Grain growth of ZnO–V2O5 based varistor ceramics with different antimony dopants

Grain growth of 2 wt% V2O5/Sb2O3 precursor doped ZnO–V2O5 based ceramics was studied for sintering from 900 to 1050 °C. The results are discussed and compared with those of the conventional Sb2O3 doped ZnO–V2O5 based ones of the same stoichiometric ratio in terms of the phenomenological grain growth kinetics equation: Gn−G0n=K0t exp(−Q/RT). Grain growth exponent and apparent activation energy of the precursor doped ceramics are found to be 2.44 and about 218 kJ/mol, respectively, much lower than 4.03 and about 365 kJ/mol for the Sb2O3 doped samples. This result and the XRPD examination of the phase transformation within two extra batches of the precursor or the Sb2O3 slightly over-doped samples sintered at 550–900 °C for 1 h indicate the elimination of Sb2O3 related films contributes mainly to the observed noteworthy low temperature sintering (900 °C) of the precursor doped ZnO–V2O5 ceramics.