Comparison of the performance of pmn-pt single-crystal and ceramic composite arrays for NDE applications

Ultrasonic array technology is used in many imaging applications across a wide range of industrial sectors. Perovskite single-crystal materials such as pzn-pt and pmn-pt can be used to manufacture arrays with much increased sensitivity and bandwidth, compared to conventional piezoelectric ceramic designs. One way to take advantage of these new active materials is to incorporate the single-crystal material as the active piezoelectric elements, embedded within a passive polymeric material, in a piezoelectric composite structure. This paper describes a theoretical and experimental investigation into the performance of wideband 1-3 composite arrays utilising pzt5h ceramic and pmn-pt single-crystal as the active materials. Six-element prototype arrays were manufactured with a centre frequency of approximately 2.25 MHz. The comparison of the single-crystal and pzt5h devices is based on laser vibrometer surface displacement cross-talk measurements and electrical impedance measurements as well as transmit and receive measurements in water. The measured electrical impedance and mechanical cross-talk from the manufactured arrays correlates well with that predicted using the FE software package PZFlex. Moreover, the design techniques obtained from PZFlex, are shown to produce arrays with low cross-talk. Overall, the single-crystal device shows considerably improved performance over the pzt5h device as demonstrated by its higher bandwidth and superior pulse-echo performance