AlN Ultrasound Sensor for Photoacoustic Lamb Wave Detection in a High-Temperature Environment

Abstract

In this paper, we present an ultrasound nondestructive testing (NDT) method for high-temperature (HT) applications using laser-generated Lamb waves and aluminum nitride (AlN) sensors. Lamb waves were introduced to a stainless steel plate by the Nd:YAG pulsed laser at one point and detected by an AlN receiver at a distant position. The fundamental symmetric ( ) and antisymmetric ( ) Lamb waves generated by the pulsed laser were successfully detected by the AlN sensor. This detection was done on a stainless steel plate at temperatures ranging from room temperature to about 800 °C, with a signal-to-noise ratio of higher than 20 dB. Based on the time-of-flights analysis, the ability of this NDT method to localize the defect at an HT (~800 °C) has been demonstrated.

Shear Horizontal Guided Wave Sensors Based on CTGS Piezoelectric Crystal for High‐Temperature Structural Health Monitoring

“…Design of Optimum Piezoelectric Crystal Cut: To meet the requirements for ultrasound-guided wave sensing under high temperature conditions, Low usage temperature, low sensitivity [ 22,23] 4 4.5 (d 11 ) 9 7 0 ≥600 Low sensitivity [ 24] AlN −1.9 (d 31 ) 2000 ≈800 Medium sensitivity [ 4 ] YCOB 7.9 (d 26 ) 1500 ≈1000 Medium sensitivity [ 35] CTGS 14.8 (d 25 ) 1400 ≥600 / crystal cut possessing high piezoelectric coefficient while minimizing piezoelectric crosstalk was designed. Experimental impedance and phase spectra of optimum crystal cut were discussed.…”

“…To date, different sensors have been developed for SHM at elevated temperatures, such as acoustic emission sensors (AE), laser DOI: 10.1002/aelm.202300851 ultrasonic sensors, and so on. [1][2][3][4] The AE technology represents a passive detection method capable of identifying damage in a variety of structures and predicting its progression. It is less susceptible to interference from vibrations and noise.…”

“…But the transmitting sensitivity of AlN sensors was relatively low. [ 4 ] In addition, the YCOB crystal grown by the Czchoralski pulling method possesses high electrical resistivity. And the piezoelectric coefficient d 26 of YCOB is ≈7.9 pC N −1 .…”

Surface temperature condition monitoring methods for aerospace turbomachinery: exploring the use of ultrasonic guided waves

“…Aluminium Nitride (AlN) also exhibits a number of very promising properties necessary for high temperature sensing such as high electrical resistivity, temperature independence of electromechanical properties, and high thermal resistivity of the elastic, dielectric, and piezoelectric properties [138]. The use of an AlN sensor up to 800 • C has been demonstrated for detection of laser generated Lamb waves in thin steel plates by Kim [139]. Unfortunately high-quality AlN single crystals are difficult to grow, showing a wide range of resistivity that greatly affects their suitability as ultrasound transducers [140].…”

Laser ultrasonic defect localization using an omni-arrayed candle soot nanoparticle patch

“…For example, in high-temperature applications, the piezoelectric ultrasound transmitters are limited in wave generation with relatively low amplitude, largely because of the low piezoelectric coefficients of high-temperature piezoelectric materials compared with their mainstream lead-based piezoelectric materials. [3][4][5][6] For this reason, noncontact methods have been researched, including EMAT (Electro Magnetic Acoustic Transducer), 7) air-coupled ultrasound 8) and laser-ultrasonics. [9][10][11] Among these methods, the laser-ultrasonic method has established a large progressive improvement taking the advantage of easy laser beam patterning with proper optical elements, such as a slit mask or cylindrical lens, and arrayed patch.…”