초록 열기/닫기 버튼
SiC-TiC composite powders were synthesised in argon atmosphere by a carbothermal reduction method using silica sol, TiO2,and different carbon sources (i.e., graphite and starch) as the raw materials. The effects of carbon source types and reactiontemperatures on the phase composition, particle size distribution, and microstructure of SiC-TiC composite powders wereinvestigated. The reaction mechanism of SiC-TiC composite powders was also discussed. Results showed that SiC-TiCcomposite powders can be synthesized under optimum conditions (i.e., 1600 oC for 2 hrs using graphite as carbon source and1550 oC for 2 hrs using starch as carbon source). The SiC-TiC composite powders prepared at 1600 oC comprised a smallamount of large-sized tabular grains, a large number of fine irregular rod-like and approximately spherical particles 200-400 nm in size using graphite as carbon source. The SiC-TiC composite powders prepared at 1550 oC were composed of flakyparticles, spherical particles (~ 100-200 nm), and whiskers (50-200 nm in diameter) using starch as carbon source. The growthmechanism of SiC whiskers synthesised in powder samples followed the vapor-solid mechanism.
