PZT-based leaded piezoelectric ceramics

                            PZT-based leaded piezoelectric ceramics

Although PZT-based leaded piezoelectric ceramics are dominant in piezoelectric applications. However, PZT-based piezoelectric ceramics are PZT materials that are harmful to the human body and the environment. Among them, toxic PbO acoustic piezoelectric tube is easily volatilized during processing and sintering, causing harm to the human body and the environment. Therefore, the search for a piezoelectric ceramic material that is comparable to that of PZT ceramics and has no lead piezoelectric radial tubehas become an urgent need in the field of electronic materials. At present, the research focuses at home and abroad mainly focus on two major categories: (Bi2O2) piezoelectric ceramics and lead-free piezoelectric ceramics with perovskite structure. Bilayered (BLSF) piezoelectric ceramics are the perovskite and (Bi2O2) layers are alternately arranged alternately, and their special layered structure piezoelectric tube actuator determines the following characteristics: low dielectric constant, high curie temperature, high electromechanical coupling coefficient, obvious anisotropy, high resistivity, low aging rate, large dielectric breakdown strength, low sintering temperature, etc. These characteristics determine that the piezoelectric ring transduceris particularly suitable for high temperature and high frequency applications, thus solving the problem of unstable PZT piezoelectric ceramics under high power resonance. However, the layered piezoelectric ceramics have their own disadvantages: one is that the coercive field (Ec) of piezoelectric compression sensor is too high, which is not conducive to polarization; the other is that the piezoelectric activity is low and the resistivity is low. In order to overcome these two defects, high-temperature polarization is mainly used because the coercive field decreases with increasing temperature; doping modification. . At present, the research in this area is based on PZT. Pz24 manufactured by Ferro Perm of Denmark has been successfully applied to high-power transducers. Another bolt-clamped ultrasonic transducer is the APC-841 developed by American piezo ceramic which can produce a piezoelectric transformer with output power above 30 W. For multilayer chip devices, we hope that piezoelectric ceramics have a high relative permittivity (ε) at low temperature sintering and a low dielectric loss tanδ.