Views: 17 Author: Site Editor Publish Time: 2018-09-16 Origin: Site
There are main structure of piezoelectric ceramics .Piezoelectric ceramics are numerous and different type, but from the perspective of crystal structure, there are mainly three types of piezoelectric ceramics, which are perovskite structure, tungsten bronze structure and bismuth-containing layer structure.
1. Perovskite structure
Most useful PZT materials piezo ceramics are perovskite structures with the general formula ABO3, and the valence of AB can be A2+B4+ or A1+B5+. Figure is a schematic diagram of the structure of the ABO3 perovskite. The simple cubic perovskite structure is composed of a series of octahedrons with common apex angles. The center of the oxygen octahedron is a high price radius B-site ion, such as Ti, Sn. , Zr, Nb, Ta, W, etc., and in the oxygen octahedron, is a large radius, low electricity price, coordination number 12 A-position ions, such as Na, K, Rb, Ca, Sr, Ba, Pb, etc.
2. Tungsten bronze structure
Some of the oxygen octahedral ferroelectrics are present in a tungsten bronze structure, and are named for their similar structure to the tetragonal tungsten bronzes KxWO3 and NaxWO3. The basic feature of this structure is that a tetragonal unit cell contains 10 BO6 octahedrons, such as PbNb2O6, NaSr2Nb5O15, and so on. It is similar to the perovskite structure, this type of ferroelectric also has an oxygen octahedral network structure, but piezoceramic material piezoelectric sensor is more complex than a simple perovskite structure. The oxygen octahedrons are stacked in a stack along the quadrupole in the form of a common apex, and the stacks are connected in a common point. Unlike the perovskite structure, these stacks are inconsistent in the plane perpendicular to the quadruple axis, and different voids are formed between the different stacks of oxygen octahedrons.
3. Layered structure containing enamel
