Stable piezoelectric response of 0-3 type CaBi2Nb2O9:xwt%BiFeO3 composites for high-temperature piezoelectric applications

Abstract

Depolarization in the ceramic materials has remained the longstanding obstacle for the materials to be utilized in high-temperature piezoelectric devices. Herein, a strategy to defer thermal depolarization is employed. To acquire the best merits of two different materials, 0–3 type CaBi2Nb2O9:xwt%BiFeO3 (CBN:xwt%BFO) composites are engineered in a unique way by embedding the isolated BiFeO3 (BFO) grains at the grain boundaries of the CaBi2Nb2O9 (CBN) matrix. The composite with 0–3 type connectivity (CaBi2Nb2O9:40wt%BiFeO3) exhibits a high density of 7.98 g/cm3, a high saturated polarization of ~19 μC/cm2, high resistivity of ~1010 Ω.cm, and an enhanced piezoelectric coefficient d33 of 29 pC/N at room temperature. Composite shows the sharp-peaked ferroelectric–paraelectric transition at high Curie temperature TC of ~881°C. Importantly, the composite maintains a very high resistivity of ~105 Ω.cm even at 500°C and the d33 of 24 pC/N after annealing at 700°C. Moreover, the poled composite has displayed strong radial and thickness dielectric resonances at 20–700°C. Concluding the results, the CBN:40 wt%BFO composite with 0–3 type connectivity shows the stable high-temperature piezoelectric response much better than either CBN or BFO and is the worthier candidate to be utilized in high-temperature piezoelectric devices.

Keywords

• 0-3 type composites
• cabi2nb2o9
• bifeo3
• high-temperature piezoelectric