Lead-free piezoelectric ceramics PZT
Mainly leaded traditional piezoelectric ceramic lead zirconate titanate (PZT) system based materials, its main ingredient is lead oxide (more than 60 to 70 percent). Lead oxide is a volatile toxic substances in the production, use and handling of the waste after the procedure will cause harm to humans and the environment. Also cause volatilization of PbO in the stoichiometric ratio deviates from the ceramic, so that the product consistency and repeatability of reducing, sintering to be sealed, so that cost increases.
Therefore, the research and development of high-performance lead-free piezoelectric ceramics has a very important scientific significance and urgency of market demand, has become a hot research.
Depending on the basis of various current lead-based piezoelectric ceramics system ferroelectric division slightly different. Comprehensive various categories are summarized as follows.
Perovskite structure
The name comes from the structure of the perovskite structure of the mineral CaTiO3, the chemical formula ABO3, many important piezoelectric ceramic (including lead-based and lead-in ceramic) are based on the existence of the perovskite structure.
Including barium titanate (BaTiO3) base (BT-based) lead-free piezoelectric ceramics, sodium bismuth titanate [(Bi0. 5Na0. 5) TiO3] group (BNT base) lead-free piezoelectric ceramics and alkali metal potassium sodium niobate [(K, Na) NbO3] group (KNN base) lead-free piezoelectric ceramics.
Tungsten bronze structure
Such perovskite crystal structure similar to (it sometimes does when the system is divided listed separately).
Mainly including strontium barium niobate (Sr1-xBaxNb2O6) system and barium sodium niobate (NaBa2Nb5O15) for lead-free piezoelectric ceramics department representatives.
Bismuth layered structure
Such compounds having a layered structure of a piezoelectric ceramic, bismuth layer-structured compound by the layer and a layer of a perovskite crystal structure formed by overlapping interspersed.
Including bismuth titanate (Bi4Ti3O12), bismuth titanate, calcium (CaBi4Ti4O15) and strontium bismuth titanate (SrBi4Ti4O15), represented by lead-free piezoelectric bismuth layer structure
