Corrosion Behavior of 304 Stainless Steel in Molten Nitrate Salt at Different Temperatures

Corrosion behavior of 304 stainless steel in molten salt at different temperatures (400,450,500,565℃) was studied by corrosion kinetic method, corrosion surface observation and micro area composition analysis; the molten salt was composed of 60wt%NaNO₃+40wt%KNO₃. The results show that the corrosion rate of the tested steel in the molten salt increased with the increase of temperature, and reached 99.6×10^-5 mg·cm^-2·h^-1 at 565℃. There was only few oxidation corrosion products on the surface of the tested steel at 400℃. There was a small amount of Fe₂O₃ on the surface at 450℃ and 500℃. The oxidation corrosion products mainly content of Fe₂O₃ and (Fe, Cr) ₃O₄ were formed on the surface at 565℃, with the increase of temperature, the content of Fe₂O₃ increased considerably and the oxidation corrosion degree aggravated.