Fabrication of BiScO 3 –PbTiO 3 /epoxy 1–3 piezoelectric composites for high‐temperature transducer applications

1–3 piezoelectric composites are widely used in piezoelectric ultrasonic transducers due to their high thickness electromechanical coupling factor. However, the applications of the composites in high‐temperature fields are limited by the low heat resistance of both the piezoelectric and polymer phases. To tackle this, we designed and fabricated the BiScO 3 –PbTiO 3 /epoxy high‐temperature 1–3 piezoelectric composites. These composites exhibit a high thickness electromechanical coupling factor k t of 63%, a large piezoelectric coefficient d 33 of 470 pC/N, and a pure thickness vibration mode. Furthermore, we fabricated a high‐temperature transducer based on the BiScO 3 –PbTiO 3 /epoxy 1–3 composites. The bandwidths of the composites measured in water and silicone oil (30% and 23%, respectively) are approximately 1.65 times greater than those of monolithic piezoelectric ceramics (18% and 14%, respectively). The bandwidth of the transducer can be increased to 78% by adding a porous alumina backing layer, with the working temperature reaching up to 300°C. The results indicate that the BS–PT/epoxy 1–3 composite is a potential candidate for high‐temperature transducer applications.