Densification and grain growth of SiO2-doped ZnO

Abstract

The grain growth kinetics in the 1, 2, 3 and 4 wt.% SiO2 doped ZnO Was Studied Using the simplified phenomenological grain growth kinetics equation G(n) - G(n)(o) = K(o)texp(-Q/RT) together with microstructure properties and densification of the sintered samples. The grain growth exponent values (n) were found to be 3 for 1 wt% SiO2 doped ZnO, 6 for 2 and 3 wt.% SiO2 doped ZnO and 7 for 4 wt.% SiO2 doped ZnO. The apparent activation energy of 486 kJ/mol was Found for 1 wt.% SiO2 added system. A sharp increase in the apparent activation energy to a Value Of 900, 840 and 935 kJ/mol Was found for 2, 3 and 4 wt-% SiO2 added system, respectively. The apparent activation energy was increased with doping of SiO2 because of the formation of spinel Zn2SiO4 phase at the g-rain boundaries. This spinel phase inhibited the grain growth of ZnO. Also densification decreased with increasing SiO2 doping (C) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.