Microstructure and growth mechanism of SiC whiskers synthesized by using different raw materials

Using microsilica and Si3N4 as silicon sources,black carbon as carbon source,B2O3 as catalyst,SiC whiskers were synthesized under argon atmosphere at 1500℃ by carbothermal reduction method.Morphology and crystal structure of SiC whiskers were characterized by transmission electron microscope and scanning electron microscope.The results show that the SiC whiskers synthesized by using two kinds of silica sources are both β-SiC single crystals,and the growth plane is(111) along the direction of .The obvious differences in morphology indicate that there are different growth mechanisms of SiC whiskers synthesized by using different silica sources.VLS growth and screw dislocation growth are suitable to explain the differences in morphology of two kinds of SiC whiskers respectively.