What are the common piezoelectric materials?

The first category is inorganic piezoelectric materials, which are divided into piezoelectric crystals and piezoelectric ceramics. Piezoelectric crystals generally refer to piezoelectric single crystals. Piezoelectric ceramics generally refer to piezoelectric polycrystals.

Piezoelectric ceramics are polycrystals made of raw materials with basic components, which are mixed, molded and sintered at high temperature, and the fine grains obtained by solid-state reaction and sintering between powder particles are irregularly assembled. Piezoelectric ceramics are actually ferroelectric ceramics. There are ferroelectric domains in the ceramic grains, which are composed of 180 domains with anti-parallel spontaneous polarization directions and 90 domains with vertical spontaneous polarization directions. These areas are artificially polarized.