Microstructure of TiC–TiN–Ni–(B) cermet systems

Abstract

TiC-TiN-Ni-(B) systems were investigated to understand particle coarsening and morphology changes as a function of sintering time and compositions. In addition, the variations in the C/(C+N) ratios of Ti(C_1-xN_x) solid solutions formed in the system were studied. As expected, the particle size becomes larger with an increase in the duration of sintering. However, added boron significantly reduced the growth of particles. X-ray diffraction analysis shows that the binder phase consists largely of Ni₃B in TiC-TiN-20Ni-1B (in wt-%) system. The presence of boron in the liquid Ni seems to interfere with the dissolution of TiC and TiN and/or transport of Ti, C, and N. The effect of boron decreases as the amount of Ni binder increases. The particle morphology is found to change with variations in the C/(C+N) ratio.