ASA 126th Meeting Denver 1993 October 4-8

2pEA7. Electromechanical properties of new electrostrictive materials for underwater acoustical applications.

Kurt M. Rittenmyer Robert Y. Ting

U.S. Naval Res. Lab., Underwater Sound Reference Detachment, P. O. Box 568337, Orlando, FL 32856-8337

Electrostrictive ceramics are known to be capable of generating strains that far exceed those of conventional piezoelectric lead--zirconate--titanate (PZT) ceramics. Several lead--magnesium--niobate (PMN) compositions developed earlier were useful only at higher temperatures than those of interest to the sonar community. A new barium-modified PMN--PT ceramic is described. This material can operate at lower temperatures and has very low losses, making it a prime candidate for high-power sonar transducer applications. Another family of electrostrictive materials capable of generating large strains is lanthanum-modified PZT (or PLZT). These materials exhibit strains up to 0.1% along with extremely high dielectric strength, but their hysteresis losses are higher than those of PMN or PMN--PT ceramics. Since the maximum possible strain output is usually the important parameter in actuator applications, the PLZT family may have potential for new actuator designs. Strain measurements for these new electrostrictive ceramics at high electric fields but different frequency ranges are presented. [Work supported by ONR.]