Protective coatings for alloys in contact with molten drawsalt (NaNO/sub 3/-KNO/sub 3/)

Technical Report · Wed Sep 01 04:00:00 EDT 1982

DOI:https://doi.org/10.2172/6741849· OSTI ID:6741849

Carling, R. W.; Bradshaw, R. W.; Mar, R. W.

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 Labs., Livermore, CA (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6741849
• Report Number(s): SAND-82-8028; ON: DE83002505
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140702* -- Solar Thermal Power Systems-- Central Receiver
36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
ALKALI METAL COMPOUNDS
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-MOLYBDENUM STEELS
CHROMIUM-NICKEL STEELS
COATINGS
CONCENTRATING COLLECTORS
CORROSION PRODUCTS
CORROSION PROTECTION
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
CSP
Concentrating Solar Power
DATA
DIAGRAMS
ENERGY STORAGE
EQUIPMENT
EXPERIMENTAL DATA
FLUIDS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HEAT STORAGE
HEAT TRANSFER FLUIDS
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MATERIALS TESTING
MOLTEN SALTS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NITRATES
NITROGEN COMPOUNDS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
POTASSIUM COMPOUNDS
POTASSIUM NITRATES
PROTECTIVE COATINGS
SALTS
SODIUM COMPOUNDS
SODIUM NITRATES
SOLAR COLLECTORS
SOLAR EQUIPMENT
STAINLESS STEEL-316
STAINLESS STEELS
STEELS
STORAGE
TESTING
TOWER FOCUS COLLECTORS
WEIGHT