Carbothermic reduction of a columbite concentrate to produce cemented carbides and metal-matrix composites

The study of the carbothermic reduction of a columbite concentrate was carried out to form cemented carbides based on particles of (Nb, Ta)C solid solution bonded together by ferromanganese. The effect of various parameters on the kinetics of reaction were examined. Complete wetting of the carbide phase by the metal was achieved. Metal-matrix composites (MMC) based on (Nb, Ta)C and cast iron were also obtained and the morphology is described. Addition of Ni to the MMC had a profound effect on the microstructure and carbide distribution in the matrix