TECHNIQUES FOR THE GENERATION OF ULTRASOUND FOR EXTENDED PERIODS AT HIGH-TEMPERATURES

Four transducer materials and various types of adhesive bond are considered for the generation of ultrasound at high temperatures. Measurements of insertion loss, transducer coupling factor and capacitance indicated that the most successful transducer-bond combinations were PZT-5A with a solder bond for use up to 250°C, and lithium niobate with either a ceramic or gold-indium bond for use up to 400°C. These three combinations all proved relatively stable for periods in excess of 400 days at high temperatures. © 1979.