Laser cladding Ni35A120Fe intermetallic coating for resisting high-temperature oxidation and hot corrosion

With Ni/Al cladding powders and coaxial powder-feeding mode, Ni35A12OFe intermetallic coating was successfully prepared by laser cladding. The optimizing principles of processing parameters of laser cladding were proposed. The shaping and microstructure of laser cladding coating were analyzed. The experimental results indicated that lower laser power; slower scanning velocity and larger beam diameter could ensure excellent shaping and metallurgical quality. Under the optimum processing, laser cladding Ni35Al2OFe intermetallic coating was free of porosity and cracks and a fully metallurgical adhesion was achieved between the coating and the substrate. The microstructure was composed of refine ?-NiAl intermetallic phase as the base and a few dispersed ? phase particles precipitated along crystal grain boundaries and within the grains. The formation of ?-NiAl phase dissolved with Fe, precipitation of ductile ? phase and refined crystal grains were favorable of not only higher strength but also enough ductility and toughness of laser cladding coating.