Faceting at ZnO-Bi_2O_3 Interphase Boundaries in ZnO-based Varistor Ceramics

摘要

ZnO-based varistor ceramics containing Bi_2O_3, Sb_2O_3, MnO and Co_3O_4 obtained by water quenching from the sintering temperature of 1250 deg C show extensive faceting at ZnO - delta-Bi_2O_3 interfaces. Trace analysis showed that facets are the ZnO basal plane, ZnO prism planes or low index pyrmaidal planes. The most prominent facets were generally found to be the ZnO prism planes which are populated by equal proportions of zinc and oxygen atoms and are thus relatively favoured low energy planes.