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 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.

Enhanced electrical properties and conduction mechanism of A-site rare-earth Nd-substituted CaBi2Nb2O9

“…To evaluate the comprehensive performance of the Ndmodified CBN, the dielectric, piezoelectric and electrical properties of some CBN-based ceramics fabricated by conventional solid-state reaction methods reported in previous investigations are listed in table 3 [56][57][58][59][60]. It can be seen that the piezoelectric properties seem to show a negative correlation with the Curie temperature and HT electrical resistivity.…”

Realizing Enhanced Electrical Properties of CaBi2Nb2O9-Based High-Temperature Piezoceramics by Constructing a Pseudophase Boundary

“…Piezoelectric devices such as piezoelectric force transducers, accelerometers, and speed sensors are extensively applied to record the real-time mechanical parameter of aero-engines and nuclear power equipment . Taking the aero-engine, for example, piezoelectric devices are often needed to continuously monitor the operating conditions of the internal components, whose working temperatures are usually above 500 °C. In this case, the conventional PZT-based piezoelectric material is challenging to cope with the special needs of these fields because of the low T C (∼360 °C). , Therefore, developing novel piezoelectric materials that could withstand a higher temperature is urgently needed.…”