Journal of the Australian Ceramic Society最新文献

In the present study, for the first time the machine learning (ML) based refractive index (n) approach is established depends on the density (ρ) parameter of glasses for a dataset of 2000 oxide glasses to predict refractive index of B₂O₃-CaO-Li₂O-Sb₂O₃ glasses. Density of the investigated glasses varied from 2.56 to 2.97 gm/cm³. The corresponding refractive index was changed from 2.540 to 2.405. The refractive index prediction based on density parameter derived from the density of glasses and constant ‘K’. For all M-L techniques including gradient descent (GD), artificial neural network (ANN), and random forest regression (RFR), the density factor is used as an independent variable and the experimental refractive index as a dependent variable. The data set of 10,000 oxide glass samples was employed to forecast density using a variety of machine learning approaches. In comparison to other models, the Random forest regression (RFR) model fitted the glass data with the highest R² value of 0.949 for refractive index prediction and 0.925 for density prediction. For both the prediction of density and refractive index, the R² is controlled to 0.932 and 0.9223, respectively. The highest R² values for refractive index and density prediction were gained when the tanh activation function was used in an artificial neural network (ANN) with varied activation functions.

The need for biomass materials that are both cost-effective and highly effective has increased rapidly in a number of areas, including flexible electronics. The aim of this research is to investigate the properties of a screen-printed thick film of Prosopis Africana charcoal (PAC) on an alumina substrate. The biochar was obtained from the Prosopis Africana strain by subjecting it to controlled pyrolysis at 500 °C for 3 h. The rheological properties of the PAC pastes were formulated at a powder-to-organic binder ratio of 40:60 wt%. An average 11.8-µm-thick layer was produced using the screen-printing process. X-ray diffraction analysis showed the presence of characteristic peaks at approximately 25.0° and 44.7°. These peaks correspond to the (002) and (004) reflections of the graphite structure. Thermogravimetric analysis revealed that the PAC film exhibited thermal stability in an airflow environment up to 650 °C. The surface morphology of the PAC thick film exhibits a reticulated appearance with patchy features, while elemental composition analysis (EDX) confirmed the high carbon content of the PAC thick film. The real and imaginary dielectric constants of the PAC thick film at 10 GHz were found to be 9.8 and 1.8, respectively. It can be concluded that the PAC biochar has promising electronic properties, making it a suitable candidate as an environmentally friendly material for a range of electronic applications.

Hydroxyapatite (HA)-based nanocomposite coatings on 316L stainless steel (SS316L) implants can be modified by components such as chitosan/gelatine (CS/Gel) and reduced and functionalized graphene oxide (rfGO) to improve antibacterial properties and biocompatibility. In this research, HA and rfGO were produced. HA-CS/Gel-rfGO nanocomposites with different HA values (200, 500, 800, and 1100 mg) were applied by electrophoretic deposition (EPD) at various voltages (80, 100, and 120 V). Analyzing HA and rfGO by XRD, SEM, and FTIR proved the successful synthesis. The contribution of HA and coating voltage was investigated on the morphology, microstructure, and corrosion behavior by morphological studies, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization. The possible intermolecular interactions between coating components were evaluated and found to be effective on the coating performance. Increasing HA reduced the cracks but caused unfavorable agglomerations and uneven distribution of the constituents in the coatings. Higher voltages caused voids and porosities. The coating at 1100-mg HA was porous but crack-free. The coating thickness increased by voltage and HA, from ~ 9.3 to 14.8 µm. Electrochemical polarization and EIS analysis in SBF solution showed that corrosion behavior is affected by coating morphology and bonding configurations among HA-CS/Gel-rfGO. The lowest corrosion rate occurred in the lowest HA (200 mg), with a corrosion resistance of 143,000 Ω.cm². At constant HA, increasing the applied voltage significantly decreased the corrosion resistance from 23,046 to 15,000 Ω.cm², and an induction bend occurred at 120 V. The corrosion mechanism was carefully investigated by an equivalent circuit with two time constants and corresponding dielectric capacitors.

This study focuses on how titanium oxide (TiO₂) in concentrations ranging from 0.5 to 4% by weight added the hydroxyapatite (CHA) made from chicken femur bones’, affects sinterability, microstructural, mechanical, and in vitro bioactivity properties. According to the results of the experiments, it was determined that CHA decomposed into whitlockite, alpha tricalcium phosphate (α-TCP), tetracalcium phosphate (TTCP), and calcium oxide (CaO) phases at different temperatures. Rutile and perovskite (CaTiO₃) phases were also found in TiO₂ added CHAs in addition to these phases. With increasing sintering temperature of CHA, the diameters and the heights of the samples decreased. Density increased up to 1250 °C and decreased at 1300 °C respectively. while the partial density value showed similar behavior with density and hardness, At 1200 °C, the maximum values of fracture toughness (1.071 MPam^1/2) and compressive strength (145.417 MPa) were attained; however, as sintering temperatures increased, these values shifted downward to 0.882 MPam^1/2 and 111.096 MPa, respectively. It has been determined that grain growth and decomposition are the underlying factors in obtaining the highest density, hardness, fracture toughness and compressive strength values for CHA at different temperatures. Among the TiO₂ added CHAs, the best properties are obtained for CHA-0.5TiO₂ sintered at 1300 °C (Density: 3.0057 g/cm3, Hardness: 3.973 GPa, Fracture toughness: 1.583 MPam^1/2 and Compressive strength: 170.045 MPa) and the properties of the CHA-TiO₂ composite decreased with increasing TiO₂ ratio. This is due to the fact that increasing TiO₂ has a detrimental impact on CHA’s sinterability behavior and causes it to become more porous and degrade more quickly. It was discovered through in vitro bioactivity and cell culture assays that the addition of TiO₂ had a detrimental impact on the proliferation of bone tissues.

Halloysite nanotubes a naturally occurring type of clay with unique properties. This research intends to investigate of the effects of hydrochloric acid treatment on the physicochemical and pore properties of halloysite nanotubes. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, the nitrogen adsorption-desorption isotherm (BET), thermogravimetric analyses (TGA-DTA) and X-ray photoelectron spectroscopy (XPS) were used to analyze the structure of natural, calcined, and acid-treated calcined halloysite nanotubes. From the analysis of XRD, SEM, FT-IR, BET, and TGA-DTA, it was possible to infer that activation with HCl on the calcined nanotubes allowed for an increase in the specific surface area and the volume of pores while maintaining the tubular structure of these materials. Because the samples’ tubular structure was preserved, the study’s goal was to evaluate the effects of acid treatment on calcined halloysite nanotubes for use as potential adsorbents. The influence of treatment with hydrochloric acid on the structure of halloysite nanotubes calcinated at different temperatures was investigated using a surface sensitive XPS method.

The wear-resistant cermet coating of WC-Cr₃C₂-Ni was deposited via high-velocity air–fuel spraying on the beryllium bronze substrate. The wear characteristics of the coatings were investigated under different types and parameters of wear while comparing the effects of various factors on measurement accuracy and visibility. The friction coefficient of the WC-Cr₃C₂-Ni coating exhibited a lower value in the reciprocating wear experiment compared to that observed in the sliding wear experiment. The mass loss and friction coefficient of the coating increased with the rise in sliding speed and normal load in sliding wear. The wear of the coating is primarily attributed to adhesive wear, with a relatively lower proportion observed in reciprocating wear compared to sliding wear. The proportion of adhesive wear decreased with increasing speed, while it increased with increasing normal load. Moreover, the sensitivity of adhesive wear to normal load surpassed that of sliding speed. The experimental results showed that the tribological properties of WC-Cr₃C₂-Ni coating can be well demonstrated by both the reciprocating wear test and sliding wear test when the wear parameters of low load and high speed were used. This study will offer theoretical backing for the selection and assessment of polyphase hard coating materials across diverse industries. high-velocity air–fuel (HVAF).

The poor thermal shock resistance of bone china body still limits its market value to a large extent. Here a novel prestress way is reported to improve the flexural strength and thermal shock resistance by constructing the sandwich structure bone china body, which consists of bone china matrix (intermediate layer) and prestressed coatings (upper and lower surface layers). The key to this strategy is to optimize the mismatch in coefficient of thermal expansion between the coating and the matrix to maximize the prestress. The bone china with the prestress strategy exhibits a flexural strength of 154 ± 5 MPa, representing an increase of 45% compared to pristine bone china body (108 ± 3 MPa). As a result, the thermal shock resistance of as-prepared the bone china body is enhanced from 140℃ to 180℃, meeting the standard of traditional feldspar porcelain. It is believed that the simple and cost-effective prestress design holds great potential for improving the flexural strength and thermal shock resistance of bone china.

This study investigated the optimization of the electrical discharge machining (EDM) process for TiN-Si₃N₄ composites, a challenging and emerging field in materials engineering. To achieve superior machining efficiency and product quality, a hybrid computational intelligence algorithm, Grey-ANFIS (adaptive neuro-fuzzy inference system), was employed. First, comprehensive data on EDM process parameters and performance characteristics were collected. Then, Grey-ANFIS was used to model the complex relationships between the EDM process parameters (e.g., pulse on time, pulse off time, voltage, and current) and key performance indicators (e.g., material removal rate and electrode wear rate). The algorithm combined the adaptability of neural networks with the linguistic representation capabilities of fuzzy logic, making it well-suited for capturing the intricate, non-linear EDM process dynamics. The proposed approach enables the generation of precise predictive models that can accurately represent EDM process behavior. Subsequently, these models were employed to optimize EDM process parameters, thereby enhancing machining efficiency and product quality. A sensitivity analysis was also conducted herein to identify critical factors affecting the EDM process. The results demonstrated the efficacy of the Grey-ANFIS algorithm in achieving superior EDM process optimization for TiN-Si₃N₄ composites.

Group-II aluminates have a spinel structure widely used for energy storage purposes due to high thermal, chemical, and dielectric properties. These applications can be enhanced by the substitution of a small content of magnetic transition metals. In this study, M_xSr_1-xAl₂O₄ (where M = Mn, Fe, and Co and x = 0.1) compositions were successfully synthesized via a well-known hydrothermal technique. The uniform nano-sized sheets with the monoclinic structure without any impurity phase were confirmed by X-ray diffraction and field emission electron microscopy analysis. The qualitative and quantitative analysis studies reveal the presence of expected elements with their respective wt.% ratio observed through energy dispersive spectroscopy analysis. A clear non-magnetic and paramagnetic behavior with high saturation and remnant magnetization was observed from the M-H loop at room temperature for pure and transition metal (Mn, Fe, and Co) substituted Sr-aluminate samples. The highest values M_s, M_r, and H_c, i.e., 0.020 emu·g⁻¹, 0.005 emu·g⁻¹, and 0.026Oe are recorded for Co-doped SrAl₂O₄ composition. The dielectric studies reveal an increase in the value of the dielectric constant and a decrease in energy loss factor from 0.27 to 0.18 confirming the stability of the structure, and enhancement in ferroelectric parameters making these suitable candidates for energy storage applications.