Journal of the Australian Ceramic Society最新文献

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.

By tailoring and optimizing the structure of core or shell material, complete alteration of properties of the material can be obtained. Herein, we have reported synthesis of CaCu₃Ti₄O₁₂@CoFe₂O₄ particles through the chemical co-precipitation route. CaCu₃Ti₄O₁₂@CoFe₂O₄ particles consist of CaCu₃Ti₄O₁₂ (~ 200 nm) as a core and CoFe₂O₄ as a shell of 2.5 nm. The prepared composites are characterized with appropriate characterization tools. The morphological results confirm the proper formation of core shell structure where CaCu₃Ti₄O₁₂ and CoFe₂O₄ act as a core and shell, respectively. The greater CCTO content composites exhibited promising relative permittivity of 8.2 × 10³ at 700 °C sintering temperature (8 h) at frequency 40 to 8 MHz. When CaCu₃Ti₄O₁₂@CoFe₂O₄ undergoes heat treatment, it leads to the removal of oxalic acid. However, a weight loss of 8.3% is obtained for CCTO-coated composites that is quite low as compared to ~ 11% weight loss obtained in pristine CFO. The removal of organic groups significantly contributed to the increase in dielectric properties. These results imply that the development of CaCu₃Ti₄O₁₂@CoFe₂O₄ core shell structure paves the wave for high-performance devices.

Exploring ways to modify electrode surfaces is key to protecting the electrode while improving the performance of dye-sensitized solar cells (DSC). This study investigated the effect of surface modification with the amino quinonoid 4-methylamino-6-methylamino-3-oxocyclohexa-1,4-dien-1-olate (AQZ) of Pt counter electrode, the most effective and widely-used DSC cathode, on the photovoltaic performance of DSC. The Pt surface on conductive glass substrates was treated with AQZ solutions at various concentrations (0.2–2.0 mg.mL⁻¹) and intervals (0.5–60 min) and characterized by X-ray photoelectron spectroscopy and field emission scanning electron microscopy to examine the chemical environment and morphology, respectively. The I⁻/I₃⁻ reactions with bare and AQZ-treated electrodes were compared using cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarized measurement. Current–voltage analysis showed that Pt cathode treated with 2 mg.mL⁻¹ AQZ for less than 5 min or in diluted AQZ solution (0.2 mg.mL⁻¹) for as long as 60 min could improve the photovoltaic performance of DSC as much as 22%, mostly due to the enhancement of the short circuit current (about 3–4 mA.cm⁻²). The promising results of electrode surface modification with AQZ developed in this report allow future development of simple methods to further improve photovoltaic devices as well as for a wide range of applications in metal surface protection.

The purpose of this in vitro study was to assess the color stability of esthetic restorative materials after immersion in different pediatric drugs. Three different restorative materials namely composite resin, alkasite and high-viscosity glass ionomer cement(HVGIC) were used to prepare total 96 (32 from each) disc-shaped specimens(2mmx5mm). A spectrophotometer was used to record the color of each sample after sample preparation and 7 days following the staining technique. After 1-week period, ΔE ∗ values were calculated. The average color changes(ΔE) for all drugs/restorative materials ranged from 1.81 to 8.08. The most prominent alteration was found in Cough syrup-Alkasite(8.08 ± 2.62) and the least one was found in Cough syrup-HVGIC(1.81 ± 0.74) pairwise. The color change observed in Cough syrup-Alkasite group was statistically significantly higher than in Cough syrup-HVGIC (p < 0.05). Alkasite showed greater color alteration with all drugs compared to other materials and HVGIC showed better color stability with all drug formulations.

The piezoelectric property was found by Curie brothers in quartz and Rachel salt (1881). This property is a complicated phenomenon that makes it challenging to study. In 1935, the piezoelectric properties of potassium-dehydrogenated phosphate, the first famous piezoelectric material, were determined. Study about these properties of materials was developed by USA, Russia, and Japan during the Second World War, resulting in some piezoelectric materials such as barium titanate (BT) and lead zirconate titanate (PZT) in 1940 and 1950, respectively. Pure and doped PZT families have been widely studied in ceramics and nanostructured forms to enhance their piezoelectric properties. Because of the lead, the PZT materials are harmful to the environment. Therefore, it has been tried to replace it with suitable lead-free materials for practical purposes. The first lead-free piezoelectric material investigated in this respect is BT. However, the piezoelectric properties of BT are not as good as PZT, so a new generation of lead-free piezoelectric materials has been developed. These new lead-free piezoelectric materials are divided into two categories: (1) the lead-free piezoelectric material based on BNT (bismuth niobium titanate) and (2) the lead-free piezoelectric material based on KNN (potassium sodium niobite). The most significant advantage of these materials is that they are environmentally friendly, but their piezoelectric properties are less than PZT. In this chapter review, lead-based and lead-free piezoelectric materials such as PZT, BT, BZT, KNN, BNT, and ZnO are studied. The synthesized methods of piezoelectric materials in ceramic and nanostructure forms are presented. The applications of piezoelectric ceramics and nanostructures are discussed.

This study involves preparation of self-glazed ceramic tiles by utilizing soda-lime-silica waste glass (SLS). To investigate the effect of addition of SLS with the partial substitution of clay material, three batch compositions were prepared and subjected to seven different temperatures (1050 °C, 1075 °C, 1100 °C, 1125 °C, 1150 °C, 1175 °C, 1200 °C, 1225 °C). Linear shrinkage, glossiness, modulus of rupture, and water absorption of prepared samples showed different behavior at different temperatures. XRD, UTM, and SEM instruments were employed to characterize the developed sample as well as to determine the optimum conditions for the process. For batch 2, best results were observed with value of modulus of rupture 73.35 MPa at low sintering temperature (1100 °C). The obtained result clearly exhibited the efficacy of developed self-glazed ceramic tiles as a cost-effective product and solution to waste glass management.