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Title: Embedded Optical Sensors for Thermal Barrier Coatings

Abstract

In the second year of this program on developing embedded optical sensors for thermal barrier coatings, our research has focused three topics: (1) Eu{sup 3+} doping for temperature sensing, (2) the effect of long-term, high-temperature aging on the characteristics of the luminescence from the Eu{sup 3+} ions of 8YSZ materials, (3) construction of a fiber-optic based luminescence detector system. It has been demonstrated that the variation in luminescence lifetime with temperature is identical for electron-beam evaporated Eu-doped YSZ coatings as for bulk ceramics of the same composition. Experiments indicate that the luminescence lifetime method of measuring temperatures is sensitive up to 1150 C for both Eu-doped YSZ coatings and Eu-doped Gd{sub 2}Zr{sub 2}O{sub 7}. Furthermore, the technique is sensitive up to 1250 C for the composition Eu{sub 2}Zr{sub 2}O{sub 7}. The luminescence spectra Eu-doped YSZ are insensitive to long-term aging at high-temperatures, even to 195 hours at 1425 C, except for a small frequency shift that is probably too small in measure except with instruments of the highest spectral resolution. The temperature of 1425 C is much higher than present engines attain or even planned in the foreseeable future. Nevertheless, experiments are on-going to explore longer term exposures. A fiber-opticmore » based luminescence system has been constructed in which the hottest section of fiber operates to at least 1250 C.« less

Authors:
Publication Date:
Research Org.:
University of California
Sponsoring Org.:
USDOE
OSTI Identifier:
875889
DOE Contract Number:
FG26-03NT41794
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 47 OTHER INSTRUMENTATION; AGING; CERAMICS; PROTECTIVE COATINGS; ENGINES; LUMINESCENCE; RESOLUTION; PROBES; DESIGN; TEMPERATURE MONITORING; EUROPIUM OXIDES; YTTRIUM OXIDES; STRONTIUM OXIDES; ZIRCONIUM OXIDES; GADOLINIUM OXIDES

Citation Formats

David R. Clarke. Embedded Optical Sensors for Thermal Barrier Coatings. United States: N. p., 2005. Web. doi:10.2172/875889.
David R. Clarke. Embedded Optical Sensors for Thermal Barrier Coatings. United States. doi:10.2172/875889.
David R. Clarke. Wed . "Embedded Optical Sensors for Thermal Barrier Coatings". United States. doi:10.2172/875889. https://www.osti.gov/servlets/purl/875889.
@article{osti_875889,
title = {Embedded Optical Sensors for Thermal Barrier Coatings},
author = {David R. Clarke},
abstractNote = {In the second year of this program on developing embedded optical sensors for thermal barrier coatings, our research has focused three topics: (1) Eu{sup 3+} doping for temperature sensing, (2) the effect of long-term, high-temperature aging on the characteristics of the luminescence from the Eu{sup 3+} ions of 8YSZ materials, (3) construction of a fiber-optic based luminescence detector system. It has been demonstrated that the variation in luminescence lifetime with temperature is identical for electron-beam evaporated Eu-doped YSZ coatings as for bulk ceramics of the same composition. Experiments indicate that the luminescence lifetime method of measuring temperatures is sensitive up to 1150 C for both Eu-doped YSZ coatings and Eu-doped Gd{sub 2}Zr{sub 2}O{sub 7}. Furthermore, the technique is sensitive up to 1250 C for the composition Eu{sub 2}Zr{sub 2}O{sub 7}. The luminescence spectra Eu-doped YSZ are insensitive to long-term aging at high-temperatures, even to 195 hours at 1425 C, except for a small frequency shift that is probably too small in measure except with instruments of the highest spectral resolution. The temperature of 1425 C is much higher than present engines attain or even planned in the foreseeable future. Nevertheless, experiments are on-going to explore longer term exposures. A fiber-optic based luminescence system has been constructed in which the hottest section of fiber operates to at least 1250 C.},
doi = {10.2172/875889},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Nov 09 00:00:00 EST 2005},
month = {Wed Nov 09 00:00:00 EST 2005}
}

Technical Report:

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  • In this first year of the program we have focused on the selection of rare-earth dopants for luminescent sensing in thermal barrier coating materials, the effect of dopant concentration on several of the luminescence characteristics and initial fabrication of one type of embedded sensor, the ''red-line'' sensor. We have initially focused on erbium as the lanthanide dopant for luminescence doping of yttria-stabilized zirconia and europium as the lanthanide for luminescence doping of gadolinium zirconate. The latter exhibits a temperature-dependent luminescence lifetime up to at least 1100 C. A buried layer, ''red-line'' sensor in an electron-beam deposited yttria-stabilized zirconia coating withmore » erbium has been demonstrated and exhibits a temperature-dependent luminescence lifetime up to at least 400 C.« less
  • The third year of this program on developing embedded optical sensors for thermal barrier coatings has been devoted to two principal topics: (i) continuing the assessment of the long-term, thermal cycle stability of the Eu{sup 3+} doped 8YSZ temperature sensor coatings, and (ii) improving the fiber-optic based luminescence detector system. Following the earlier, preliminary findings, it has been found that not only is the luminescence from the sensors not affected by prolonged thermal cycling, even after 195 hours at 1425 C, but the variation in luminescence lifetime with temperature remains unchanged. As the temperature of 1425 C is much highermore » than present engines attain or even planned in the foreseeable future, our findings indicate that the Eu{sup 3+} doped thermal barrier coating sensors are very robust and have the potential of being stable throughout the life of coatings. Investigation of Eu{sup 3+} doped coatings prepared by plasma-spraying exhibited the same luminescence characteristics as those prepared by electron-beam evaporation. This is of major significance since thermal barrier coatings can be prepared by both process technologies. A fiber-optic based luminescence system has been constructed in which the hottest section of fiber operates to at least 1250 C.« less
  • No abstract provided.
  • This report summarizes LDRD project number 151365, \Dynamic Temperature Measurements with Embedded Optical Sensors". The purpose of this project was to develop an optical sensor capable of detecting modest temperature states (<1000 K) with nanosecond time resolution, a recurring diagnostic need in dynamic compression experiments at the Sandia Z machine. Gold sensors were selected because the visible re ectance spectrum of gold varies strongly with temperature. A variety of static and dynamic measurements were performed to assess re ectance changes at di erent temperatures and pressures. Using a minimal optical model for gold, a plausible connection between static calibrations andmore » dynamic measurements was found. With re nements to the model and diagnostic upgrades, embedded gold sensors seem capable of detecting minor (<50 K) temperature changes under dynamic compression.« less