Fundamental study of the role of calcium sulfate in hot corrosion phenomena affecting the Navy s shipboard gas turbine engines
Abstract
Hot corrosion is a high-temperature oxidation phenomenon that results in the acceleratedwastage of metals by a molten salt film sta bilized by a highly oxidizing gas. The fused saltdeposit can be formed by condensation or physical deposition when sulfur-containin g fuels are combusted in the presence of an alkali salt containing aerosols. The Navy addressed the issue of sulfur contamination by requiring fuels to contain 15 ppm or less of sulfur. However, recently,hot corrosion has been reported in both marine and non-marin e service environments in aircraft and shipboard engines. Some additional factors complicating this more recent phenomenon include p articulate matter that varies widely across the world in chemical composition and concentration; the presence of calcium, magnesium, alumino-silicates; several chlorides and sulfates in seawater aerosol, carbon particulates, etc. Therefore, there is a need to more fully understand the mechanism of hot corrosion attack in shipboard engines in light of the current complex set of factors affectin g hot corrosion attack. The objective of the proposed project is to conduct a fundamental study of the hot corrosion mechanisms affe cting nickel-base superalloys used in naval and commercial aircraft as well as in the Navys shipboard gas turbine engines. In parti cular, the project will explore the role of calcium sulfate in this phenomenon. The technical approach will involve the response of different metallic alloys to different salts. The tests will be carried out at high temperatures for different periods of time under controlled atmospheres. Examples of salts include calcium sulfate plus sodium chloride. The effect of calcium sulfate additions to calcium-magnesium aluminosilicates (CMAS) will also be studied. Test coupons will be examined after exposure to corrosive environme nts using a variety of characterization methods. Post-test examination of the test coupons is expected to lead to a better understan ding of the hot corrosion phenomenon. The naval relevance of this project is the advancement in understanding a very important curre nt problem affecting the Navys mission in the topic area of Mission Capable, Persistent and Survivable Sea Platforms by addressin g two applicable research interests, i.e., advanced navalmaterials and corrosion control. The anticipated outcome of this resea rch will be a deeper understanding of the complex phenomenon of hot corrosion in polluted environments. The outcome of the project w ill have a positive impact on DoD capabilities, by offering insights to address this complex degradationphenomenon.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 20, 2021
- Source ID
- N000142112751
Entities
People
- Vilupanur A. Ravi
Organizations
- California State Polytechnic University, Pomona
- Office of Naval Research
- United States Navy