GRAIN-GROWTH IN MNO-ADDED ZNO-6 WT-PERCENT BI2O3 CERAMIC SYSTEM

The grain growth kinetics in the 0-5wt% MnO-added ZnO-6wt% Bi2O3 syste m was studied using the simplified phenomenological grain growth kinet ics equation G(n) = K-o.t. exp(-Q/RT) together with the physical prope rties of the sintered samples. The grain growth exponent value (n) and the apparent activation energy for the ZnO-6wt% Bi2O3 system was foun d to be 5 and 200 kJ mol(-1), respectively. These values support the p ublished data for the grain growth mechanism of the ion diffusion mode l in liquid phase sintering. The addition of MnO lowered the grain gro wth exponent value to 4 and the apparent activation energy for the gra in 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 attr ibuted 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.