Microstructure and thermal conductivity of thermal barrier coatings processed by plasma spray and physical vapor deposition techniques
- Univ. of Utah, Salt Lake City, UT (United States). Dept. of Metallurgical Engineering
- Wright Lab., Wright Patterson AFB, OH (United States). Materials Directorate
Improvements in the efficiency of gas turbine require the highest operating temperatures possible. Because the Ni-base superalloys used as turbine materials rapidly lose strength and oxidize above 1,000 C, a reduction in service temperature is often accomplished by the use of thermal barrier coatings. The temperature dependence of the thermal conductivity of multilayer coatings made by a plasma spray technique as well as some coatings made by physical vapor deposition (PVD) was investigated. The multilayer coatings consisted of a varying number of layers of Al{sub 2}O{sub 3} and ZrO{sub 2} stabilized by 8% Y{sub 2}O{sub 3}. Plasma sprayed coatings exhibited a large reduction in thermal conductivity at all temperatures when compared to the bulk monolithic materials. This reduction was found to be due to porosity as well as thermal resistance brought about by interfaces in the coatings. A comparable reduction in thermal conductivity was achieved in monolithic ZrO{sub 2} as well as in a composite coating deposited by the PVD technique. Microstructural factors that may be responsible for this reduction are discussed.
- Sponsoring Organization:
- Department of the Air Force, Washington, DC (United States)
- OSTI ID:
- 490753
- Report Number(s):
- CONF-960401-; ISBN 1-55899-337-1; TRN: IM9729%%4
- Resource Relation:
- Conference: Spring meeting of the Materials Research Society (MRS), San Francisco, CA (United States), 8-12 Apr 1996; Other Information: PBD: 1996; Related Information: Is Part Of Layered materials for structural applications; Lewandowski, J.J. [ed.] [Case Western Reserve Univ., Cleveland, OH (United States)]; Ward, C.H. [ed.] [Air Force Office of Scientific Research, Bolling AFB, DC (United States)]; Jackson, M.R. [ed.] [General Electric Corporate R and D, Schenectady, NY (United States)]; Hunt, W.H. Jr. [ed.] [Alcoa Technical Center, Alcoa Center, PA (United States)]; PB: 325 p.; Materials Research Society symposium proceedings, Volume 434
- Country of Publication:
- United States
- Language:
- English
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