PZT陶瓷中由氧空位与畴壁相互作用引起的内耗

Internal friction due to the interaction between oxygen vacancies and domain boundaries in PZT ceramics

采用低频倒置扭摆内耗仪对组分为 Pb(Zr0.7Ti0.3)O3 (PZT73)和 Pb(Zr0.3Ti0.7)O3 (PZT37) 的两种陶瓷的内耗 Q-1及振动频率的平方 f 2（正比于材料的剪切模量 G）与温度的关系进行了 测定。在纯三角相的 PZT73陶瓷中发现两个内耗峰。高温内耗峰 PM起源于材料的顺电－铁 电相变 ,低温内耗峰 P1本质上是一个宽化的 Debye峰，可归因于氧空位作用下的畴壁振荡弛豫。 对纯四方相的 PZT37陶瓷，除了 P1和 PM峰外，在 P1与 PM峰之间另有内耗峰 P2，这与 900畴附 近的氧空位团簇的弛豫有关 ,其特征可用描述强关联系统的关联态模型（ Coupling model）描述。

The internal friction Q-1 and the square of vibration frequency f 2(proportional to shear modulus G) were measured as a function of temperature on undoped Pb(Zr0.7Ti0.3)O3 (PZT73) and Pb(Zr0.3Ti0.7) O3 (PZT37) ceramics from 200C to 5000C. Experiments were performed on an inverted torsion pendulum at low frequencies (1～ 5Hz) .Two internal friction peaks were found in pure rhombohedral PZT73 ceramics. The high temperature peak PM, which appears at the Curie temperature, originates from the para-ferroelec- tric phase transition. The low temperature peak P1 is a broadened Debye peak in nature, and it is contri- buted to the oscillation damping of the domain walls locked by the oxygen vacancies. For the pure tetrago- nal PZT37 ceramics, another peak P2,which appears between P1 and PM,can be well described by the coup- ling model. It is thought to be related with the relaxation of oxygen vacancy clusters near the 900 domains.