Electrophoretic‐Deposition of Graphene and Microstructure and Friction Behavior of Ni–Graphene Composite Coatings

Ni–graphene composite coatings with promising friction reduction and wear resistance are successfully deposited on magnesium alloys substrate by an integrative approach involved electrophoresis and pulse electrodeposition. The optimization parameters for electrophoretic deposition are explored extensively. The effect of duty cycle on microstructure, micro‐indentation hardness, friction, and tribological properties for Ni–graphene composite coatings are investigated. The Ni matrix exhibits most refined at 60% duty cycle according to surface micrographs of the Ni–graphene composite coatings. The cross‐section microstructure and line energy spectra proves that the Ni–graphene coating is deposited on the substrates successfully and is physically bonded to the substrates. The peak value of micro‐indentation hardness about 181.78 HV at 60% is achieved. The lowest friction coefficient and minimal wear loss of Ni–graphene composite coatings are obtained at 60% duty cycle, indicating optimal friction reduction and wear resistance performance. The picture (a) shows a novel type of Ni–graphene composite coatings prepared by electrophoresis and pulse electro‐deposition successfully. The wrinkled graphene sheets are well incorporated into nickel metal matrix. The most superior anti wear performance of Ni–graphene coatings is achieved at 50% duty cycle with lowest friction coefficient, wear loss and narrowest worn scar as shown in (b)–(d).