Preparation of Carbon/Ceramic Composite Materials by Use of Raw Coke (Part 9)

Mechanical and Thermal Properties of C/SiC/B₄C Composites

Abstract

Mechanical and thermal properties of the C/SiC/B₄C composites made by a normal pressure sintering process were examined as a function of SiC and B₄C content. The composites showed an increase in bending strength due to dispersions of the particles, which was more markedly than that of the composites made by hot press method. The increase in mechanical strength was due to not interactions between cracks and dispersed particles but an increase in Young's modulus of the composites. The thermal expansion coefficient decreased with an increase of SiC and B₄C content, which showed the same feature in temperature dependence as conventional carbon bodies, that is, the slopes of the increases became small at around 400°C. The particle dispersions of SiC and B₄C improved the thermal conductivity at room temperatures. Thermal shock fracture resistance, R and R′, showed the maximum values when the SiC and B₄C content was around 30vol%.