用X射线衍射(X-ray diffraction,XRD)研究了两步沉淀法合成钙钛矿相锆钛酸铅(PbZrxTi1–xO3,PZT)的相形成机理和准结晶学相界。结果显示:两步沉淀法合成的PZT粉体为纯钙钛矿相,低温煅烧时,优先形成菱方相PZT。XRD分析结果表明:900℃煅烧合成的PZT粉体,摩尔组成在0.47≤x≤0.55范围时,菱方相和四方相共存,两相相等的组成点为x=0.515。基于PbO–PZT和PZT–ZrxTi1–xO3(ZT)2个反应界面以及离子扩散,提出了关于两步沉淀法合成PZT相形成反应机理的模型。
The phase formation mechanism and the morphotropic phase boundary of lead zirconate titanate (PbZrxTi1-xO3, PZT) prepared by a two-stage precipitation route was investigated by X-ray diffraction (XRD). The results show that the synthesized PZT powders are of pure perovskite phase and at low calcination temperatures, preferential formation of the PZT rhombohedral phase was observed. The XRD analysis revealed the coexistence of rhombohedral and tetragonal phases for 0.47≤x≤0.55, with the phase boundary composition for x=0.515. A model for the phase formation mechanism of PZT by the two-stage precipitation route was proposed based on the existence of two reaction interfaces of PbO-PZT and PZT-ZT as well as the diffusion of cations.