Disposable PVDF ultrasonic transducers for nondestructive testing applications

The performance of commercial PVDF films and ultrasonic contact transducers, used in nondestructive testing (NDT) applications, was studied as a function of temperature. The PVDF films were evaluated for their temperature dependent material properties of interest for ultrasonic transducer performance. Commercial disposable PVDF transducers were then coupled to test panels and their ultrasonic insertion loss/sensitivity and frequency bandwidth measured as a function of temperature in both the pulse-echo and pitch-catch modes. The temperature dependence of the transducers´ performance is reported for the -40° to 80°C range. Each of the contact transducers was also mounted on a holder, which permitted use as an immersion transducer, and its pulse-echo acoustic performance was measured in water. The results varied widely, from excessive ringing and poor performance, to very broadband short pulse-width (1.2λ) performance. This paper summarizes the quantitative materials characterization and ultrasonic tests for the commercial PVDF film and transducers which were tested