Contact materials in high-voltage vacuum interrupters require properties such as high conductivity, density and hardness to minimize arc heat damage. In this study, Cu–Cr–Mo alloy contact materials were examined for their usage as high-voltage contact materials. Ball milling was performed after analyzing the raw materials of the Cu, Cr and Mo powders. A green compact was produced using high pressure with a mixed powder. Subsequently, the composite was produced by sintering via the temperature and infiltration method according to the Cu content in the green compact. The composite sintering method produced a density of 8.55 g/cm³ (relative density 93%), a hardness of 217 HV and an electrical conductivity of 40.7% IACS at 1200 °C. The composite of 10 wt.% Cu produced by the Cu infiltration method exhibited a density of 8.7 g/cm³ (relative density 94%), hardness of 274 HV and electrical conductivity of 39 IACS% at 1300 °C. The measurements of the physical properties of our newly established method demonstrated a new possibility of using the Cu–Cr–Mo alloy as a contact material for high-voltage vacuum interrupters.

Commercial production of titanium involves chlorination using chlorine gas that can be converted to hydrochloric acid by atmospheric moisture and is hazardous to human health. In the titanium production process, self-propagating high-temperature synthesis is one of the process to directly reduce titanium dioxide. In this work, titanium powder was prepared by self-propagating high-temperature synthesis using titanium dioxide as the starting material and magnesium powder as a reducing agent. After the reaction, magnesium and magnesium oxide by-products were then removed by acid leaching under different leaching conditions, leaving behind pure Ti. During each leaching condition, the temperature of the leaching solution was carefully monitored. After leaching, the recovered titanium in the form of a powder was collected, washed with water and dried in a vacuum oven. Detailed compositional, structural, and morphological analyses were performed to determine the presence of residual reaction by-products. It was found that leaching in 0.4 M hydrochloric acid followed by second leaching in 7.5 M hydrochloric acid is the optimum leaching condition. Furthermore, it was also noticed that total volume of solution in 0.4 M hydrochloric acid leaching condition is advantageous to maintain uniform temperature during the process.

Mesoporous materials have gained considerable attention in the fabrication of supercapacitor electrodes because of their large surface areas and controlled porosities. This study reports the synthesis of mesoporous CuCo₂O₄ powders using the inverse micelle method. X-ray diffraction, N₂ sorption measurement, transmission electron microscopy, and X-ray photoelectron spectroscopy were performed to investigate the properties of the powders. After heat treatment at 250 °C in a vacuum atmosphere, the mesoporous CuCo₂O₄ powders exhibited a large specific surface area of 116.32 m² g^-1 and a high crystallinity. The electrode fabricated by using the as-prepared mesoporous CuCo₂O₄ powder exhibited enhanced electrical properties with a maximum specific capacitance of 140 F g^-1 and capacitance retention of 91.4% after 3000 continuous charge-discharge cycles. Therefore, the as-prepared mesoporous CuCo₂O₄ powders hold great potential in the fabrication of supercapacitor electrodes to be used for a wide range of electrochemical applications.

In this study, high-purity tantalum metal powder was manufactured via self-propagating high-temperature synthesis. During the process, Ta2O5 and Mg were used as the raw material powder and the reducing agent, respectively, and given that combustion rate and reaction temperature are important factors that influence the success of this process, these factors were controlled by adding an excessive mass of the reducing agent (Mg) i.e., above the chemical equivalent, rather than by using a separate diluent. It was confirmed that Ta metal powder manufactured after the process was ultimately manufactured 99.98% high purity Ta metal powder with 0.5 µm particle size. Thus, it was observed that adding the reducing reagent in excess favored the manufacture of high-purity Ta powder that can be applied in capacitors.