Protective coatings for alloys in contact with molten drawsalt (NaNO/sub 3/-KNO/sub 3/)
Molten drawsalt (NaNO/sub 3/-KNO/sub 3/) is being considered as the energy transfer and storage medium for many solar central receiver applications. In an effort to reduce the cost of the containment material while maintaining corrosion resistance, alloys with aluminide coatings have been examined while in contact with molten drawsalt for more than 6000 hours at 600/sup 0/C. The alloys examined were 2-1/4 Cr-1 Mo, 5 Cr-1/2 Mo, and 9 Cr-1 Mo low-alloy steels, and 316 stainless steel. The results show a steady, albeit slow, net weight loss over the course of the experiment. The weight loss has been attributed to spalling of Al/sub 2/O/sub 3/ from the surface (the occurrence of Al/sub 2/O/sub 3/ is a result of the aluminizing process) and dissolution of corrosion products NaAlO/sub 2/ and/or NaFeO/sub 2/ during post-immersion handling. Scanning electron micrographs of exposed surfaces revealed little or no corrosion of the base metal. It has been concluded that aluminide coated alloys could provide significant cost savings (approx. 50%) relative to Incoloy 800, and provide at least equivalent corrosion resistance.
- Research Organization:
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6741849
- Report Number(s):
- SAND-82-8028; ON: DE83002505
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CHROMIUM-MOLYBDENUM STEELS
CORROSION PROTECTION
PROTECTIVE COATINGS
MOLTEN SALTS
CORROSIVE EFFECTS
POTASSIUM NITRATES
SODIUM NITRATES
STAINLESS STEEL-316
TOWER FOCUS COLLECTORS
ALUMINIUM OXIDES
CORROSION PRODUCTS
EXPERIMENTAL DATA
HEAT STORAGE
HEAT TRANSFER FLUIDS
MATERIALS TESTING
PHASE DIAGRAMS
WEIGHT
ALKALI METAL COMPOUNDS
ALLOYS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
COATINGS
CONCENTRATING COLLECTORS
CORROSION RESISTANT ALLOYS
DATA
DIAGRAMS
ENERGY STORAGE
EQUIPMENT
FLUIDS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NITRATES
NITROGEN COMPOUNDS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
SALTS
SODIUM COMPOUNDS
SOLAR COLLECTORS
SOLAR EQUIPMENT
STAINLESS STEELS
STEELS
STORAGE
TESTING
CSP
Concentrating Solar Power
140702* - Solar Thermal Power Systems- Central Receiver
360105 - Metals & Alloys- Corrosion & Erosion