Study On Ni - Based Wear Resistant Composite Coating By Semiconductor Laser Cladding

The titanium alloy has high strength,good corrosion resistance,good oxidation resistance and high temperature performance.The titanium alloy which is widely used in various fields of the aerospace, chemical oil, biological medicine, etc.However, the low titanium alloy surface hardness, high temperature oxidation resistance, poor wear-resisting performance poor and difficult to lubrication,which have largely restrict the exertion of its potential.Using the appropriate surface modification technology can effectively improve its wear resistance in titanium alloy surface.Adopting the surface modification technology in the preparation of the coating on titanium alloy surface, in most cases, the wear resistance of the improvement is to enhance the surface hardness and strength, which friction coefficient and friction compatibility is not good to improve.Therefore, having certain self lubrication in the process of friction movement that become a research hotspot in material field.At present, duing to their high energy density of laser cladding, the characteristics of cooling speed, the coating density, small grains, metallurgical bonding with base,Therefore, laser cladding technology is the effective means of the preparation of wear-resistant self-lubricating coatings.In this paper, adopts the semiconductor laser on TC4 alloy matrix could achieve the Ni-base wear-resisting antifriction composite coating with good metallurgical combination preparation by NiCrBSi, WS2 powders as the raw material.The influence of process parameters on the microstructure and properties, revealing the wear mechanism and the lubrication mechanism of the Ni-based alloy coatings, were systematically investigated by optical microscopy, X-ray diffraction, scanning electron microscopy, electron probe micro-analyzer, Vickers hardness tester, and friction wear testing machine.And through the electrochemical corrosion experiment, this paper analyzes the corrosion resistance of coating.By studying the influence of the macro-surface cladding layer of laser process parameters on, revealing the geometry size of the cladding layers and dilution rate change rule, to optimize the laser processing parameters laid a theoretical foundation.The results show that,Cladding layer and substrate to form a good metallurgical combination;The main phase of the Ni60 laser cladding is TiC and TiB2, γ-Ni,The Laser coating containing WS2 main object contains Ti2CS, TiB2, TiS, CrxSy, γ-Ni, Cr2B,{Ni, W};Theaverage hardness of the cladding layer of Adding the solid lubricant WS2 were lower than average hardness of the Ni60 cladding layer(1000～1200 HV0.3),With the increase of content of WS2, cladding layer showed a trend of decrease of the average hardness;The friction coefficient of adding WS2 cladding layers are smaller than the Ni60 coating layer,and Wearing is about 2.5 times,which shows the wear resistance of cladding layer increases greatly after adding WS2;According to the polarization curve,With the increase of content of WS2, corrosion potential, the more is to want to move, the smaller the corrosion current density, so the corrosion rate is reduced, so the stronger ability to resist corrosion.