两步沉淀法合成钙钛矿相锆钛酸铅粉体及其相形成机制

SYNTHESIS AND PHASE FORMATION MECHANISM OF PEROVSKITE LEAD ZIRCONATE TITANATE POWDER BY TWO-STAGE PRECIPITATION

用两步沉淀法低温合成了纯钙钛矿相锆钛酸铅(PbZr0.52Ti0.48O3,PZT)粉体,并利用差热分析测定了合成粉体的反应活化能,从动力学上研究了钙钛矿相PZT的形成机制。结果表明:两步沉淀法合成PZT粉体遵循连续反应机理,在热处理过程中,前驱体粉体在500℃处理后主要形成钙钛矿相,并伴有少量焦绿石相。经600℃煅烧后则完全转化为钙钛矿相。这是由于形成焦绿石相的反应活化能远大于焦绿石相转化为钙钛矿相的反应活化能,因此500℃处理后生成的少量焦绿石相在600℃处理后完全转化为钙钛矿相。

Pure perovskite phase lead zirconate titanate （PbZr0.52Ti0.48O3, PZT） powder was synthesized by two-stage precipitation at low temperature, and the kineties of the perovskite PZT phase formation was investigated by measuring the reaction active energy via differential thermal analysis. The results demonstrated that the precursor to perovskite phase transformation obtained by the two-stage precipitation method follows a consecutive mechanism; that is, the precursor powder first forms perovskite phase with a small amount of pyrochlore phase after heat-treatment at 500℃, and then completely forms perovskite PZT phase after heat treatment at 600℃. Since the active energy for the formation of pyrochlore is much higher than the active energy for the transformation from pyrochiore to perovskite PZT phase, thus the small amount of the pyrochlore phase formed after treatment at 500℃ completely transforms to perovskite phase after treatment at 600℃.