EXTENDED DEFECTS IN ZNO CERAMICS CONTAINING BI4TI3O12 ADDITIVE

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