Grain Growth of Carbide-Based Cermets During Liquid Phase Sintering

The grain growth of carbide phases during liquid phase sintering was investigated for TiC- and WC-base cermets sintered at 1673K for 3.6-44ks. The kinetics of grain growth behaviors of TiC-Ni, TiC-Mo₂C-Ni, WC-Co and WC-VC-Co cermets almost fitted to the cubic relation of d ³ - d ₀ ³ = Kt. The rate constant values of TiC-Mo₂-Co and WC-VC-Co cermets are approximately two or three orders magnitude lower than TiC-Ni and WC-Co cermets. The growth rate constant of carbide phases had a peak at a liquid phase content in TiC-Ni and WC-Co cermets, while it slightly decreased with decreasing liquid content in Mo₂C-and VC-added cermets. The growth rate constant tended to lower with higher contiguity of carbide particles. The grain growth behavior of these cermets could be explained by the mechanism that the existence of contiguous boundaries of carbides particles suppressed the movement of solid/liquid interfaces during liquid phase sintering.