Anomalous retardation of the sintering kinetics of ZnO with addition o
f Bi4Ti3O12 (BIT) and a low voltage varistor composition containing Zn
O, BIT, Co3O4 and Mn2O3 in the temperature interval between 780 and 85
0-degrees-C was investigated. On the basis of transmission electron mi
croscopic analysis of diffusion couples the retardation of sintering k
inetics was ascribed to surface diffusion of Bi and Ti along ZnO grain
surfaces. Liquid phase formation resulting from chemical reactions be
tween the components triggers exaggerated grain growth. Nucleation and
growth of anomalous grains is influenced by the presence of inversion
boundaries in ZnO grains.