Influence of crystal structure on crack propagation under cyclic electric loading in lead-zirconate-titanate

Crack propagation under cyclic electric loading was studied in two non-commercial compositions of lead-zirconate-titanate and compared to earlier results from a commercial composition. These materials were chosen to provide a well-defined variation in crystal structure, ranging from rhombohedral to tetragonal, including a composition from the morphotropic phase boundary. The results are presented in terms of crack propagation as a function of various electric load amplitudes. While the crack propagation rates were of the same order of magnitude in all three compositions, fracture occurred in an either trans- or intergranular manner with crack extension either in the form of a singular crack, a microcrack zone or with extensive secondary cracking. These differences in crack propagation are discussed in the context of different piezoelectric material properties. (c) 2008 Elsevier Ltd. All rights reserved.