Surface Modification of Silicon Carbide Powder with Silica Coating by Rotary Chemical Vapor Deposition

The surface of silicon carbide (SiC) powder was modified by coating with amorphous silica (SiO2) using (C2H5O4) Si (tetraethyl orthosilicate: TEOS) as a precursor by rotary chemical vapor deposition (RCVD). With increasing deposition time from 0.9 to 14.4 ks, the mass content of SiO2 coating increased from 1 to 35 mass%. The SiO2 mass content had a linear relationship with deposition time from 2.7 to 7.2 ks. The effects of O-2 gas flow, deposition temperature (T-dep), total pressure (P-tot) and precursor vaporization temperature (T-vap) on the SiO2 yield by RCVD were investigated. At O-2 gas flow of 4.2 x 10(-7) m(3) s(-1), Tdep of 948 K, Ptot of 400 Pa and deposition time of 7.2 ks, the maximum SiO2 yield of 1.82 x 10(-7) kg/s with SiC powder of 4.5 x 10(-3) kg by RCVD was obtained.