Novel electrically conductive α–β SiAlON/TiCN composites

Abstract

Electrically conductive α–β SiAlON/TiCN composites were produced in the form of a segregated network in a ceramic matrix structure. A continuous 3D network of conductive TiCN particles was successfully achieved by mechanically coating spray-dried SiAlON granules with varying amounts of nano sized TiCN (0–10vol.%) particles. For comparison, the same SiAlON matrix was incorporated with 25vol.% micron sized TiCN particles to give a particle reinforced composite. Densification, together with mechanical and electrical properties of the composites produced were discussed in terms of conventional and novel approach. Fully dense composites were obtained by gas pressure sintering (GPS) under a nitrogen pressure of 100bar at a peak temperature of 1990°C. The electrical resistivity of the SiAlON (1×1013Ωm) matrix material was drastically reduced with the addition of only 5vol.% TiCN (18×10−4Ωm) to the composites prepared by the coating method.