Sol-gel process doped ZnO nanopowders and their grain growth

The doped ZnO nanoparticles are prepared by sol-gel method. These ZnO nanoparticles provide ZnO-based ceramic varistors displaying superior varistor properties—higher value of the nonlinear coefficient, lower leakage current, and higher critical electric field values—as compared to those of conventional samples. The present work has been aimed at studying the effect of processing variables such as sintering temperature and duration on the microstructure and grain growth of ZnO-Bi2O3-Sb2O3-MnO2-Co2O3-A12O3 ceramics. The activation energy calculated is found to be 364 ± 24 KJmol for Bi2O3-Sb2O3-MnO2-Co2O3-Al2O3 doped ZnO. All these advantages are due to greater structural homogeneity, smaller particle size, higher surface area, and higher density of the doped ZnO nanoparticles which are precursors for ZnO varistors, as compared to coarser particles for making varistors.