MECHANISM OF PHASE-FORMATION IN PB(ZRXTI1-X)O-3 SYNTHESIZED BY A PARTIAL OXALATE METHOD

The phase formation mechanism, as well as the morpho-tropic phase boun dary, of lead zirconate titanate (PZT) processed by a partial oxalate method was investigated by simultaneous thermal analysis (TG-DTA) and by qualitative and quantitative X-ray diffraction (XRD), The results s how that the ZrxTi1-xO2 (ZT) phase reacts with PbO forming the PZT pha se without intermediate phases. XRD analysis showed the coexistence of rhombohedral and tetragonal phases for 0.47 less than or equal to x l ess than or equal to 0.55 with the phase boundary composition for x = 0.51, For low calcination temperatures, preferential formation of the PZT rhombohedral phase was observed. A model for phase formation of PZ T by the partial oxalate method is proposed based on the existence of two interfaces of reaction (PbO-PZT and PZT-ZT) and diffusion of catio ns.