No abstract

No 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 CaBi 2 Nb 2 O 9 :xwt%BiFeO 3 (CBN:xwt%BFO) composites are engineered in a unique way by embedding the isolated BiFeO 3 (BFO) grains at the grain boundaries of the CaBi 2 Nb 2 O 9 (CBN) matrix. The composite with 0-3 type connectivity (CaBi 2 Nb 2 O 9 :40wt%BiFeO 3 ) exhibits a high density of 7.98 g/cm 3 , a high saturated polarization of ~19 μC/cm 2 , high resistivity of ~10 10 Ω. cm, and an enhanced piezoelectric coefficient d 33 of 29 pC/N at room temperature. Composite shows the sharp-peaked ferroelectric-paraelectric transition at high Curie temperature T C of ~881°C. Importantly, the composite maintains a very high resistivity of ~10 5 Ω.cm even at 500° C and the d 33 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.