Influence of Microcracking and Slow Crack Growth on the Planar Coupling Coefficient in PZT

Abstract

The difference in the planar coupling coefficient, kp, of two PZT specimens with different grain sizes under the same poling treatment was attributed to a greater tendency for microcracking in the large grain‐size specimens. In the absence of microcracking, as shown in small grain‐size specimens, the decrease in kp and failure of the poled specimens is attributed to slow crack growth. The optimum poling conditions for small grain‐size specimens were evaluated in terms of reducing the slow crack‐growth effect.