High-temperature acoustic emission tests using lithium niobate piezocomposite transducers

High-temperature-resistant piezoelectric sensors have been used as acoustic emission sensors over a temperature range from room temperature up to 400C. The sensors were made from lithium niobate 1-3 piezocomposites, using the dice and fill method, with high-temperature-resistant cement as the passive material. Good results in detecting simulated acoustic emission signals were obtained at high temperatures, with little change from the same measurements at room temperature. Of the devices tested, a 4 mm-thick piezocomposite with 45% volume fraction of y/36-cut lithium niobate gave the best results. In addition, the possibility to use these devices to locate an acoustic emission source was verified.