Views: 3 Author: Site Editor Publish Time: 2018-10-15 Origin: Site
The temperature of the lead oxide volatilization hydrothermally synthesized PZT piezo ceramic powder is 944.71°C, and the reaction temperature between the particles is 811.26° C; the reaction temperature between the solid phase synthetic PZT powder particles is 1243.47 ° C, and the volatilization temperature of lead oxide is 1212.29°C; The lowest eutectic temperature of the PZT system is 838°C. It can be seen that reasonable process measures must be taken according to the volatilization mechanism of lead and the preparation method of PZT powder is to reduce lead volatilization and improve the performance of PZT products. Studies have shown that Zr/Ti is closely related to the performance of PZT products. Currently, for the study of PZT materials, Zr/Ti is mainly concentrated in the range of material. However, Pzt piezoelectric disks are relying solely on different Zr/Ti to improve the performance of PZT products can not meet the requirements of PZT products in the same field. It is also necessary to improve the product performance by selecting some appropriate amount of dopants on the basis of Zr/Ti. At the same time, the influence of the fluctuation of Zr/Ti on the performance stability of PZT products is reduced.
The additive can be mutually soluble in the main crystal lattice and can be precipitated in the grain boundary in the form of the second phase. When the mutual solution is dissolved, the second phase is precipitated in the grain boundary, which affects the bonding force between the grains or the grain boundary performance. The main effects of doping include formation of vacancies and inhibition of grain growth, it is formation of liquid phase and expansion of the sintering temperature piezoelectric tubular transducer. At the same time, according to the role of the dopant in the PZT piezoelectric ceramic, it can be divided into three types. acceptor doping and variable ionic is compound doping. In the doping modification study of PZT piezoelectric ceramics, La3+, Mn2+ and Nb5+ have been studied in large quantities.which studied the effect of doped Nb2O5 on the preparation of PZT65/35 material by solid phase method. It was found that the addition of niobium significantly promoted densification and inhibiting grain growth; with the increasing of niobium content and niobium content.The strengthening of the electrostatic action of the surface body makes the solubility limit in the PZT material about 7 %. When the amount is less than 7 ml%, the yttrium and the perovskite crystal lattice are completely mutually soluble. At this time, the product is completely a perovskite phase, showing the donor. when the amount is more than 7 ml%, excess ruthenium will react with lead or titanium, resulting in the production of a second phase, such as a fluorite phase, which lowers the dielectric properties and piezoelectricity.
The effects of manganese doping on the microstructure and piezoelectric properties of PZT materials were investigated. The valence state of manganese in PZT materials was determined . The results show that manganese exists mainly in Mn2+ and Mn3+ in PZT materials. In PZT ceramics. The "solubility" is about 1.5 mol%. When the manganese content is less than 0.5 mol%, Mn will preferentially enter the (Zr, Ti) position in the crystal lattice by means of Mn2+ and Mn3+. The manganese doping material also exhibits in this concentration range. Piezoelectric activity of "soft" and "hard" materials have different types of dopants, the research focus is on improving the properties of the product by finding the proper amount of addition to make it completely soluble in the PZT polarized piezo transducers. In addition, the current doping of modification research is doping objects mainly focus on the solid phase method to prepare PZT materials, and doping with oxide solid phase shape, it is difficult to ensure the uniformity of components and accurate stoichiometry, how to achieve phase doping will be one of the future research directions of PZT piezoelectric ceramics.
