Development and High-Temperature Corrosion Performance of MCrAl(Y) Coatings Prepared by Electrochemical Deposition: A Brief Review.

Owing to good physical compatibility with high-temperature metallic structural materials, Cr2O3- or Al2O3-forming MCrAlY coatings have been extensively used to protect hot section components in aerospace and other fields from high-temperature corrosion. Currently, MCrAlY coatings are normally manufactured by means of physical methods, including electron beam-physical vapor deposition, magnetron sputtering, ion plating, thermal spray, etc. This review paper introduces novel nanocomposite-type MCrAl(Y) coatings prepared by electrochemical methods of nanocomposite electrodeposition and further modified "electrophoretic deposition + electrodeposition." The novel MCrAl(Y) coatings exhibit apparently enhanced ability in protective chromia or alumina scale formation, which can be attributed to the two-fold "nanoscale effect" of the dispersed particles and metal matrix grains. Based on a large amount of oxidation data of the nanocomposite-type NiCrAl coatings under different oxidation conditions, oxide maps showing the relationship between coatings' composition and type of the oxides are constructed to offer guidance for designing the novel coatings. Moreover, the "electrophoretic deposition + electrodeposition" method has been further applied to conveniently integrate a metallic-ceramic diffusion barrier into a MCrAl(Y) coating/Ni-based superalloy system which can significantly block the interdiffusion between the coating and the matrix. [ABSTRACT FROM AUTHOR]