Grain growth in MnO-added ZnO-6 wt% Bi2O3 ceramic system

Abstract

The grain growth kinetics in the 0-5wt% MnO-added ZnO-6wt% Bi2O3 system was studied using the simplified phenomenological grain growth kinetics equation G(n) = K-o.t. exp(-Q/RT) together with the physical properties of the sintered samples. The grain growth exponent value (n) and the apparent activation energy for the ZnO-6wt% Bi2O3 system was found to be 5 and 200 kJ mol(-1), respectively. These values support the published data for the grain growth mechanism of the ion diffusion model in liquid phase sintering. The addition of MnO lowered the grain growth exponent value to 4 and the apparent activation energy for the grain growth process was increased systematically from 200 kJ mol(-1) to 250 kJ mol(-1) for the additions of MnO from 0 to 5 wt%. This was attributed to the reduction of the equilibrium solubility of ZnO in liquid Bi2O3 phase present between the ZnO grains during sintering. (C) 1997 Published by Elsevier Science Limited.