Mechanism of grain growth control in Ti(C, N)-based cermet during sintering
(College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
Abstract: A typical Ti（C, N）-based cermet and another cermet with grain growth inhibitor Cr3C2 were studied using scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, energy dispersive X-ray analysis （EDX）. The two cermets have a “core-rim” structure. The structure is formed by dissolution of small ceramic grains and precipitation of （Ti, Mo, W）（C, N） around the remaining TiC core. Most of chromium element congregated in the rim phase when Cr3C2 was added. During liquid phase sintering Cr3C2 solved in binder phase and congregated around the hard grains, which reduced the solubility of TiC in liquid phase, and consequently restrained the dissolution and reprecipitation, the grains were restrained from growing up during sintering.
Key words: cermet； grain growth inhibitors； microstructure