Silicon carbide composites deposited in silicon carbide whiskers by CVI process

Chemical vapor deposition (CVD) is an effective method of preparing silicon carbide whiskers or films and chemical vapor infiltration (CVI) can be successfully used as the preparation of SiC composites. In this paper, silicon carbides whiskers were firstly deposited on reaction-bonded silicon carbide (RB-SiC) substrates under different flow rate of dilute gas by CVD process, and then silicon carbide composites were prepared by chemical vapor infiltration in the as-obtained SiC whiskers in an upright chemical vapor deposition furnace of Π150mm × 450mm with methyltri-chloride silicane (MTS) as precursor gas, H₂ as carrier gas and Ar as dilute gas. The morphologies of the SiC whiskers grown on RB-SiC substrate and SiC composites infiltrated in SiC whiskers were determined by scanning electron microscope (SEM), and the crystalline phase of the final deposits were confirmed with X-ray diffractometry (XRD). As a result, the whiskers with a diameter of about 2μm were deposited on the surface of RB-SiC substrate, and the curly defects of whiskers decrease with the addition of dilute gas. And by chemical vapor infiltration in as-prepared SiC whiskers, the SiC composites were successfully prepared. Finally the deposits were determined as β-SiC.