High-temperature corrosion behavior of sputtered K38 nanocrystalline coatings with and without yttrium addition in molten sulfate at 900 °C

The high temperature corrosion behavior of sputtered Ni-based superalloy K38 nanocrystalline coatings with and without yttrium addition in molten sulfate (75 wt.% Na2SO4 + 25 wt.% K2SO4) was investigated at 900 °C in air. The results indicated that nanocrystallization significantly increased the corrosion resistance through the rapid formation of a protective oxide scale. The addition of yttrium in the nanocrystalline coating furthermore improved the corrosion resistance of the coating.