Study On Preparation And Mechanism Of Graphene-reinforced Metal Matrix Composite Coatings

As a unique carbon nanostructure,graphene can be added to the material as an augmented body to improve properties.It can not only improve physical and chemical properties of the surface,but also reduce the cost,which is also important for expanding the application field of graphene.The purpose of this project is to prepare graphene/ metal matrix composite coating by laser cladding and electrodeposition technology,and explore the best process of graphene/ cobalt based coating,graphene/Fe-W-Cu coating and graphene oxide/Fe-W-Cu coating.Microstructure of surface and cross section of the coating was observed by optical microscope,scanning electron microscope and the EDS.The phase structure and grain size of the coatings were analyzed by XRD analysis,and characterization of graphene oxide was used by Raman spectroscopy.Mechanical properties,tribological properties and electrochemical properties of the composite coatings were analyzed.The influence of graphene as the addition of the relative coating and its mechanism of action are explored.The addition of graphene or graphene oxide can provide nucleation sites and grain refinement to some extent,and improve the mechanical properties,tribological properties and electrochemical properties of coatings.The experimental results show that the preparation of graphene/ cobalt based composite coating of the best cladding parameters for laser cladding system is: laser power 1500 W,scanning speed of 30mm/s.Graphene is evenly distributed in the coating.The graphene/ cobalt based composite coatings with 0.4 wt.% graphene performs the best coating hardness.The coating with 0.8 wt.% graphene performs the best wear resistance.Adding 0.2 wt.% graphene composite coating shows the best corrosion resistance.Graphene /Fe-W-Cu composite coating prepared by electro brush plating,graphene evenly distributed in the coating,the density of the coatings was increased with graphene adding.Coating with 0.2g/L graphene shows the minimum grain size and the highest hardness,the best tribological properties.Graphene oxide in graphene oxide/ Fe-W-Cu composite coating prepared by electro brush plating is evenly distributed in the coating;the graphene oxide is reduced in the brush plating process.The denser microstructure is obtained when the graphene oxide added 0.2 g/L,the minimum grain size,and the highest hardness.Composite coating with the addition of 0.6g/L graphene oxide shows the best tribological properties of coatings.