High temperature sensing

High temperature sensors are required for intelligent aerospace propulsion system design and operation, and for enhancement of system maintenance and safety. High temperature piezoelectric sensors are of particular interest because of their simple structures, fast response time, and easy integration features. However, existing piezoelectric sensors operates at temperatures below 1000 °C because of the lack of high temperature piezoelectric materials. Piezoelectric single crystal YCOB is known for its stable piezoelectric properties at high temperature (~1500 °C). In this research, a shear- mode piezoelectric accelerometer using YCOB without thin film electrodes was designed, fabricated and successfully tested, for the first time, for vibration sensing applications at temperatures ranging from room temperature to 1250 °C.

High temperature test setup (temperature up to 1300 °C)

Acoustic emission (AE) sensing is a rapidlly growing method for testing a braod spectrum of wear and fatigue in mechanical, aerospace, and civil structures. YCOB was used to fabricate an AE sensor for high tempearture applciations. During Hsu–Nielsen tests with a steel bar, this YCOB acoustic sensor showed the ability to detect zero-order symmetric and antisymmetric modes of lamb wave at 30 and 120 kHz, respectively, as well as distinguish a first-order antisymmetric mode at 240 kHz at elevated temperatures up to 1000°C. The frequency characteristics of the signal were verified using a finite-element model and wavelet transformation analysis.

AE-1

Joe-UFFC-2014

Calculated dispersion curve for a single-layer 309 stainless steel substrate using a stationary AE excitation source with a distance of 200 mm. Dispersion curve overlaid onto wavelet transform of experimental data from the Hsu–Nielsen test for comparison of time of arrival and frequency characteristics.

References:

Kim, T., J. Kim, R. Dalmau, R. Schlesser, E. Preble, X. Jiang, “High Temperature Electromechanical Characterization of AlN Single Crystals“, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 62(10), 1880-1887, (2015).
Johnson, J., K. Kim, S. Zhang, D. Wu, X. Jiang, “High-temperature acoustic emission sensing tests using a yttrium calcium oxyborate sensor“,Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on, 61(5), 805-14 (2014).
Kim, K., S. Zhang, G. Salazar, X.N. Jiang, “Design, fabrication and characterization of high temperature piezoelectric vibration sensor using YCOB crystals”, Sensors and Actuators: A Physical, 178, pp. 40–48 (2012).
Kim, K., S. Zhang, W. Huang, F. Yu, X. Jiang, “YCa4O(BO3)3 (YCOB) high temperature vibration sensor“, Journal of Applied Physics, 109(12), 126103–3 (2011).