Microstructure And Properties Of Composite Coatings By Rotating Magnetic Field-assisted Laser Cladding

Laser cladding is an advanced method of preparing multi-function and high-performance modification coating on surface of substrate. Based on the theory of electromagnetic stirring, Ni60CuMoW and Fe60composite coating were successfully prepared by rotating magnetic field auxiliary synchronization powder feeding laser cladding technology. The effect of magnetic field intensity on microstructure and internal quality of Ni60CuMoW composite coating, and microstructure and mechanical properties of Fe60composite coating has been mainly analyzed. It is aiming to provide theoretical basis and certain technology foundation in rotating magnetic field auxiliary synchronization powder feeding laser cladding.In this paper, the effects on macro-morphology under different magnetic field intensity were analysized by using somatotype microscope. The effects on micro-morphology of the Ni60CuMoW and Fe60composite coating under different magnetic field intensity were analyzed by using Optical microscope(OM). The phase qualitative analysis of composite coating by X-ray diffraction (XRD). The microstructure feature was characterized and the effects on phase composition of cooating under different magnetic field intensity were analysized by scanning electrical microscope (SEM)and energy dispersive spectroscopy (EDS). The microhardness of samples section was tested by microhardness instrument, and the friction and wear performance of the Fe60coating has been tested using friction wear tester.The macro-morphology of coating of different magnetic field intensity shows that the laser cladding coating surface was smooth without rotating magnetic field. under the same laser cladding technical parameters, the Ni60CuMoW coating shows bad quality; the surface of Fe60coating shows gradually intensified waves, even appears fragmentation with increase of rotating magnetic field intensity. The XRD phase qualitative analysis shows that the different phase and the magnetic field intensity are irrelevant.The Fe60coating’s is composed ofγ(Fe,Ni)、 Fe23(C,B)6、and Cr5Si3by SEM and EDS further analysis research.The micro structure by OM shows that under the same laser cladding technical parameters, the hard phase structure of Ni60CuMoW coating tend to be lesser and uniform distribution, and the internal quality of Ni60CuMoW coating improves with increase of intensity of rotating magnetic field. Compared with no rotating magnetic field, the micro structure of hard phase in the Fe60coating tends to be lesser and uniform distribution under the same laser cladding technical parameters.Under the same laser cladding technical parameters, with increase of magnetic field intensity,compared with no rotating magnetic field, the micro-hardness of Fe60coating tends to be better in general, and the highest hardness is up to685HV0.5, microhardness increased by10.5%. The improvement of micro-hardness plays a beneficial role in increasing abrasion resistance of Q235steel.Compared with the coating without rotating magnetic field, the fractional abrasion loss weight of Fe60coating decreases gradually with increase of magnetic field intensity under the same laser cladding technical parameters,. When the rotating magnetic field intensity is255GS, the minimum fractional abrasion loss weight is fell33.8%to4.3mg. The performance of Friction and wear is improved.