Abstract
When we sinter ceramic powder, we often add seed grains to grow selected grains. It is very important for such microstructural design to know their grain sizes and the amount of addition. Grain growth behavior of large grains in a matrix with small grains is studied to understand a role of seed grains. We first postulate that excess free energy of a solid drives mass-transport to decrease total free energy. This concept yields new rate equation for mass transport which is applied to the grain growth phenomenon of ceramic powder. We use the Ostwald ripening model for the study. From the model and the free energy theory, rate equations for grain growth are derived, and growth rates are calculated numerically. We will discuss optimum grain size and the amount of addition of seed grains from the results of calculations.
