Constrained sintering of Bi2O3‐doped ZnO

Abstract

AbstractEffects of Bi2O3 on densification kinetics and mechanism of a polycrystalline ZnO ceramics under free and constrained sintering have been investigated. With the presence of 1‐5 wt% Bi2O3, the densification temperature of ZnO is reduced from 1200°C to 850°C under free sintering. Although the densification kinetics of ZnO + 1 wt% Bi2O3 is slowed down due to the presence of in‐plain tensile stress generated during constrained sintering, a high degree of densification of >95% at 950°C is still obtained. The above phenomena are attributed to the formation of Bi2O3‐rich intergranular glassy film at the grain boundaries, yielding a decrease in the grain boundary energy and an increase in the grain boundary migration kinetics of ZnO. Results of molecular dynamics simulation confirm the above observations, at which the ratio of grain boundary energy of ZnO between with and without 1 wt% Bi2O3 is consistent with that obtained experimentally.