High-temperature (>500^{/spl deg} C) ultrasonic transducers: an experimental comparison among three candidate piezoelectric materials

Abstract

High-temperature piezoelectric crystals, including YCa4O(BO3)3, LiNbO3, and AlN, have been studied for use in ultrasonic transducers under continuous operation for 55 h at 550°C. Additionally, thermal ratcheting tests were performed on the transducers by subjecting the crystals to heat treatments followed by ultrasonic performance testing at room temperature and 500°C. The changes resulting from the heat treatments were less than the statistical spread obtained in repeated experiments and were thus considered negligible. Finally, in situ measurements of the pulse-echo response of YCa4O(BO3)3 were performed at temperatures up to 950°C for the first time, showing stable characteristics up to these high temperatures.

High-Temperature Piezoelectric Sensing

“…The use of protective coating on the sensor device is one option; (5) backing material for HTUT: backing material is a crucial problem for high-temperature ultrasound transducers due to noises caused by imperfect damping in backing materials at HT. Recent work reveals that carbon-carbon material shows good performance as a backing material at high-temperatures (>500 °C) for long-term use (>55 h) [85]. …”

“…Recently, Parks et al have studied three different high-temperature piezoelectric materials including YCa 4 O(BO 3 ) 3 , LiNbO 3 , and AlN for HT ultrasound transducer applications [85]. Figure 14 shows a photograph of the ultrasound transducer and fixture assembly.…”

“…Waveforms obtained from in situ test at temperatures up to 950 °C for the YCOB transducer [85] (copyright 2013 by the IEEE).…”

Development of high temperature capable piezoelectric sensors

“…The results of the high temperature endurance testing performed on piezoelectric materials aluminum nitride and bismuth titanate showed that their performance at elevated temperatures was comparable (and even better in the case of aluminum nitride) to their performance at room temperature [9,10]. Aluminum nitride displayed an 11% increase in performance over the course of 35 days in temperatures reaching over 550 °C (556 °C ) and within an average temperature environment of approximately 441 °C .…”

High-temperature acoustic emission sensing tests using a Yttrium calcium oxyborate sensor

“…However, the usage temperature ranges of piezoelectric materials are generally limited by their phase-transition temperature, melting point, or [24]. In addition, ycoB was tested in comparison with linbo 3 and aln for ultrasonic detection capabilities at high temperatures, and showed little piezoelectric degradation when exposed to 1000°c for 48 h, as well as 550°c for 55 h [25]. This is a promising sign for the capabilities of ycoB as an acoustic emission sensor material.…”