High-power single crystal based projectors

Significant progress has been made at integrating single crystalline relaxor ferroelectrics into many types of SONAR transducers. For high-power projectors, PMN-28PT has offered efficient, broad band-width capability. For higher duty cycles, thermal limitations are reached resulting in power and duty cycle tradeoffs. Electrical bias is also required for crystal implementation when high-power operation is needed. Continuing research in compositional tailoring has resulted in several new modified relaxor crystal systems with improved temperature stability, lower loss, and higher coercive fields. PIN-PMN-PT ternary crystals are of particular interest. This ternary system offers 25–40 °C improvement in working temperature, reduced temperature sensitivity, and approximately two times increase in coercive field without sacrifice in electromechanical coupling or piezoelectric coefficients. To demonstrate the impact of this newer ternary crystal composition on high-power transduction, planar tonpilz arrays were fabricated and tested. This presentation will highlight important material properties and compare the results of high-power measurements of single transducer elements and arrays made from PMN-28PT and PIN modified ternary crystals. Acoustic tests were conducted as a function of ambient temperature, increased drive level, and increased duty cycle operation. [Work supported by ONR.]