Corrosion behavior of the NiCrAlY and NiSiAlY alloys with salt mixtures of NaCl/Na₂SO₄

The corrosion behavior of the NiCrAlY and NiSiAlY alloys with the salt mixtures of various NaCl/Na2SO4 ratios was investigated at 750 degrees C. The tested alloys corroded by 100% Na2SO4, 100% NaCl and NaCl/Na2SO4 salt mixtures (75/25, 50/50, and 25/75 wt. %) exhibited distinctive resistance and behavior. The NiCrAlY alloys suffered more severe corrosion with the increasing proportion of NaCl in the salt mixtures. However, the NiSiAlY alloys caused more intense attack when exposed to the salt mixtures of NaCl/Na2SO4 (75/25, 50/50, and 25/75 wt.). The complex mechanisms and the impact of salt composition on corrosion are also discussed.