单─厚度振动模式压电多晶体及其应用

Extraordinary Piezoelectric Anisotropy in PZT Ceramics and Its Applications

研究了溶胶－凝胶超细粉体合成技术制备的锆钛酸铅（ＰＺＴ）固溶系多晶体和用不同纯度氧化物原材料由固相反应法制备的掺杂钛酸铅（ＰＴ）多晶体的压电各向异性性质。压电各向异性随组分偏离四方─—菱方相界（ＭＰＢ）而增大。实验证明：用氧化物固相反应技术，可获得Ｋ＿ｔ／Ｋ＿ｐ＝∞的钙Ａ位固溶改性ＰＴ组分多晶材料。论文还研究了这种材料的结晶特性、相变特性和介电特性，及相互之间的关系；比较了传输线法或谐振频谱法，计算机辅助导纳圆国法和Ｓｍｉｔｓ法的各种压电参数测试结果。对于Ｑ＿ｍ＜１００的压电晶体，导纳圆图测量法是一种十分准确的测量方法。

Piezoelectric propert ies of purepiezoelectric lead zirconate-titanate(PZT)ceramicsamples at compositions across the ferroelectricregion of the phase diagram from Sol-Gel derived finepowders and Ca-doped lead titanate compositionswere studied. Extraordinary piezoelectric anisotropicceramics with K_t/K_p=∞had been successfullyfabricated.It was found that the piezoelectricanisotropy was very compositional and processingdependent.And it was demonstrated experimentallythat the elimination of microcrack inside ceramic bodywas. the key to have a pure thickness vibration modeof piezoelectric anisotropic ceramic vibrators withoutspurious response.Three kinds of piezoelectricproperty measurement techniques were carried outand compared with.Circle measurement technique isavery precise measurement method for low Q_m andweak piezoelectric effect piezoelectric materials.