Grain growth kinetics in the xAl(2)O(3)-6wt. % Bi2O3-(94-x) ZnO (x=0, 2, 4) ceramic system

Abstract

The effects of the amount of Al2O3 (0, 2 and 4 wt.%) on the microstructural properties have been studied in a binary ZnO-6 wt% Bi2O3 system. The microstructure of the samples consists mainly of ZnO grains with beta-Bi2O3 and ZnAl2O4 spinel as the secondary phases. The grain growth kinetics in the 0, 2 and 4 wt.% Al2O3 added ZnO-6 wt.% Bi2O3 system were studied using the simplified phenomenological grain growth kinetics equation together with the physical properties of the sintered samples. The grain growth exponent value (n) and the apparent activation energy for the ZnO-6 wt.% Bi2O3 system were 5 and 218 kJ/mol, respectively. The addition of the Al2O3 to the ZnO-6 wt.% Bi2O3 System inhibited the ZnO grain growth. At 2 and 4 wt.% Al2O3 additions, the apparent activation energies were calculated as 341 and 578 kJ/mol respectively. The addition of Al2O3 to the system inhibited the grain growth of ZnO ceramics.