Anisotropic Grain Growth of ZnO Grain in the Varistor System ZnO-Bi2O3-MnO-TiO2

From the analysis of selected-area electron diffraction patterns through transmission electron microscopy, the crystallographic orientation of anisotropic ZnO grain growth by the addition of TiO{sub 2} to the varistor system ZnO-Bi{sub 2}O{sub 3}-MnO was determined to be the (10{anti 1}0) and ({anti 2}110) directions. The behavior of anisotropic grain growth was interpreted by the epitaxial growth of prism planes (resulting from the favorable atomic arrangement on these planes compared with other planes) and the increase in reactivity of the Bi-rich liquid phase toward the ZnO grain by the addition of TiO{sub 2}.