Papers by Author: Yoshiki Yoshioka

Abstract: Synthesis of titanium carbide ceramic powders and control of particle size were tried by carbothermic reduction of a precursor, comparing synthesis of silicon carbide from a precursor. Metal alkoxides were used as a metal source and phenolic resin was done as a carbon source. Homogeneous sol-like mixture was obtained by mixing ethylsilicate and phenolic resin with alcohol. Gel-like precursor was formed by drying the sol-like mixture. Precipitation was formed by mixing titanium(IV) tetraisopropoxide and phenolic resin. The precursor was amorphous and ceramization occurred by heat treatment in argon flow. Growth of particles and phase formation were investigated.

Abstract: Nano sized SiC powder was successfully synthesized by the carbothermal reduction in SiO2. Precursor for SiC was prepared by using phenolic resin as a carbon source and ethylsilicate as a silicon source. After mixing, hydrolysis, drying and pyrolysis at 1000°C, SiC precursor consisted of C and SiO2 was obtained. The precursor was heat treated at 1500-1800°C in Ar to synthesize SiC by the carbothermal reduction. The carbothermal redction reaction was almost completed at 1700°C and then SiC particle with suitable size was obtained at this temperature. Nano-sized SiC particles could be achieved at 1600 °C, and unreacted SiO2 and C remained in the sample. Pure SiC particles were obtained by oxidation and acid treatment. Nano-sized SiC powder had the diameter of 10-20 nm and BET surface area of 156 m²/g.