Certain materials produce electric charges on their surfaces because of mechanical stress. The induced charges are proportional to the mechanical stress. This is called the direct piezoelectric effect. This chapter describes the piezoelectric materials that are used and various potential applications of piezoelectric materials. There are five important figures of merit in piezoelectrics: the piezoelectric strain constant d, the piezoelectric voltage constant g, the electromechanical coupling factor k, the mechanical quality factor, and the acoustic impedance Z. Ultrasonic transducers convert electrical energy into mechanical form when generating an acoustic pulse and convert mechanical energy into an electrical signal when detecting its echo. The various types of transducers used in ultrasonic imaging are described. The chapter reviews the developments of piezoelectric and related ceramic actuators with particular focus on the improvement of actuator materials, device designs, and applications of the actuators.
All Science Journal Classification (ASJC) codes
- Materials Science(all)