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

Journal Article · Tue Mar 01 04:00:00 EST 1983 · J. Mater. Energy Syst.; (United States)

DOI:https://doi.org/10.1007/BF02833444· OSTI ID:5488354

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 2.25 Cr-1 Mo, 5 Cr-0.5 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 (about 50 pct) relative to INCOLOY Alloy 800, and provide at least equivalent corrosion resistance.

• Research Organization: Exploratory Chemistry Division I, Sandia National Laboratories, Livermore, CA 94550
• OSTI ID: 5488354
• Journal Information: J. Mater. Energy Syst.; (United States), Journal Name: J. Mater. Energy Syst.; (United States) Vol. 4:4; ISSN JMSMD
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
141000* -- Solar Collectors & Concentrators
36 MATERIALS SCIENCE
360100 -- Metals & Alloys
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CENTRAL RECEIVERS
CHALCOGENIDES
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
COATINGS
CORROSION RESISTANCE
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
COST
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INCOLOY 800
INCOLOY ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MATERIALS TESTING
MOLTEN SALTS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
OXIDES
OXYGEN COMPOUNDS
PROTECTIVE COATINGS
SALTS
SOLAR RECEIVERS
STAINLESS STEEL-316
STAINLESS STEELS
STEELS
TESTING