PREPARATION OF Si3N4–20% NbN COMPOSITES BY SPARK PLASMA SINTERING

Abstract

Optimal nitriding parameters of the initial β-Si3N4–39.6% (мас.) Nb powder subjected to preliminary vacuum heat treatment have been established. In the case of nitriding at a temperature of 1400 °С, a highly disperse composite powder containing higher cubic niobium nitride and β-Si3N4 forms. The morphology of the obtained powder has been investigated, and the uniform distribution of niobium nitride in the volume of β-Si3N4 is shown. We have performed the spark plasma sintering of the obtained powder, which has enabled us to obtain a composite ceramic with a hardness of 16.6 ± 0.5 GPa