Abstract
Highly dense piezoelectric ceramics of tungsten bronze-type (Sr1.9Ca0.1)1-0.5xBaxNaNb5O15 (where x=0.1–0.8) were prepared by spark plasma sintering. The crystallographic parameters, dielectric behaviors and piezoelectric properties of the sintered ceramics were investigated, and the effects of the Ba substitution on these electrical properties were discussed. The structural analysis and the electrical property measurements indicate a morphotropic phase boundary (MPB)-like phenomenon at x=0.4–0.5. In all compositions, a diffuse phase transition and a relaxor behavior are observed. The electrical properties are found to be crystallographically dependent.