investigates the physical and mechanical properties of alkali-activated mortars, in which thermal power plant fly ash (FA) was partially replaced by cupola furnace iron slag (IS). An optimal mix design determined through preliminary tests consisted of an aggregate-to-binder ratio of 1.5 (by weight), NaOH solution concentration of 10 M, Na₂SiO₃ (liquid) to NaOH (solid) ratio of 2, and a water-to-binder ratio of 0.3, all maintained consistently across mixtures. Chemical compositions and phase structures of raw materials were characterized using X-ray fluorescence (XRF) and X-ray diffraction (XRD), respectively. Particle size distribution was determined by laser diffraction analysis, and microstructural morphology was examined using scanning electron microscopy (SEM). Bulk density and apparent porosity were measured using Archimedes’ method with water as the immersion medium. Mechanical properties were evaluated through compressive strength and three-point bending tests after 28 days of curing. Results showed that mortars incorporating 75 wt% cupola furnace iron slag as a fly ash replacement exhibited superior performance, achieving a bulk density of 2118 kg/m³, apparent porosity of 12.2%, compressive strength of 44 MPa, and flexural strength of 10.2 MPa. These findings highlight the potential of iron slag as an effective supplementary material in alkali-activated mortars, enhancing mechanical properties and contributing to microstructural densification.

The corrosion mechanism of municipal solid waste incineration (MSWI) fly ash on magnesia-chromium refractories from the perspective of substance migration and transformation was investigated by using corrosion test at 1400 ℃. XRD, XRF, and SEM-EBSD characterization and thermodynamic software FactSage analysis were utilized. Although thermally stable compound MgCr₂O₄ can be formed in the refractories mitigating the corrosion, the SiO₂ in the fly ash can convert MgCr₂O₄ to Mg₂SiO₄ (forsterite) and MgSiO₃.The regeneration and transformation of MgCr₂O₄, as well as the low melting point and volume expansion properties of Mg₂SiO₄ and MgSiO₃, are responsible for the loosening of the refractory structure and the migration of magnesium from the refractory into the ash. When the refractory was corroded by MSWI fly ash repeatedly, the migration of the corrosion products from the refractory to the ash was the key to aggravate the corrosion. Increasing CaO content can mitigate the corrosion and magnesium migration by alleviating the formation of Mg₂SiO₄ and MgSiO₃.

The biological and mechanical characteristics of a material used in biomedical applications depend on its chemical composition, while its surface properties are significantly influenced by the synthesis route. This study investigates the impact of chemical structure and surface properties on the bioactivity and mechanical stability of tertiary silicate bioceramics (akermanite and merwinite). Citric acid, used as a fuel in combination with the sol–gel combustion method, effectively reduced the synthesis time and temperature for these bioceramics. The formation of akermanite and merwinite phases was confirmed through X-ray diffraction (XRD) analysis, while microscopic analysis revealed a porous surface morphology. Among the two bioceramics, akermanite exhibited superior mechanical strength, whereas merwinite demonstrated lower mechanical values than human cortical bone. However, merwinite displayed a considerably higher apatite-forming ability than akermanite, achieving complete surface coverage within seven days of immersion in simulated body fluid (SBF). Furthermore, the study highlights that the bioactivity and mechanical strength of these silicate ceramics are closely linked to their dissolution and degradation behavior.

This study provides theoretical support for the design of high-performance ceramic materials by predicting material properties at the microscopic level and establishing macroscopic and microscopic linkages to solve the blindness of the traditional design methods for ceramic materials. Voronoi diagram with stochastic method was used to construct a parametric model of microstructure of ceramic materials, and the optimal structural parameters were determined through performance tests and simulations: 70%, 10%, and 20% volume fractions of Al2O3, WC, and TiB2, respectively. Based on the linear elasticity and cohesion model, the loaded deformation and crack extension of the material were simulated, revealing the influence of microstructure on the mechanical properties. Ceramic materials were prepared using SPS sintering technology, and the experimental and predicted results were consistent, verifying the validity of the performance prediction. The optimization theories and methods proposed in this study are very important to improve the mechanical properties of ceramic materials.

This study involves the synthesis of zinc oxide nanoparticles (ZnO-NPs) and their incorporation into polymethyl methacrylate (PMMA) to produce PMMA/ZnO-NPs nanocomposites. The nanocomposites are prepared using the solution casting method, with ZnO-NPs mass contents varying between 1% and 7%. X-ray diffraction (XRD) analysis revealed a hexagonal wurtzite structure for ZnO–NPs, which formed a phase-separated structures with the PMMA matrix. Scanning electron microscopy (SEM) images showed that ZnO-NPS were homogeneously distributed throughout the PMMA polymer matrix and higher ZnO-NPs content led to increased particle size and agglomeration. Fourier transform infrared (FTIR) confirmed ZnO integration. UV-Vis spectra indicated that ZnO-NPs influenced the optical properties of PMMA, with ZnO-NPs/PMMA 3% composite showing the highest absorption and good nanoparticle dispersion. Thermogravimetric analysis (TGA) indicated enhanced thermal stability, with composites showing a 12 °C higher degradation temperature than pure PMMA. Photocatalytic performance was evaluated by degrading an azo dye (Acid Red) under UV light. Both ZnO–NPs and PMMA/ZnO-NPs composites achieved up to 99% dye removal at 10 mg/L within 2 h. According to the kinetic study, the photodegradation process followed pseudo-second-order model. Optimal dosages were 2.8 g/L for ZnO–NPs and 2 g/L for PMMA/ZnO-NPs composites. PMMA/ZnO-NPs composites demonstrated moderate recyclability over four cycles, making them suitable for sustainable water purification applications. This work highlights the potential of ZnO–NPs/PMMA as cost-effective, thermally stable, and efficient photocatalysts for environmental remediation.

The development of piezoelectric nanogenerators (PENGs) using Zn doped barium titanate (Zn-BaTiO₃) within polyvinylidene fluoride (PVDF) matrices has shown significant potential for energy harvesting applications. This study was focused on the synthesis of Zn-BaTiO₃ through sol–gel route and fabrication of Zn-BaTiO₃/PVDF nanocomposites via., solvent casting techniques. The effects of various doping levels were investigated through XRD, FT-IR, FESEM techniques based on their shape and morphology of Zn-BaTiO₃ and Zn-BaTiO₃/PVDF nanocomposites. Raman spectroscopy and Photoluminescence spectra were used to confirm the doping of Zn and defect states present in the Zn-BaTiO₃. The fabricated nanocomposites were also successfully characterized using TGA and DSC to confirm the thermal stability and phase transformation. The presence of defect states was confirmed by decreased emission intensities at 420 to 480 nm, which corresponds to the defect-mediated transitions. The influence of Zn-BaTiO₃ in PVDF matrix was proved by the improvement of dielectric permittivity and piezoelectric response of the fabricated nanocomposites. The PVDF with 2wt% of Zn-BaTiO₃ is shows an enhanced output voltage of 1472 mV which is 1.56 times higher than pure PVDF and it would be a promising candidate for advanced piezoelectric nanogenerators, capable of efficiently converting mechanical energy into electrical energy for powering low power electronic devices.

With the continuous rise in construction and demolition waste (CDW) generation and the increasing demand for sustainable construction materials, this study aims to explore the potential of utilizing recycled concrete aggregate (RCA)—the most abundant component of CDW—as a replacement for natural aggregate (NA). Mortar samples incorporating untreated recycled fine aggregate (RFA), natural fine aggregate (NFA), and carbonated RFA (CRFA) were produced to determine whether the mechanical and durability drawbacks of RFA can be mitigated through accelerated carbonation. In this context, the workability, mechanical strength, water absorption capacity, capillary water absorption behavior, freeze–thaw and chloride permeability properties of the mortars were analyzed. The results indicate that the negative impact of RFA on engineering properties can be significantly reduced through accelerated carbonation. Despite all aggregates being in a saturated surface dry state, RFA exhibited the lowest flowability, while NFA had the highest. In strength tests, CRFA-containing mortars achieved performance levels comparable to those with NA. However, RFA mixtures demonstrated considerably higher water absorption and permeability than NA, while CRFA improved these properties. Additionally, RFA mortars experienced greater weight loss during freeze–thaw cycles, but carbonation treatment helped mitigate this deterioration. These findings highlight the potential of accelerated carbonation treatment as an effective method for upgrading RCAs, contributing to more sustainable construction practices.

Multi-scale retinal enhancement and weighted homomorphic filtering algorithms are proposed to address the problems of weak texture features, unclear detail information, and uneven and low contrast of feature regions in Si₃N₄ bearing roller images. Combined with the weak texture characteristics of Si₃N₄-bearing roller microcracks, this creates the multi-channel convolution equation for retinal color recovery. Break down the characteristics of an image into information across various scales and boost the contrast of the texture's less prominent features. Based on the different gray value components of different frequencies of the feature image, distinct gray value components exist according to the feature image's various frequencies. Set up the Gaussian difference equation, extend local grayscale values, and realize noise removal of texture features`. The average PSNR of the optimized microcrack weak texture feature image is 21.4556 dB, as per the results. By comparing the experiments, the image entropy is improved by 23.8% on average, which effectively enhances the roller microcrack contrast and details of the texture feature image, improves the accuracy and quality of feature images.

To address the problems such as background noise and uneven illumination during the extraction of ancient ceramic patterns. A nondestructive extraction method for missing patterns in ancient ceramics is proposed. Combined with the characteristics of the pattern, the median filter matrix equation is designed to denoise the image. By defining the median filter equation function for the high-frequency approximation coefficient of the wavelet transform, the details of the ancient ceramic pattern are clearer. The double histogram equalization algorithm is built to maintain the average brightness of the image, which is helpful to the extraction and analysis. The verification shows that the method can effectively eliminate the interference of noise on the extraction of the ancient ceramic pattern, and the accuracy of the segmentation reaches 94%. It effectively promotes the restoration and protection of ancient ceramic cultural relics.