Hot corrosion behaviour of yttrium and aluminium modified wear resistance coating alloy in mixed sulphate at 900°C

Abstract The wear resistance coating alloy Tribaloy T-900 modified by aluminium and yttrium was prepared by mechanical alloying. The hot corrosion behaviour of modified and unmodified alloys was investigated at 900 °C. Results revealed that T-900AlY with aluminium plus yttrium showed the superior hot corrosion resistance. The Yttrium addition promoted the selective oxidation of Al and Cr and accelerated a continuous oxide layer of Al2O3 and Cr2O3. The oxides layer acted as a barrier against the molten salt attack. The early formation of chromia and alumina layer obstructed the formation of outer NiO and MoO3, which were more susceptible to the liquid salt attack.