Hot Corrosion in Gas Turbines: Mechanisms; Alloy and Coating Development; Environmental Effects; Evaluation
NATIONAL MATERIALS ADVISORY BOARD (NAS-NAE) WASHINGTON DC
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Hot corrosion sulfidation in gas turbine engines has become a major problem because of the increased use of alloys low in chromium and the operation in environments containing alkali metal salts, especially near sea water. Sulfur can enter a gas turbine from the fuel, and chloride and sulfate salts from the air. There is little prospect for removal of these contaminants to such a degree as to eliminate the problem. However, from 10 to 75 of sea salt can be removed from the air intake to retard the attack. Data on tolerable levels of contaminants are needed. Engine testing is still the only reliable evaluation method to check improvements in the hot corrosion resistance of materials. Reproducibility in test results from test rigs in different laboratories is very poor, and further effort toward test rig standardization, correlation of the data between different tests, and interpolation of tests results and extension to different testing conditions, all are needed. Specific recommendations for attacking the hot corrosion problem are detailed in the report.
- Properties of Metals and Alloys
- Jet and Gas Turbine Engines