Piezoelectric transducer materials

The transducer usually has a composite structure, in which the piezoelectric material is the functional material in the device. Piezoelectricity exists in many different materials. However, only a few were found to be suitable for practical applications. The common piezoelectric materials can be generally divided into single crystals, piezo ceramics, piezo polymers and composites. The polycrystalline piezoelectric ceramics have been found effective in a wide range of usage and can be further divided into perovskite and nonperovskite structured ceramics. The nonperovskite structured materials mainly include potassium tungsten bronze structured PbNb2O6, pyrochlore structured Cd2Nb2O7, and bismuth layer structured Bi4Ti3O12. The perovskite structured materials that have been developed and investigated are mainly BaTiO3, PbTiO3, PbZrO3, Pb(Zr,Ti)O3 (PZT), Pb[(Sc,Nb)Ti]O3 (PSN-PT). Among so many types of piezoelectric ceramics, modified PZT based solid solutions are basically the dominant materials as they are ideal for most of electromechanical transducers, such as phonograph pickups, air transducers, instrument transducers, underwater sound, delay line transducers, wave filters and high voltage sources, due to their ability to generate high force, large displacements, high conversion efficiency and design versatility.