Abstract: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.

Key words: electrodeposition; chromizing coating; cyclic oxidation; hot corrosion