Effect of thermal energy on 90° domain switching characteristics of piezoelectric ceramic

Abstract

Domain switching characteristics of a commercial lead zirconate titanate piezoelectric (PZT) ceramic at high temperature of 100℃ were investigated using an electron backscatter diffraction (EBSD) system. The PZT ceramic consisted of a tetragonal structure with grain size of about 5μm. To analyze the domain switching characteristics, the EBSD analysis was carried out in the same region of the PZT ceramic before and after the heating process. From this analysis, it appeared that each grain is formed by three different domains with different ratio. The area ratio of the domain was altered after the heating process because of the 90° domain switching. To understand clearly the 90° domain switching characteristics, the domain modes were categorized with the angle between the poling direction and c-axis of the tetragonal structure. Although the domain mode was categorized, no clear switching pattern was clarified, i.e., domain switching occurred randomly. Such domain switching mode was attributed to the complicated thermal stress in the PZT ceramic. In order to clarify the domain switching pattern under the heating process, the switching characteristics were investigated in details, in which the grain, having different stress distribution, was selected. The grain selected was constrained in the wide area by the other grains and some region was non-constrained due to the vacancy. From this analysis, severity of domain switching depended on the stress level, e.g., the higher compressive stress, caused by the thermal expansion of the other grains, made the strong domain switching.