Spark Plasma Sintering of Si3N4/C Composites

Abstract

Abstract Si3N4/C composites were prepared with carbon black and α-Si3N4 powder by a novel sintering method, i.e. spark plasma sintering. SiC particles formed through reactions between the carbon particles and the SiO2 on the Si3N4 surface. The samples were sintered at 1650 °C for 5 minutes in a nitrogen atmosphere. The microstructure, phase composition, mechanical properties, and dielectric properties of the composites were investigated. The relative densities of the C/Si3N4 composites decreased from 99 to 85% when the carbon black content increased from 0 to 20 wt.-%. Bending strength, hardness and dielectric properties were found to be influenced by the amount of carbon black introduced into the silicon nitride matrix.