压电陶瓷振子的谐振频率温度稳定性分析

本文由压电陶瓷中铁电畴极化取向的程度以及绝热条件下的压电方程组出发,推导出压电陶瓷振子谐振频率温度系数T_kf以晶格热膨胀系数、剩余极化强度等为变量的表达式。用“纯”Pb(Zr_xTi_1-x)O₃(锆钛酸铅)的实验数据代入表达式计算,得到准同型相界附近组成的T_kf对Zr/Ti的关系曲线,与实验结果较好地符合。由本文的结论,成功地解释了极化工艺及热处理工艺对T_kf的影响,并讨论了改善压电陶瓷的频率温度稳定性的可能途径。

TEMPERATURE STABILITY ANALYSIS OF THE RESONANT FREQUENCY OF A PIEZOELECTRIC CERAMIC VIBRATOR

The temperature coefficient of resonant frequency T_kf is obtained from the degree of ferroelectric domains alignment in piezoelectric ceramics and the adiabatic. piezoelec-tric equations. It is expressed as a function of the temperature expansion coefficients of the crystal lattice, their remanent polarization and other parameters. When the experi-mental data of "pure" Pb(Zr_xTi_1-x)O₃ are substituted in the theoretical expressions, curves showing Tkf as a function of the Zr/Ti composition near the morphotropic phase boundary are obtained, and the theoretical results are found to be in close agreement with experiment. Thus the effects of different poling and heat treatment processes upon T_kf have been explained successfully. A discussion is given concerning the ways and means by which the resonant frequency temperature stability of piezoelectric ceramic vibrators can be improved.