Effect of Starting Microstructure on Thermal Properties forAs-Sprayed and Thermally Exposed Plasma-Sprayed YSZ Coatings

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Journal of the American Ceramic Society

OSTI ID:988707

Wang, Hsin ^[1]; Tan, Y ^[2]; Longtin, J P ^[2]; Sampath, S ^[2]

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1. ORNL
2. State University of New York, Stony Brook

Thermal barrier coatings (TBCs) experience thermal gradients, excessive temperature, and high heat flux from hot gases in turbines during service. These extended thermal effects induce sin-tering and significant microstructure changes, which alter the resulting thermal conductivity within the TBCs. In this study plasma-sprayed Yttria Stabilized Zirconia (YSZ) TBCs using dif-ferent starting powders and process parameters were subjected to thermal aging at several tem-peratures and time intervals, after which their thermal conductivity was measured at room tem-perature. The thermal conductivity results are analyzed by introducing the Larson-Miller pa-rameter describing the creep behavior of thermal conductivity increase with annealing tempera-ture and time. One set of selected coatings was also annealed under the same conditions and the thermal conductivity was measured at elevated temperatures. The temperature-dependent ther-mal conductivity data is analyzed and used to predict long-term thermal behavior for general YSZ coating design.

• Research Organization: Oak Ridge National Laboratory (ORNL); High Temperature Materials Laboratory
• Sponsoring Organization: EE USDOE - Office of Energy Efficiency and Renewable Energy (EE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 988707
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 3 Vol. 92; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
CREEP
MICROSTRUCTURE
MORPHOLOGICAL CHANGES
PROTECTIVE COATINGS
TBCs
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
TURBINES
YTTRIUM OXIDES
ZIRCONIUM OXIDES