Microstructural characterization and computer simulation of conductivity in Si3N4-TiN composites

Abstract

Si3N4-TiN ceramics sintered with Y2O3 and Y2O3 + Al2O3 as sintering aids and various content of TiN (0-50 wt.%) were investigated regarding their microstructural and electrical properties. Electroconductive composites were obtained with TiN content higher than 20 vol.%. Computer simulation of conductivity versus concentration of TiN has been done in respect of different models. The influence of dimensionality and type of conductive network on the critical exponent s in the power law, which describes the conductivity of composites, has been discussed. The addition of beta-Si3N4 seeds affected fracture toughness in Si3N4-36 wt.% TiN composites while only a slight change in electroconductivity of the composites was observed at the same time. (C) 2003 Elsevier B.V. All rights reserved.