High temperature piezoelectric ultrasonic transducers: Materials, design, and applications

Since the advent of ultrasonic testing, piezoelectric ultrasonic transducers have been widely applied in nonintrusive inspection across aerospace, nuclear energy, and petrochemical industries, owing to their compact structure, low cost, and broad applicability. However, as service temperatures increase, issues such as the degradation of piezoelectric material properties and mechanical failure of transducer components become increasingly pronounced, highlighting the need for further optimization to enhance transducer performance under high-temperature conditions. This paper reviews the recent research progress on high-temperature piezoelectric ultrasonic transducers (HTPUTs) from the perspectives of materials, structures, and applications. Specifically, commonly used piezoelectric material systems for high-temperature environments and their performance characteristics are systematically summarized, with particular emphasis on degradation mechanisms at elevated temperatures. Design optimization strategies for transducers operating under high-temperature conditions are discussed in detail, including the selection of matching layers and backing materials, acoustic coupling optimization, and the development of novel structural configurations. Representative applications of HTPUTs in the energy and manufacturing sectors are also highlighted, together with the key challenges encountered. Finally, future development directions for HTPUT research are outlined.