High strength and toughness electroconductive SiC-based composites

Abstract

The development of silicon carbide (SiC) based composites using MoSi 2 as the secondary electroconductive phase for the matrix was investigated. A mixture of SiC and 10 vol % MoSi2 was hot pressed at 1900°C, without any addition of sintering aids. An improvement of the final; relative density from 60 to 86% was obtained with the addition of 2 wt% of Y2O3. In the reinforced composite containing 30 vol% of MoSi2, the fracture toughness increased of about 27 % in comparison with the reference SiC material. It was observed that the addition of MoSi 2 particles to the Sic matrix caused a gradual decrease of the electrical resistivity of the composites. The hardness of the composites decreased with increasing the MoSi2 content, while the Young's Modulus existed near the SiC reference value