Effects of Laser Remelting on Microstructural Characteristics and Hot Corrosion Behavior of MСrAlY Coating Prepared by Plasma Spraying

Plasma spraying technique was used to prepare MCrAlY coating on TiAl alloy surface, the coating was treated through the laser remelting process, and then scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to analyze surface topography and phase composition before and after hot corrosion behavior of the coating. Results indicate that after laser remelting treatment, lamellar structure of the coating disappears with improved compactness and most defects like pores and inclusion eliminated. Plasma sprayed MCrAlY coating can significantly improve hot corrosion property of TiAl alloy, which can be further improved after laser remelting. MCrAlY coating mainly experiences surface oxidation reaction and internal sulfurization reaction during the hot corrosion in the high-temperature molten salt, which mainly generate corrosion products such as Al2O3, Cr2O3, NiO, NiCr2O4, Ni3S2 and CrS.