Ceramics-Silikáty 50 (4) 225-231 (2006)

Densification and grain growth of SrO-doped ZnO

K. Güntürkün, H. Ö. Toplan

The grain growth kinetics in the 1, 2, 3 and 4 wt.% SrO doped ZnO was studied using the simplified phenomenological grain growth kinetics equation Gn - G0n = K0 •t •exp(-Q/RT) together with microstructure properties and densification of the sintered samples. The grain growth exponent values (n) were found to be 5 for 1, 2, 3 and 4 wt.% SrO doped ZnO. The apparent activation energies for 1, 2, 3 and 4 wt.% SrO doped ZnO were found 780 kJ/mol, 709 kJ/mol, 764 kJ/mol and 744 kJ/mol, respectively. The apparent activation energy was increased with doping of SrO because of ZnSrO₂ phase at the grain boundaries. This ZnSrO₂ phase inhibited the grain growth of ZnO. But the increasing SrO level had no effect on the grain growth. Also, the increasing of SrO resulted in a slight reduction in densification at all temperatures.

Keywords: ZnO, varistor, SrOB Bdoping, Grain growth kinetics, Densification