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Journal of Sensors
Volume 2017 (2017), Article ID 9710763, 7 pages
https://doi.org/10.1155/2017/9710763
Research Article

Research and Implementation of a 1800°C Sapphire Ultrasonic Thermometer

1National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, Shanxi 030051, China
2School of Science, North University of China, Taiyuan, Shanxi 030051, China

Correspondence should be addressed to Fengbao Yang

Received 30 May 2017; Revised 30 October 2017; Accepted 5 November 2017; Published 14 December 2017

Academic Editor: Stephane Evoy

Copyright © 2017 Haijian Liang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A sapphire ultrasonic temperature sensor was produced in this study which possessed working stability, antioxidation properties, and small acoustic-signal attenuation. A method was developed to solve the problems of long periods (>0.5 h) and ultrahigh temperature (1800°C) in tests. The sensor adopted here had good sound transmission performance as well as the high thermal conductivity of sapphire single crystals (Al2O3), as ultrasonic waveguides. The ultrasonic waveguide was produced by the method of the laser-heated pedestal growth (LHPG method). Calibration experiments in a high temperature furnace found that, at high temperatures and long exposure, sapphire ultrasonic temperature sensors had good stability and repeatability, and it survived in 1600°C for 360 min. This sapphire ultrasonic temperature sensor has potential for applications in aircraft engines where monitoring of high temperatures is very important.