Preparation of C_f/SiC Composites by Chemical Liquid-Vapor Deposition Process

摘要

The conversion of the liquid polycabosilane (LPCS) into silicon carbide was investigated by IR, XRD, which indicated the feasibility of the transition from LPCS to SiC ceramics above 900°C. The FTIR spectra and XRD patterns of the C_f/SiC composites show that the matrix deposited at 1200°C has silicon carbide structure with the crystallite size of β-SiC phase of about 41 nm, while the SiC phase is amorphous at 900°C. The carbon fiber reinforced silicon carbide composites (C_f/SiC) were hereby prepared at 900°C and 1200°C, through chemical liquid-vapor deposition (CLVD) process using LPCS as precursor. Flexural strength of 224 MPa for Cf/SiC specimen with density of 1.81g·cm~(-3) was obtained after being prepared at 1200°C for 30 minutes. The load-deflection curve has shown that the fracture behavior of the C_f/SiC composites is a typical non-brittleness. The results indicate that the CLVD process has a great advantage and prospect to prepare C_f/SiC composites in future.