Piezoelectric acceleration sensors based on LGX and ReCOB crystals for application above 645ºC

In the field of aviation and aerospace engine, monitoring of the vibration of the engine in situ directly in the high temperature part is of great importance for the safe and performance of the engine. So there is demanding for sensors that can stand for high temperature of 645^oC or above temperature. Recently, the crystals of langasite and ReCOB family are found to be good candidate for this application through the study of basic properties of crystals at high temperature. But there is few reports about the acceleration sensors made of these crystals. In this work, the single crystals of La₃Ga₅SiO₁₄ (LGS), La₃Ga_5.5Ta_0.5O₁₄ (LGT), YCa₄O(BO₃)₃ (YCOB) and SmCa₄O(BO₃)₃ (SmCOB) were grown by Czochralski method respectively, and the basic properties of these crystals were characterized. The acceleration sensors with LGT as sensitive components were successfully made and characterized up to 700^oC. The results show that sensors made by these crystals can be used at the high temperature circumstance above 645^oC and under the vibration with frequency in the range of ten Hz to several thousands Hz.