Microstructure and electrical properties of Nb and Mn co-doped CaBi4Ti4O15 high temperature piezoceramics obtained by two-step sintering

Bismuth layer structural ceramics with a composition of CaBi4Ti3.95Nb0.05O15+ 0.2 wt% MnO2 (CBTN-Mn) were prepared by a two-step sintering (TSS) approach. The effect of sintering process on the microstructure and its relationship with the electrical properties of the CBTN-Mn ceramics was investigated. A dense microstructure with small and homogeneous grains was obtained under an optimized two-step sintering condition, leading to a strongly enhanced piezoelectric constant (d(33)=27 pC/N). In addition, this ceramic also possesses high Curie temperature (T-c=790 degrees C), low dielectric loss (tan delta=0.2%) and high dc resistivity (rho =5.5 x 10(6) Omega cm at 500 degrees C), indicating its potential for high temperature piezoelectric sensing applications. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.