Abstract: SiC-TiC ultrafine powder was synthesized by a carbothermal reduction method using SiC, TiO2 and different types of carbon source as raw materials.The effects of different carbon sources and calcination temperatures on the phase composition and microstructure of SiC-TiC ultrafine powder were discussed.The synthesized powders were characterized by X-ray diffraction (XRD), laser particle size analyzer and scanning electron microscope (SEM).The experimental results show that the suitable conditions for the preparation of SiC-TiC ultrafine powder with sucrose as carbon source is at 1450 ℃ for 2 h.The optimum condition for the preparation of SiC-TiC ultrafine powder with carbon black or glucose as carbon source is at 1500 ℃ for 2 h.SiC-TiC superfine powder possess the smallest particle size when carbon black is used as a carbon source in three kinds of carbon sources.The particles of SiC-TiC superfine powder are dispersive with particle size of 0.5-1.0 μm.In-situ synthesized TiC particles in SiC powders exist in irregularly diversified structure particles with particle sizes of 0.1-0.2 μm.

Key words: SiC-TiC ultrafine powder was synthesized by a carbothermal reduction method using SiC, TiO2 and different types of carbon source as raw materials.The effects of different carbon sources and calcination temperatures on the phase composition and microstructure of SiC-TiC ultrafine powder were discussed.The synthesized powders were characterized by X-ray diffraction (XRD), laser particle size analyzer and scanning electron microscope (SEM).The experimental results show that the suitable conditions for the preparation of SiC-TiC ultrafine powder with sucrose as carbon source is at 1450 ℃ for 2 h.The optimum condition for the preparation of SiC-TiC ultrafine powder with carbon black or glucose as carbon source is at 1500 ℃ for 2 h.SiC-TiC superfine powder possess the smallest particle size when carbon black is used as a carbon source in three kinds of carbon sources.The particles of SiC-TiC superfine powder are dispersive with particle size of 0.5-1.0 μm.In-situ synthesized TiC particles in SiC powders exist in irregularly diversified structure particles with particle sizes of 0.1-0.2 μm.