Effects of electric field on the biaxial strength of poled PZT

The mechanical integrity of piezoelectric ceramics plays a crucial role in the performance and design of lead zirconate titanate (PZT) piezo stack actuators especially as PZT actuators become physically larger and are sought to operate under harsher conditions. Reliable design of such systems demands additional consideration of a number of issues including electro-mechanical coupling, as well as strength-size scaling. This study addresses some of those issues through the use of ball-on-ring (BoR) equibiaxial flexure strength tests of two PZT piezo ceramics, subjected to different electric fields. Fracture surfaces and failure origins were analyzed using optical and scanning electronic microscopy. The both sign of the electric field and its magnitude can alter the two-parameter Weibull distribution. These results serve as input data for future probabilistic reliability analysis of multilayer PZT piezo actuators.