Morphology of SiC Whisker in Whisker Reinforced Reaction Bonded SiC Composite

Abstract

SiC whisker was introduced into reaction bonded silicon carbide to produce high performances composite by slip casting and reaction sintering. This study aimed at morphology of SiC whisker in the reaction bonded silicon carbide ceramics. The whisker was homogeneously dispersed into SiC/C suspension by ball-milling and ultrasonic dispersion. By chemical etching, the whisker displays the original burl profile on the polished surface of the composite. The raise of whisker fraction leads to an increase of porosity of the green body; and thus a decrease of density of the sintered body. For the specimen with 25 wt.% whisker, the rapid reaction of carbon with excess molten silicon leads to the missing of burl profile on the whisker surface. It is speculated that β-SiC on the whisker surface dissolved in the molten silicon during liquid silicon infiltration.