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Depth-Selective Diagnostics of Thermal Barrier Coatings Incorporating Thermographic PhosphorsThermographic phosphors have been previously demonstrated to provide effective non- contact, emissivity-independent surface temperature measurements. Because of the translucent nature of thermal barrier coatings (TBCs), thermographic-phosphor-based temperature measurements can be extended beyond the surface to provide depth-selective temperature measurements by incorporating the thermographic phosphor layer at the depth where the temperature measurement is desired. In this paper, the use of thermographic phosphor (Y2O3:Eu) luminescence decay time measurements is demonstrated for the first time for through-the-thickness temperature readings up to 1000 C with the phosphor placed beneath a 100-micron-thick TBC (plasma-sprayed 8wt% yttria-stabilized zirconia). With an appropriately chosen excitation wavelength and detection configuration, it is shown that sufficient phosphor emission is generated to provide effective temperature measurements, despite the attenuation of both the excitation and emission intensities by the overlying TBC. This depth-selective temperature measurement capability should prove particularly useful for TBC diagnostics, where a large thermal gradient is typically present across the TBC thickness.
Document ID
Document Type
Preprint (Draft being sent to journal)
Eldridge, J. I.
(NASA Glenn Research Center Cleveland, OH, United States)
Bencic, T. J.
(NASA Glenn Research Center Cleveland, OH, United States)
Allison, S. W.
(Oak Ridge National Lab. TN, United States)
Beshears, D. L.
(Oak Ridge National Lab. TN, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Structural Mechanics
Meeting Information
49th International Instrumentation Symposium(Orland, FL)
Funding Number(s)
OTHER: 22-713-82-52
Distribution Limits
Public Use Permitted.
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