Densification and grain,growth of TiO2-doped ZnO

Abstract

The kinetics of grain growth in 1-4 wt. % TiO2-doped ZnO was studied using the simplified phenomenological grain growth kinetics equation together with examination of microstructure and densification of the sintered samples. The grain growth exponent values n were found to be 3 for I and 2 wt. % TiO2-doped ZnO, 5 for 3 and 4 wt. % TiO2-doped ZnO. The apparent activation energy of 435 kJ/mol was found for I and 2 wt. % of TiO2 in ZnO. It was found to be 608 kJ/mol, and 615 kJ/mol for 3 and 4 wt. % TiO2, respectively. The apparent activation energy increased with TiO2 content due to formation of spinel Zn2TiO4 phase at the grain boundaries which inhibited the grain growth of ZnO. Also densification decreased with increasing TiO2 content.