Basic Studies on Templated Grain Growth of Relaxor Ferroelectric Crystals and Textured Ceramics

摘要

Templated grain growth (TGG) enables the relatively low cost fabrication of textured ceramics with single crystal-like properties, as well as single crystals. The resulting ceramics show texture levels up to 90%, and significant enhancements in the piezoelectric properties relative to randomly oriented ceramics with comparable densities. The piezoelectric coefficients of highly textured PMN-32.5PT ceramics were found to be (caret)1.2- 1.5 times greater than randomly-oriented samples. The unipolar strain-field measurements (pc textured sodium bismuth titanate - 5.5 mol% barium titanate rhombohedral ceramics showed 0.26% strain at 70 kV/cm, and large field piezoelectric coefficients over 500 pC/N were obtained for highly textured samples (f(caret)90%). Reasons are given for why the high field dielectric and electromechanical properties are more hysteretic than those of single crystals.