Hot corrosion behavior of Ni-16Cr-xAl based alloys in mixture of Na2SO4-NaCl at 600 °C

The hot corrosion behaviors of Ni-16Cr-xAl(x=4.5%, 6.8%, 9.0%, mass fraction) based alloys in Na2SO4-25% NaCl molten salts at 600 °C were investigated. The effects of pre-oxidation and Al content on the resistance to hot corrosion were examined. The hot corrosion resistance of Ni-16Cr-xAl based alloy with Al addition from 4.5% to 9.0% increases with increasing Al content. The alloy with Al content of 9.0% shows the highest hot corrosion resistance among the examined alloys because more β-NiAl phases are obtained to sustain the Al2O3 scale repaired during hot corrosion. Pre-oxidized specimens have a superior hot corrosion resistance compared with the as-cast specimens, due to a protective oxide scale formed after pre-treatment.