In-situ combustion synthesis and densification of TiC– xNi cermets

Abstract

The combustion synthesis reaction was combined with quasi-isostatic pressing (QIP) technique to fabricate full density TiC– xNi composites in a single processing operation. Combustion wave velocity and temperature of Ti–C–Ni were measured and the microstructure of the product was characterized by X-ray diffraction and scanning electron microscopy. With increasing Ni content in TiC– xNi, both the combustion wave velocity and temperature decrease. The Ni additive, mainly as a diluent and the binder of TiC grains in a matrix, formed a quasi-continuous phase enveloping spheroidal TiC particles and brought about a grain size decrease from 9 to 1 μm. TiC-20 wt% Ni cermet produced by the combustion synthesis/quasi-isostatic pressing process under 160 MPa for 20 s show near full density, high hardness and transverse rupture strength (1024.2 MPa).