Evaluation of performance of thermal barrier coatings under simulated industrial/utility gas turbine conditions
Corrosion tests were performed on state-of-the-art yttria-stabilized zirconia Thermal Barrier Coatings (TBC), under development for cleanfueled aircraft gas turbine service, applied to IN-738 substrates. Small burner rig tests with Na/sub 2/SO/sub 4/ condensate were conducted on coated disc specimens to simulate present industrial/utility gas turbine operating conditions in an accelerated manner. Specimens were evaluated with appropriate techniques to establish specific corrosion effects and mechanisms where possible. In addition, predictions were made for condensates which might be expected to form from impurities in contaminated petroleum distillates and from future coal derived fuels. Sprayed salt and crucible melt tests were run on coated pin specimens exposed to these simulated future gas turbine operating conditions to evaluate the predictions. In general, hot corrosion condensates penetrated to the substrate metal by flowing through the continuous porosity of the TBC. Intrinsically, there appears to be no corrosive effect on the zirconia itself. However, penetration of corrosive products to the substrate resulted in both accelerated substrate attack as well as spalling of the ceramic coating due to internal stresses generated by the condensates during thermal cycling. Compared to the TBC coated superalloy, bare IN-738 survives 2 to 5 times longer under the same test conditions. The porous TBC holds a reservoir fo condensate readily available for reaction.
- Research Organization:
- General Electric Co., Schenectady, NY (USA). Gas Turbine Div.
- DOE Contract Number:
- EC-77-C-05-5402
- OSTI ID:
- 6273126
- Report Number(s):
- TID-29086
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CERAMICS
MATERIALS TESTING
COAL LIQUIDS
COMBUSTION PRODUCTS
COATINGS
GAS TURBINES
CORROSION PROTECTION
PETROLEUM
ZIRCONIUM OXIDES
CORROSION RESISTANCE
CORROSIVE EFFECTS
EXPERIMENTAL DATA
GRAPHS
HEAT TRANSFER
INDUSTRIAL PLANTS
TABLES
TEMPERATURE DEPENDENCE
THEORETICAL DATA
THERMAL POWER PLANTS
CHALCOGENIDES
DATA
DATA FORMS
ENERGY SOURCES
ENERGY TRANSFER
FOSSIL FUELS
FUELS
INFORMATION
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
POWER PLANTS
TESTING
TRANSITION ELEMENT COMPOUNDS
TURBINES
TURBOMACHINERY
ZIRCONIUM COMPOUNDS
200104* - Fossil-Fueled Power Plants- Components
360105 - Metals & Alloys- Corrosion & Erosion
360205 - Ceramics
Cermets
& Refractories- Corrosion & Erosion