Optical coating on Cf/SiC composites via aqueous slurry painting and reaction bonding

Abstract

A novel surface modification method for Cf/SiC composites is proposed with aqueous slurry painting together with reaction bonding. Stable slurries were obtained by dispersing SiC to carbon black in aqueous solution, under centain binder content and solid loading conditions. The results show that porous carbonaceous C/SiC tape with porosity of 49% could be obtained by aqueous slurry painting. Si/SiC coating with high density and strong bonding onto the substrate is realized by infiltrating liquid silicon into the as-prepared tape. A reaction layer of ~15 μm in thickness is formed between the coating and the substrate. This Si/SiC coating exhibits excellent mechanical properties, with HV hardness of (14.19 ± 0.46) GPa and fracture toughness of (3.02 ± 0.30) MPa·m½. The coating is achieved fine surface of 2.97 nm RMS in roughness after precision grinding and polishing.