EXTENDED DEFECTS IN ZNO CERAMICS CONTAINING BI4TI3O12 ADDITIVE

Extended defects in ZnO ceramics containing 6 wt% Bi4Ti3O12 were studied by analytical electron microscopy. Apart from basal plane condensation stacking faults, which are also present in as-received ZnO, extended defects related to the presence of Bi4Ti3O12 were observed. In samples sintered at 900-degrees-C they lie in the basal or in the prismatic {1010BAR} planes and they quite often form closed loops, whereas they form serpentine-shaped boundaries in samples sintered at 1200-degrees-C. Evidence is given that they are inversion boundaries. Their TEM image characteristics, as well as the unambiguous presence of Ti at the boundaries, suggest that they are formed due to the presence of 2-D coherent precipitates of Ti-rich (possibly Zn2TiO4-type spinel) phase.