| By adding nanoparticles in jet electrodeposition,co-deposition with the metal base can form a composite coating with high microhardness and excellent performance.However,the size of the nanoparticles is small,the surface energy is high.The nanoparticles are easily attracted to each other,thereby reducing their surface energy and cause agglomerations.The agglomerated nanoparticles are not easy to deposit on the composite coating,and the coating quality is poor.In order to solve the above-mentioned agglomeration,it is necessary to add a dispersant that matches the nanoparticles in the composite plating solution at the same time to achieve the purpose of inhibiting agglomeration and enhancing dispersion.Graphene nanosheets(GNSs)can change the surface charge distribution of nanoparticles in the composite plating solution,thereby inhibiting particle agglomeration and enhancing dispersion.At present,researches mostly focus on the effect of adding nanoparticles on the performance of composite coatings prepared by jet electrodeposition,and there are few studies on adding dispersants to inhibit the agglomeration of nanoparticles and give full play to nanoparticles to improve the performance of composite coatings.Based on the above analysis,this paper selects graphene nanosheets as a new type of dispersant.The Ni-P-WCGNSs composite coatings are prepared by jet electrodeposition,and the effect of different GNSs concentration,current density and scan time on the performance of the Ni-P-WCGNSs composite coating are explored.The main research contents are as follows:(1)Based on the device and process parameters of jet electrodeposition,the process test plan for the jet electrodeposition preparation of composite coatings was proposed,the characterization process of graphene nanosheets and composite plating solutions was formulated,and the basic principles and operating procedures of performance testing equipments such as scanning electron microscope,X-ray diffraction,EDS energy spectrum analyzer,CNC wire-cutting machine and metallographic sample mounting machine were introduced;(2)The three-factor three-level orthogonal experiment table of GNSs concentration,current density and scan time was designed,the process test of Ni-P-WC-GNSs composite coating prepared by jet electrodeposition was carried out,and the effect of different process parameters on the surface morphology of composite coating,cross-section morphology of composite coating,coating thickness,EDS element composition and content,XRD phase analysis and element penetration zone was explored.Clarified the deposition mechanism,graphene nanosheet dispersion mechanism and element penetration mechanism;(3)A composite coating microhardness test based on a microhardness tester was carried out.Five groups of microhardness values were randomly measured and the average value was taken as the average microhardness of the composite coating.The effect of different process parameters on the microhardness of the composite coating was studied.The friction test based on the material surface comprehensive performance tester was carried out,and the size and surface morphology of the wear scar were obtained by laser confocal microscope and scanning electron microscope,and the influence of different process parameters on the wear resistance of the composite coating was explored;(4)The electrochemical corrosion test of the composite coating based on the CS350 electrochemical workstation was carried out.The electrochemical test method of the threeelectrode system was used to test the potential polarization curve and electrochemical impedance test of the composite coating.Corr Test software was used to analyze the corrosion current density,corrosion potential and charge transfer resistance,the surface morphology of the composite coating after corrosion was obtained by scanning electron microscope,and the influence of GNSs concentration,current density and scan time on the corrosion resistance of the composite coating was explored. |
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