Characterization and Wear Behaviors of Electrodeposited Ni-MoS2/SiC Composite Coating

Abstract

Among the preparation methods of functional coatings, the electrodeposition technique has attracted much attention due to its advantages of economy, high efficiency and good structural adaptability. The application of aluminum alloy materials is greatly limited due to their poor friction reduction and wear resistance. Therefore, to enhance the tribological behaviors of aluminum alloy materials, the Ni-MoS2, Ni-SiC and Ni-MoS2/SiC composite coatings were prepared on the 2218 aluminum alloy by an electrodeposition technique. The prepared composite coating samples exhibited a compact and dense microstructure, which was consistent with the result of their high microhardness. No obvious microcracks and defects appeared at the interfaces, indicating that the composite coating samples had good adhesion to the substrates and can effectively improve the frictional shear resistance. The results of wear experiment showed that the wear rate, friction coefficient and friction response time of all composite coating samples were lower than that of the substrate sample. However, the friction reduction and wear resistance of the same composite coating sample were not consistent. The friction coefficient of the Ni-MoS2 composite coating sample was the lowest, and the wear rate of the Ni-SiC composite coating sample was the lowest. According to the worn surface observations, the wear mechanism of composite coating samples was mainly characterized by the mild abrasive wear, flake spalling, tearing and pits caused by particle shedding, and the substrate sample showed a severe adhesive wear and abrasive wear.