The correlation between fatigue and material constants of PLZT ceramics

Correlations between the ferroelectric fatigue and variations in mechanical properties have been investigated by simultaneous measurement of the fatig ue and the piezoelectric resonance of bar 8/65/35 PLZT ceramics. It was fou nd that the fatigue reflects itself only in dielectric and piezoelectric pr operties. Namely, the remanent polarization, the complex dielectric and pie zoelectric constants and the electromechanical coupling factor all start to decrease at the same number of switching cycles. On the other hand, the co mplex elastic compliance remains almost unchanged during fatigue process. I n addition, the electrical, mechanical and electromechanical quality factor s, determined at the piezoelectric resonance frequency, remain constant wit h the increasing number of switching cycles. This suggests that no correlat ion exists between the ferroelectric fatigue process and the mechanical deg radation in 8/65/35 PLZT ceramics. (C) 1999 Elsevier Science Limited. All r ights reserved.