Microstructure and properties of Ni based alloy composite coating by laser cladding-ion sulfurizing process

The composite layer was produced on 45 steel substrate by laser cladding and low temperature ion sulfurizing process. The microstructure and phase composition of laser cladding layer and sulfurizing layer were studied by the means of SEM, EMPA and XRD. The wear resistance and corrosion resistance of the layer by laser cladding and laser cladding and sulfurizing were also studied. The results showed that phase composition of Ni-based alloy laser cladding coating mainly includes γ-(Fe, Ni), Fe_0.64Ni_0.36, M₂₃C₆, WC, M₇C₃ and Fe₂B and so on, and its microstructure hardness is up to 740 HV_0.2. Sulfide layer was produced on the Ni-based alloy coating with low temperature ion sulfurizing process, which is loose and porous, is piled up by the sharp island micro nan-scale particles. Compared with Ni-based alloy laser cladding layer, the friction coefficient and the wear loss of the modified composite layer decrease significantly, excellent antifriction and wear resistance can be obtained. After low temperature ion sulfurizing treatment, the corrosion potential decreases, and the corrosion current density increases and the corrosion resistance of Ni-based alloy laser cladding layer decreases slightly.