Hot Corrosion
Definition
Accelerated degradation of a superalloy or coated turbine component by molten sulfate or vanadate deposits that flux and dissolve the protective oxide scale, allowing continued rapid attack.
- Affected components
- Superalloy or coated turbine parts
- Agents
- Molten sulfate or vanadate deposits
- Mechanism
- Flux dissolves protective oxide scale
- Result
- Accelerated, continued material attack
Common questions
How does hot corrosion differ from ordinary high-temperature oxidation?+
Ordinary oxidation forms a stable protective scale that slows further attack, while hot corrosion involves molten salt deposits that actively dissolve or flux that scale away, exposing fresh metal to continued rapid degradation rather than self-limiting protection.
What contaminants commonly trigger hot corrosion in turbine failure investigations?+
Sulfur from fuel combustion combined with sodium or vanadium, often introduced through contaminated fuel, sea-salt-laden intake air in marine environments, or ash-forming impurities, are common sources investigators look for when hot corrosion is suspected.
Related terms
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- Grain-Boundary Sliding
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- Minimum Creep Rate
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- Reheat Cracking
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