Superior corrosion and wear resistance of AZ91D Mg alloy via electrodeposited SiO2–Ni-based composite coating

Abstract

Improving the poor corrosion resistance and high wear defects of AZ91D Mg alloy by electroplating coating could be of importance to enhance its industrial applications. In this paper, we propose a method for constructing micro-nano structures by electrodeposition of SiO2–Ni-based composite coatings on AZ91D Mg alloy. Meanwhile, we systematically compared the effects of different SiO2 doping amounts on the properties of SiO2–Ni-based coating. The AFM and SEM results showed that as-prepared composite coating with 10 g/L SiO2 doping had relatively largest roughness and the most micro-nano structures. By the analysis of XRD, the grain size of SiO2–Ni-based composite coating was lower than the pure nickel coating. Mechanical and tribological results showed that the SiO2–Ni-based composite coating with 10 g/L SiO2 doping could exhibit the maximum micro-hardness, minimum friction coefficient and lowest specific wear rate. It exhibited excellent wear resistance than that of other coating. In addition, dynamic polarization potential and electrochemical impedance spectroscopy (EIS) tests analysis presented that composite coating could have excellent corrosion resistance compared to pure Ni coating. Consequently, AZ91D Mg alloy could achieve superior corrosion and wear resistance via electrodeposited SiO2–Ni-based composite coating, indicating it has a widely potential in the industrial applications.