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Proceedings Paper

Development of a sapphire optical pressure sensor for high-temperature applications
Author(s): David A. Mills; Dylan Alexander; Ghatu Subhash; Mark Sheplak
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Paper Abstract

This paper presents the fabrication, packaging, and characterization of a sapphire optical pressure sensor for hightemperature applications. Currently available instrumentation poses significant limitations on the ability to achieve realtime, continuous measurements in high-temperature environments such as those encountered in industrial gas turbines and high-speed aircraft. The fiber-optic lever design utilizes the deflection of a circular platinum-coated sapphire diaphragm to modulate the light reflected back to a single send/receive sapphire optical fiber. The 7 mm diameter, 50 μm thick diaphragm is attached using a novel thermocompression bonding process based on spark plasma sintering technology. Bonds using platinum as an intermediate layer are achieved at a temperature of 1200°C with a hold time of 5 min. Initial characterization of the bond interface using a simple tensile test indicates a bond strength in excess of 12 MPa. Analysis of the buckled diaphragm after bonding is also presented. The packaged sensor enables continuous operation up to 900°C. Room-temperature characterization reveals a first resonance of 18.2 kHz, a flat-band sensitivity of -130 dB re 1 V/Pa (0.32 μV/Pa) from 4-20 kHz, a minimum detectable pressure of 3.8 Pa, and a linear response up to 169 dB at 1.9 kHz.

Paper Details

Date Published: 5 June 2014
PDF: 15 pages
Proc. SPIE 9113, Sensors for Extreme Harsh Environments, 91130H (5 June 2014); doi: 10.1117/12.2050598
Show Author Affiliations
David A. Mills, Univ. of Florida (United States)
Dylan Alexander, Univ. of Florida (United States)
Ghatu Subhash, Univ. of Florida (United States)
Mark Sheplak, Univ. of Florida (United States)

Published in SPIE Proceedings Vol. 9113:
Sensors for Extreme Harsh Environments
Debbie G. Senesky; Sachin Dekate, Editor(s)

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