Materials corrosion of high temperature alloys immersed in 600°C binary nitrate salt

Technical Report · Fri Mar 01 04:00:00 EST 2013

DOI:https://doi.org/10.2172/1088090· OSTI ID:1088090

Kruizenga, Alan Michael ^[1]; Gill, David Dennis ^[1]; LaFord, Marianne Elizabeth ^[1]

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1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Thirteen high temperature alloys were immersion tested in a 60/40 binary nitrate salt. Samples were interval tested up to 3000 hours at 600ÀC with air as the ullage gas. Chemical analysis of the molten salt indicated lower nitrite concentrations present in the salt, as predicted by the equilibrium equation. Corrosion rates were generally low for all alloys. Corrosion products were identified using x-ray diffraction and electron microprobe analysis. Fe-Cr based alloys tended to form mixtures of sodium and iron oxides, while Fe-Ni/Cr alloys had similar corrosion products plus oxides of nickel and chromium. Nickel based alloys primarily formed NiO, with chromium oxides near the oxide/base alloy interface. In625 exhibited similar corrosion performance in relation to previous tests, lending confidence in comparisons between past and present experiments. HA230 exhibited internal oxidation that consisted of a nickel/chromium oxide. Alloys with significant aluminum alloying tended to exhibit superior performance, due formation of a thin alumina layer. Soluble corrosion products of chromium, molybdenum, and tungsten were also formed and are thought to be a significant factor in alloy performance.

• Research Organization: Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1088090
• Report Number(s): SAND--2013-2526; 456367
• Country of Publication: United States
• Language: English