The Influence Of Laser Power Of Ni Base-WC Cladding Layer Organization And Performance

In recent years, preparation Ni-based WC composite coating in the metalsubstrate surface has been widely attention, Due to the coating can significantlyimprove the surface hardness and wear resistance, Scholars at home and abroad haveprepared the coating with a variety of surface treatment in different substrate andacquired the rich research achievements in this respect, but it is rarely reported andnot enough details on effects of the coating organization and property under differentlaser power, It is necessary to further discuss the effects of the laser power on theorganization and property of Ni-based WC coating, to provide a reference to prepareNi based composite coating of high performance.In this experiment, the Ni-based WC cladding layer was prepared on316Lstainless steel surface by using the HGL-6000crosscurrent CO2laser. The surfacemorphology, organization, composition and phase of cladding layer are analyzedusing optical microscope(OM), scanning electron microscope(SEM) and its attachedspectrometer(EDS) and XRD diffraction instrument,and the different laser powerinfluence on organization of Ni base-WC cladding layer is examined. The hardnesscurve of cladding layers section was tested by using the digital micro hardness testerunder different laser power, the corrosion current and corrosion potential of316Lsubstrate and the cladding layers under different laser power were measured byelectrochemical workstation, and get the Tafel polarization curve.The experiment results show that the cladding specimen is divided into threeregions: the cladding layer, combining zone and heat affecting zone according to thesection macrostructure of it. The top microstructure of cladding layer is isometriccrystal, the center is columnar dendrites and binding region near the substrate is planecrystal. When the laser power density increases, the organization of the cladding layerbecomes smaller gradually within2500W-3500W.When the laser power density is4000W, the junction occurs a burning phenomenon. The organization is bigger than itof3500W due to the bigger dilution rate. Enrichment of Fe, Ni appears in thecladding layer while segregation of Cr, W appears in grain boundary. The phase of thecladding layer is mainly (Fe, Ni), SiC, Ni4W, CrSi2and some of the intermetalliccompound. In terms of hardness change, the dilution rate of the cladding layerbecome larger with the increase of the power, and the average hardness of claddinglayer down. In terms of corrosion resistance, the corrosion current of the3500Wcladding layer was similar to substrate, the corrosion resistance of other powercladding layer is not higher than substrate.