High frequency vibration of piezoelectric ceramic disc at the resonate point

Due to many factors affecting the frequency and different application methods, we only provide the resonance frequency of piezoelectric ceramic plate as a reference under no-load condition. However, this resonance frequency, the natural frequency of piezoelectric ceramics,which can not be used as the frequency of use, it can reflect the response time of piezoelectric ceramics.    

      
  As we all know, when working at the resonance point, the piezoelectric ceramics can achieve greater displacement at the natural frequency point.  Generally, the resonant frequency of single-layer Pzt ceramics components is used. The large resonant frequency of single-layer piezoelectric ceramic chip that the core can provide tomorrow can reach 8 MHz. Why can single-layer piezoelectric ceramic vibrate at high frequency at the resonance point, while laminated piezoelectric ceramic.    

   The single-layer piezoelectric ceramic is a kind of piezoelectric ceramic with integral structure. The high frequency vibration will not damage the piezo ceramic structure itself;     

   
    The electrostatic capacity of a single piezoceramic wafer plate is relatively small; The laminated piezoelectric ceramic is formed by the alternating bonding and co firing of the piezoelectric ceramic layer and the electrode layer in the range of 100 μ M. the long-term oscillation of the resonance point will lead to the fracture and damage of the ceramic layer; The laminated piezoelectric ceramics have a large electrostatic capacity. The periodic cycle of piezoelectric ceramics is completed by charging and discharging. Charging and discharging are used to generate force or displacement. There is no mechanical energy storage, resulting most of the energy loss and conversion to heat. The single-layer piezoelectric ceramics can be made soft or hard materials. The displacement of resonance point will change greatly with the selection of materials.     

The soft material piezoelectric ceramic has very low quality factor and high mechanical damping. The displacement amplification of resonance point is less than 10 times. The soft material piezoelectric ceramic is mainly used for stacking piezoelectric ceramic crystal, while the hard material piezoelectric ultrasonic transducer has very low mechanical damping. The quality factor is greater than 1000, and the vibration displacement is much larger than that of the soft material. In addition, the single-layer piezoelectric ceramics are using hard materials as ultrasonic applications have strong mechanical storage capacity, very low mechanical and electrical energy conversion, and the mechanical vibration energy is greatly superposed to form a larger vibration amplitude value. However, the ability of piezoelectric ceramics made of soft materials to accumulate oscillation energy at resonance point is far less than that of ultrasonic ceramics.