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Development of Advanced Thermal and Environmental Barrier Coatings Using a High-Heat-Flux Testing ApproachThe development of low conductivity, robust thermal and environmental barrier coatings requires advanced testing techniques that can accurately and effectively evaluate coating thermal conductivity and cyclic resistance at very high surface temperatures (up to 1700 C) under large thermal gradients. In this study, a laser high-heat-flux test approach is established for evaluating advanced low conductivity, high temperature capability thermal and environmental barrier coatings under the NASA Ultra Efficient Engine Technology (UEET) program. The test approach emphasizes the real-time monitoring and assessment of the coating thermal conductivity, which initially rises under the steady-state high temperature thermal gradient test due to coating sintering, and later drops under the cyclic thermal gradient test due to coating cracking/delamination. The coating system is then evaluated based on damage accumulation and failure after the combined steady-state and cyclic thermal gradient tests. The lattice and radiation thermal conductivity of advanced ceramic coatings can also be evaluated using laser heat-flux techniques. The external radiation resistance of the coating is assessed based on the measured specimen temperature response under a laser- heated intense radiation-flux source. The coating internal radiation contribution is investigated based on the measured apparent coating conductivity increases with the coating surface test temperature under large thermal gradient test conditions. Since an increased radiation contribution is observed at these very high surface test temperatures, by varying the laser heat-flux and coating average test temperature, the complex relation between the lattice and radiation conductivity as a function of surface and interface test temperature may be derived.
Document ID
Document Type
Preprint (Draft being sent to journal)
Zhu, Dongming
(Army Research Lab. Cleveland, OH, United States)
Miller, Robert A.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Nonmetallic Materials
Meeting Information
Meeting: 27th Annual International Conference on Advanced Ceramics and Composites
Location: Cocoa Beach, FL
Country: United States
Start Date: January 26, 2003
End Date: January 31, 2003
Distribution Limits
Work of the US Gov. Public Use Permitted.
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