Study of ultra-micro PZT piezoelectric ceramic powder

The polarized PZT piezo ceramic becomes an ordered arrangement due to the polarization electric field forcing the disordered 90°domain and 180°domain steering in the unit cell, and the spontaneous polarization axis in the unit cell is longer than the non-spontaneous polarization axis. When the 90°domain is turned, strain is generated and a large internal stress is formed. After the external electric field is removed, the internal stress causes the internal force of the unit cell to be in an unbalanced state and store more internal energy, piezo ceramic tubular transducer leads to the disordered arrangement of the 90°.new domain before the polarization is reversed. Gradually releasing internal stress. Therefore, the remnant polarization is the root of the old mechanism with these 90°disorder.

The aging law generally includes three kinds of linear, non-linear and asymptotic straight. Factors are affecting the aging of piezoelectric tube transducer products including extrinsic and intrinsic factors. External factors are related to the environment in which they are used. Such as temperature, temperature, etc.; intrinsic factors are closely related to domain structure and domain motion, because the polarization inversion process under high electric field is uniform through the structure of the domain wall, such as the increasing of grain size, the grain boundary volume fraction is reduced, The coupling between the grain boundary and the domain wall is reduced, making the reorientation of the domain more difficult, the serious thickness and the property of the domain wall movement, and thus the remnant polarization and dielectric constant increase with the increasing of the grain size, the coercive field strength decreases.

The thickness and properties of the grain boundaries also have an effect on the domain structure. The extremely thin grain boundaries develop the domains across the grain boundaries and improving the piezoelectricity. In addition, doping also contributes to the improvement of the anti-aging property of the product. This is because the spontaneous polarization domain is closely related to the unit cell symmetry. After adding an appropriate amount of dopant, the unit cell structure is distorted, which is more conducive to the reorientation of the domain wall. . The domain wall is easily moved, the intra-domain stress is easily released, and the aging resistance is good. The microstructure after sintering is closely related to the PZT powder activity and the densification sintering process. 

The PZT piezoelectric cylinder tubes transducer prepared by the wet chemical method generally has better powder activity than the solid phase method, low sintering temperature, low lead volatilization, and sintered products. The grain size is finer, the microstructure is more uniform, the density is higher, and the aging resistance is better than the solid phase method. PZT piezoelectric ceramics has been researched for nearly 50 years. It has been widely used in electronics, radar, micro-displacement control, aerospace technology and computer technology. From the form reasons and solutions of the above problems, the search for the synthesis of high-activity PZT powder may be the fundamental solution to the above problems.To this end, it is necessary to study various new synthetic methods of ultrafine PZT powders, and further study the synthesis mechanism and process amplification conditions of various wet chemical methods, so as to achieve the lowest cost, simple process and equipment and large-scale synthesis performance. The superior performance of the excellent PZT piezoelectric ceramic material is more widely used.