Corrosion resistance of Hastelloys in molten metal-chloride heat-transfer fluids for concentrating solar power applications

摘要

Corrosion rates have been estimated for commercial Hastelloys C-276, C-22 and N types in eutectic molten salts containing NaCl, KC1 and ZnCl_2 using steady-state potentiodynamic method (0.2 mV s~(-1) within ～±30 mV from the open circuit voltage). Hastelloy C-276 exhibited the lowest corrosion rates of ～10 and 40 μm per year in 13.4NaCl-33.7KCl-52.9ZnCl_2 (mol%) salt at 250 and 500 ℃, respectively. The potentiodynamic method was validated by conducting traditional immersion test for corrosion rate estimation on C-276 Hastelloy in 13.4NaCl-33.7KCl-52.9ZnCl_2 (mol%) at 500 ℃ (corrosion rate ～50 μm per year). Among the samples evaluated, Hastelloy N showed highest corrosion rate of ＞150 μm per year at 500 ℃.