A series of mass loss corrosion rate laboratory experiments were conducted in molten nitrate-nitrite salts at 950–1300°F (510–705°C). Both nickel and iron alloys were tested. Nickel alloys with 15–20% chromium contents performed the best, while iron alloys, with low or no nickel exhibited poor corrosion resistance at high temperatures. Vapor aluminum diffusion treated stainless steel has good corrosion resistance but may be susceptible to localized attack and spoiling. The corrosion process combines oxidation and chromium dissolution. Protective chromium-rich oxide scales do not form, probably because chromium compounds are soluble in the salt. Salt corrosiveness increases drastically above 1200°F (650°C).