Electromechanical properties of lead zirconate titanatepiezoceramics under the influence of mechanical stresses

摘要

In lead zirconate titanate piezoceramics, external stresses canncause substantial changes in the piezoelectric coefficients, dielectricnconstant, and elastic compliance due to nonlinear effects and stressndepoling effects. In both soft and hard PZT piezoceramics, the aging cannproduce a memory effect that will facilitate the recovery of the polednstate in the ceramics from momentary electric or stress depoling. Innhard PZT ceramics, the local defect fields built up during the agingnprocess can stabilize the ceramic against external stress depoling thatnresults in a marked increase in the piezoelectric coefficient andnelectromechanical coupling factor in the ceramic under the stress.nAlthough soft PZT ceramics can be easily stress depoled (losingnpiezoelectricity), a DC bias electric field, parallel to the originalnpoling direction, can be employed to maintain the ceramic poling statenso that the ceramic can be used at high stresses without depoling