Thermocyclic behavior of variously stabilized EB-PVD thermal barrier coatings
- German Aerospace Research Establishment, Cologne (Germany). Inst. of Materials Research
The demand for increasing gas inlet temperatures in modern gas turbines up to 1,500 C and above is the main reason for the need for more reliable thermal barrier coatings. New ceramics should provide higher phase stability and better resistance against chemical attack by pollutants in the combustion gas. Electron beam-- physical vapor deposition (EB-PVD) processed, ZrO{sub 2}-based TBCs were generated on bond-coated superalloy directionally solidified (DS) samples. Common yttria-stabilized zirconias of two different compositions, as well as novel stabilizers like CeO{sub 2} and La{sub 2}O{sub 3}, were investigated. A columnar structure was established during high-rate deposition in all cases. Diameter, degree of ordering of the columns, and phase composition depended on stabilizer oxide and content. The role of differences of vapor pressures is addressed with regard to chemical homogeneity of the coatings. The performance of the TBCs having various stabilizers was investigated in a cyclic oxidation furnace test and in a burner rig at Mach 0.3. The results were correlated to the type and content of stabilizer with special emphasis on phase analyses. Evaporation of new ceramic compositions necessitates special precautions because the vapor pressures of the components may differ too much. A new dual-source evaporation coater allows the production of these innovative TBCs with close control of chemistry. The potential of the equipment will be discussed.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 566220
- Report Number(s):
- CONF-960608--
- Journal Information:
- Journal of Engineering for Gas Turbines and Power, Journal Name: Journal of Engineering for Gas Turbines and Power Journal Issue: 4 Vol. 119; ISSN JETPEZ; ISSN 0742-4795
- Country of Publication:
- United States
- Language:
- English
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