Recent advances in piezoelectric materials

Recent developments in piezoelectric materials include submicron grain size ceramics and single crystals. Pb(Zr,Ti)O 3 (PZT) ceramics with submicron grain sizes (approximately 0.5 micrometer) have been produced with properties comparable to conventional, coarse grained (approximately 3 to 5 micrometer) ceramics. The fine grain ceramics exhibit improved machinability over conventional materials. Ultrasonic transducer arrays with post widths less than 15 micrometers have been fabricated as well as thin plates with thicknesses as low as 10 micrometers. The yields and performance of such operations are expected to be much greater with fine grain ceramic than with conventional material. The single crystal piezoelectrics developed offer field induced strain an order of magnitude higher than what can be achieved in piezoelectric ceramic actuators (greater than 1%). Furthermore, the strain electric field hysteresis and dielectric losses are very low for these materials and electromechanical coupling factors (k 33 ) are greater than 90%. Applications which may benefit from the recent developments include smart materials and structures and MEMS.