Preparation, Structure, and Electrical Properties of Cobalt-Modified Bi(Sc3/4In1/4)O3-PbTiO3-Pb(Mg1/3Nb2/3)O3 High-Temperature Piezoelectric Ceramics.

ABSTRACT

Cobalt-modified 0.40Bi(Sc3/4In1/4)O3-0.58PbTiO3-0.02Pb(Mg1/3Nb2/3)O3 ceramics (abbreviated as BSI-PT-PMN-xCo) were produced by conventional two-step solid-state processing. The phase structure, micro structure morphology, and electrical properties of BSI-PT-PMN-xCo were systematically studied. The introduction of Co ions exerted a significant influence on the structure and electrical properties. The experiment results demonstrated that Co ions entered the B-sites of the lattice, resulting in slight lattice distortion and a smaller lattice constant. The average grain size increased from ~1.94 µm to ~2.68 µm with the increasing Co content. The optimized comprehensive electrical properties were obtained with proper Co-modified content 0.2 wt.%. The Curie temperature (Tc) was 412 °C, the piezoelectric constant (d33) was 370 pC/N, the remnant polarization (Pr) was 29.2 µC/cm2, the relatively dielectric constant (εr) was 1450, the planar electromechanical coupling coefficient (kp) was 46.5, and the dielectric loss (tanδ) was 0.051. Together with the enhanced DC resistivity of 109 Ω cm under 300 °C and good thermal stability, BSI-PT-PMN-0.2Co ceramic is a promising candidate material for high-temperature piezoelectric applications.