Sintering and grain growth kinetics of ball milled nanocrystalline nickel powder

Detailed studies on the sintering and grain growth of ball milled nanocrystalline nickel power were carried out. The analysis of grain coarsening process was found to be very helpful for understanding the sintering mechanisms. The explosive grain growth was observed at higher temperature and the activation energy of grain growth increased with increasing temperature. The grain boundary diffusion was identified as grain growth mechanism at lower temperatures. This powder showed very low activation energy of sintering (66.2 ± 3 kJ mol−1). The surface diffusion was found as dominating mechanism through out the sintering. At higher temperatures lattice diffusion was found to be controlling both, sintering and grain growth.