| Thermal spraying technology is widely used in the surface protection of metal due to its high efficiency and cost performance nowadays.While at the same time,thermal spray coatings have some disadvantages such as high porosity,low coating density and low bonding strength with the substrate.The remelting treatment can significantly reduce the porosity of the coatings,make the stacked layer structure dense and enhance the bonding strength of the coatings and substrate,which will further make the thermal spray coatings more useful.Different remelting treatment methods and their process parameters have great influence on the performance of coatings.Therefore,this paper mainly explores the effects of different remelting processes on the microstructure and properties of flame spray coatings,and attempts to find the best process parameters for each remelting method through comparative experiment.In this paper,a flame sprayed nickel-based 625 alloy coating was prepared on a 20#carbon steel substrate,and three different remelting treatments were performed,which were flame remelting,laser remelting and induction remelting,respectively.Each remelting method uses different process parameters for experimentation.The phase composition of the coating was analyzed by X-ray diffraction.The microstructure and element distribution were analyzed by scanning electron microscopy and energy dispersive spectroscopy.The porosity of the coating was analyzed by the Image Pro graphics processing software.Then the microhardness and high temperature chloride salt corrosion experiments of the samples were carried out.The surface morphology and compositions of the corrosion products were analyzed by scanning electron microscopy and energy dispersive spectroscopy. |
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