Application of Laser-Generated Ultrasound for Evaluation of Thickness Reduction in Carbon Steel Pipes

Park, Jong Ho; Lee, Joon Hyun; Seo, Gyeong Chul; Choi, Sang Woo

doi:10.4028/0-87849-412-x.743

Cited by 1 publication

(2 citation statements)

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“…These sensors need to be deployed directly inside jet engines because of reliability and noise requirements, and hence, they should be able to withstand a temperature range of 500 to 1000°C for a mission lifetime up to 100 000 h [4]. Additionally, nuclear power industries require a high-temperature sensing technique for various non-destructive testing (NDT) and nondestructive evaluation (NDE) applications [5], [6]. For example, in the typical secondary coolant system of nuclear power plants, ultrasonic NDT of steel components is usually performed at temperatures up to 400°C [7].…”

Section: Introductionmentioning

confidence: 99%

“…The most common HT piezoelectric material, quartz, possesses high electrical resistivity (>10 17 Ω·cm at room temperature), high mechanical quality factor, and excellent high-temperature stability. Nevertheless, its low electromechanical and piezoelectric coefficients, high losses above ~450°C, and α to β phase transition temperature of 573°C limit the use of quartz for applications at temperatures above 600°C [4]- [6]. GaPO 4 shows features similar to quartz, such as high electrical resistivity and mechanical quality factor, but it also exhibits high electromechanical coupling and greater piezoelectric sensitivity until the α to β phase transition occurs (<970°C).…”

Section: Introductionmentioning

confidence: 99%

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High-temperature electromechanical characterization of AlN single crystals

Kim

Dalmau

et al. 2015

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Hexagonal AlN is a non-ferroelectric material and does not have any phase transition up to its melting point (>2000°C), which indicates the potential use of AlN for hightemperature sensing. In this work, the elastic, dielectric, and piezoelectric constants of AlN single crystals were investigated at elevated temperatures up to 1000°C by the resonance method. We used resonators of five different modes to obtain a complete set of material constants of AlN single crystals. The electrical resistivity of AlN at elevated temperature (1000°C) was found to be greater than 5 × 10 cm. 10 Ω ⋅The resonance frequency of the resonators, which was mainly determined by the elastic compliances, decreased linearly with increasing temperature, and was characterized by a relatively low temperature coefficient of frequency, in the range of −20 to −36 ppm/°C. For all the investigated resonator modes, the elastic constants and the electromechanical coupling factors exhibited excellent temperature stability, with small variations over the full temperature range, <11.2% and <17%, respectively. Of particular significance is that due to the pyroelectricity of AlN, both the dielectric and the piezoelectric constants had high thermal resistivity even at extreme high temperature (1000°C). Therefore, high electrical resistivity, temperature independence of electromechanical properties, as well as high thermal resistivity of the elastic, dielectric, and piezoelectric properties, suggest that AlN single crystals are a promising candidate for high-temperature piezoelectric sensing applications.

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Section: Introductionmentioning

confidence: 99%