Hot corrosion behaviour of single-phase platinum-modified aluminide coatings: Effect of Pt content and pre-oxidation

摘要

Hot corrosion behaviour of nickel-based aluminide coatings with different thicknesses of initial Pt plating was evaluated in the Na2SO4/NaCl (75:25, wt./wt.) salt mixture at 900 degrees C. Compared to plain aluminide, the Pt modified coatings showed better hot corrosion resistance by hindering the outward diffusion of undesirable elements from the substrate alloy. Pre-oxidation was confirmed to be capable of preventing molten salt from accessing the alloy surface and reversibly dissolving the oxide scale. Oxide growth and dissolution, acting as two competitive processes, occurred simultaneously and had an important impact on the entire performance of the Pt-modified aluminide coatings in hot corrosion.