Carbon-bonded carbon fiber composites reinforced with SiOC-based polymer derived ceramics: Microstructure and properties

Abstract

Carbon-bonded carbon fiber (CBCF) composites have been used extensively for lightweight thermal insulation applications. In this work, CBCF composites reinforced with SiOC, B-modified SiOC (SiBOC) or Zr-modified SiOC (SiZrOC) ceramics were investigated. The chemical modification of SiOC precursor has significant effects on the microstructure as well as the mechanical and thermal properties of the composites. The SiBOC and SiZrOC precursor exhibit higher impregnation efficiency than the SiOC precursor. The SiBOC/CBCF composites have the highest compressive strength and best oxidation resistance, which is attributed to its preferable microstructure, where the SiBOC ceramics wrap on the fibers and provide effective protection for carbon fibers from oxygen diffusion. The strength and modulus of SiBOC/CBCF composites along z direction is 4.5 and 148 MPa, respectively. The thermal conductivity and expansion coefficient of SiBOC/CBCF composites along z direction is 0.3 W/m⋅k and 1.75 × 10−6 K−1, respectively.