Influence of Tighting Torque on the Performance of High Temperature Piezoelectric Vibration Sensor Using BTS Crystal

Contact stiffness between sensitive elements and electrodes in piezoelectric vibration sensor is one of the basic parameters, which has a direct influence on the characteristic frequency and dynamic performance of the vibration sensors. Since the contact stiffness has been generally neglected, there are few rules in designing and fabricating sensors. In order to solve this problem, a compression-mode piezoelectric vibration sensor using Ba ₂ TiSi ₂ O ₈ (BTS) single crystals was designed, assembled and tested for high temperature vibration sensing. Stiffness model of the vibration sensor was presented first, followed by BTS single crystal plates preparation, sensor assembly and experimental setup establishment. The fully packaged sensor by laser welding was characterized at temperatures ranged from room temperature to 650 °C under frequency range of 120Hz to 620Hz. Results indicated that the BTS based piezoelectric vibration sensors retained the same sensitivity at 500 °C for a dwell time of 72h, exhibiting a high stability and reliability.