A high temperature and broadband immersion 1-3 piezo-composite transducer for accurate inspection in harsh environments

A high temperature immersion 1-3 piezo-composite transducer has been developed to demonstrate performance in both bandwidth and sensitivity a compared to one constructed using a solid ceramic. One notable benefit for high temperature applications using the 1-3 composite is a large reduction of principal thermal stress in the transducer due to the compliancy of the polymer phase. Preliminary results of thermal analysis for the transducer over a temperature range from 20 /spl deg/C to 180 /spl deg/C reveal that the 1-3 composite construction decreases the principal thermal stress in the ceramic phase by more than 70%. This reduction allows the transducer to be operated in an extended temperature range where excessive thermal stress of a solid ceramic would cause failure of the transducer. No performance degradation was observed from the transducer after several thermal cycles over a 100 /spl deg/C temperature span. Waveform and spectrum of the transducer measured in a 125/spl deg/C canola oil bath are presented.