Application of Piezoelectric Ceramics in Mechanical Systems
Publish Time: 2018-11-30 Origin: Site
Since the curie brothers discovered the piezoelectric effect of tourmaline in 1880, piezoelectric science has officially entered the stage of human science and technology civilization. Early theoretical research was mainly done by the curie brothers later. In 1881, the curie brothers verified the inverse piezoelectric effect of theα-quartz crystal through experiments, that is, giving an electric field to the quartz crystal, and obtaining slight strain and stress feedback. And the positive and negative piezoelectric coefficients of the piezoelectric transducer ultrasound were calculated through experiments. After 13 years, Voigt proposed that the medium has a piezoelectricity premise that it has an asymmetric center, and only 20 of all 32 point groups have this characteristic. Quartz is a typical representative of it. In the years the theory was put forward, quartz crystals remain the experimental stage. Further application and manufacturing has been slow. War is the biggest driving force for the development of science and technology until World War I, Curie's heir, Lanngevin, used quartz to create underwater ultrasonic detectors for the military purpose of detecting submarines, which pushed piezoelectrics into practical applications. In the World War II, Roberts of the United States applied a high voltage to the BaTiO3 ceramics for polarization treatment to obtain the piezoelectricity of the piezoelectric ceramics. Immediately after the United States, Japan, and the Soviet Union began researching on piezoelectric ceramics, they all achieved good results.From then until the mid-1950s, various piezoelectric devices such as high-frequency transducers, ultrasonic transducers, pressure sensors, filters, resonators, etc. made of BaTiO3 piezoelectric ceramics have sprung up, making the application of piezoelectric ceramics . In 1955, after long-term research and experiments, B. Jaffe et al. finally found PZT piezoelectric ceramics are superior in piezoelectric crystal cost to BaTiO3. Its superior performance makes it possible to apply piezoelectric ceramics to more electronic devices. SAW devices are using surface acoustic wave (SAW) filters, delay lines, and oscillators have also been used in subsequent studies. Since then, piezoelectric ceramics have undergone reform and innovation, and new varieties have emerged.
Piezoelectrics is a discipline of partial experimentation, and the development of hard material piezoelectric ceramics components is closely related to the composition and structure of piezoelectric ceramics. The composition and structure determines the performance of the component. In recent years, research in the scientific community has shifted to two extremes: very small or extremely large. That is, to study topics at the microscopic scale, or to discuss problems within the universe. In this situation, precision instruments have been extensively developed and used. Due to the subtlety of the piezoelectric effect of piezoelectric ceramics, its application prospects in precision instruments are very broad. There are many examples of instruments in precision testing equipment and precision power equipment. This article aims to give readers a preliminary understanding of the application performance of Pzt4 piezoelectric ceramics by enumerating the existing application, and to analyze the advantages and disadvantages of piezoelectric ceramics in the application of precision instruments, and to try to propose some applications for piezoelectric ceramics.
The application of mechanical forces to certain dielectrics causes their internal positive and negative charge centers of Pzt ceramic disc to be relatively displaced, resulting in polarization, resulting in the appearance of oppositely bound charges in the ends of the dielectric. In a certain range of stress, the mechanical force is linearly reversible with the charge. This phenomenon is called piezoelectric effect or positive piezoelectric effect. On the other hand, if a medium is having a piezoelectric effect is placed in an external electric field, the center of the positive and negative charges inside the medium is displaced due to the action of the electric field, and this displacement causes the medium to deform. In a certain range of electric field strength, the electric field strength has a linear reversible relationship with the deformation. This effect is called the inverse piezoelectric effect.
The piezoelectric material is a piezoelectric ceramic by a mixture of ingredients, high-temperature sintering, and irregular assembly of solid particles after solid phase reaction between the particles. The spontaneous polarization of the polarized piezoelectric ceramic is randomly oriented, so there is no piezoelectricity. The spontaneous polarization domains existing in the high-voltage DC electric field are rearranged according to the preferred orientation of the external electric field. After the external electric field is removed, the ceramic body still retains a certain total residual polarization, so that the piezoceramic cylinder tube has piezoelectricity. Curie temperature ferroelectric (or antiferroelectric) ceramics have ferroelectric (antiferroelectric) properties only in a certain temperature range, and they have a critical temperature Tc. When the temperature is higher than Tc, the ferroelectric (or antiferroelectric) phase changes to a paraelectric phase, and the spontaneous polarization disappears. This critical temperature TC is called the Curie temperature of a ferroelectric (or antiferroelectric) ceramic.