Cyclic oxidation and hot corrosion of Al2O3 or Y2O3-dispersed low-temperature chromizing coating

Chromium coatings with and without Al2O3 or Y2O3 particles were prepared by chromizing the as-deposited Ni-film with and without Al2O3 or Y2O3 particles using a conventional pack-cementation method at 800 °C. The cyclic oxidation at 800 °C and hot corrosion in molten 75% Na2SO4+25% NaCl at 800 °C of the three different chromizing coatings were investigated. The effects of Al2O3 or Y2O3 on the cyclic oxidation and hot corrosion behavior of the chromizing coatings were discussed. Microstructure results show that the codeposited Al2O3 or Y2O3 particles significantly retard the grain growth of the chromizing coating, which increases the cyclic oxidation and hot corrosion resistance of the chromizing coatings, due to the more rapid formation of purer and denser chromia scale.