(Pb_(0.85)Sm_(0.10))(Ti_(0.98)Mn_(0.02))O_3压电陶瓷超高各向异性机电耦合性能的X射线衍射研究

AN X Ray Diffraction STUDY ON THE ULTRA-HIGH ELECT-ROMECHANICAL ANISOTROPY IN (Pb_(0.85)Sm_(0.10))(Ti_(0.98)Mn_(0.02)2)O3 PIEZOELECTRIC CERAMICS

本文用X射线衍射技术研究了具有典型超高各向异性机电耦合性能的Sm改性PbTiO_3压电陶瓷。通过引入面网取向密度指数ρ_(hkl)和建立90°电畴转向畴壁平移模型,就改性PbTiO_3陶瓷圆片经不同电压极化后材料内部电畴结构变化作了定量的分析与讨论。结果表明,在改性PbTiO_3陶瓷结构中,90°畴壁空间取向分布具有高度的择优性;极化处理使材料中90°电畴壁显著平移,但其取向分布变化甚少;材料的纵向机电耦合系数K_1与(002)面网取向密度指数增量△ρ_(002)具有基本平行的电场依赖关系。

XRD technique was employed to examine Sm-modified PbTiO3 piezoelectric ceramics with typical ultra-high electromechanical anisotropy. By introducing crystal plane orientation density ρ(hkl) and establishing wall translation model for 90°ferroelectric domain switching, a quantitative analysis and discussion on the domain texture change within the ceramic disks poled at various electric forces has been carried out. The results indicate that 90°domain walls in the modified PbTiO3 ceramics show a strong spatial orientation preference, and little changes in their orientation can result from poling treatment but noticeable wall displacement appears. Another noteworthy result is that the thickness electromechanical coupling coefficient Kt develops with poling field almost at the same pace as the orientation density gain △ρ(002) of the crystal plane (002).