According to different bases, the current classification of various non-lead piezoelectric ferroelectric ceramic systems is slightly different. The various classifications are summarized as follows. The name of the perovskite structure comes from the structure of the mineral CaTiO3, whose general chemical formula is ABO3. Many important piezoelectric ceramics (including lead-based and non-lead-based ceramics) exist in the perovskite structure.
Mainly include barium titanate (BaTiO3)-based (BT-based) lead-free piezoelectric ceramics, sodium bismuth titanate [(Bi0. 5Na0. 5) TiO3]-based (BNT-based) lead-free piezoelectric ceramics and alkali metal potassium sodium niobate [(K, Na) NbO3]-based (KNN-based) lead-free piezoelectric ceramics. This type of crystal structure is similar to the perovskite structure (so it is sometimes not listed separately when dividing the system).
Mainly include lead-free piezoelectric ceramics represented by strontium barium niobate (Sr1-xBaxNb2O6) series and sodium barium niobate (NaBa2Nb5O15) series. This type of piezoelectric ceramic is a compound with a layered structure, which is composed of bismuth layered structure compound layers and perovskite structure lattice layers interspersed and overlapped.
Mainly include bismuth layered structure lead-free piezoelectric ceramics represented by bismuth titanate (Bi4Ti3O12), calcium bismuth titanate (CaBi4Ti4O15) and strontium bismuth titanate (SrBi4Ti4O15).