Corrosion characteristics of Inconel 625 cladding layer and NiCrMoAl cladding layer in molten NaCl-KCl and NaCl-KCl-Na2SO4

The high-temperature corrosion characteristics of Inconel 625 and NiCrMoAl cladding layers were investigated in molten NaCl-KCl and NaCl-KCl-K2SO4. In NaCl-KCl, the corrosion was dominated by “electrochemical” mechanism, subsequently triggering “chlorine-active corrosion” mechanism. NiCrMoAl cladding layer provided significantly higher corrosion resistance than Inconel 625 cladding layer, due to the generated greatly Al2O3 enhanced the difficulty of inward diffusion of Cl-. In NaCl-KCl-K2SO4, protective Al2O3 and Cr2O3 faced “basic fluxing” mechanism, considerably aggravating the corrosion. Additionally, Al easily reacted with SO42-, which further consumed Al and generated free S, causing NiCrMoAl cladding layer to suffer serious corrosion than Inconel 625 cladding layer.