The effect of carbon nanotubes on the corrosion and tribological behavior of electroless Ni-P-CNT composite coating

In this study, Ni-P-CNT composite coating was successfully deposited on the surface of copper by electroless plating. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) were used to characterize the coatings. The wear behavior of the coatings was investigated using a pin-on-disk test rig and subsequently friction coefficient data were reported. The corrosion behavior of the Ni-P and Ni-P-CNT coated specimen were evaluated through polarization curves and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl aqueous solution at the room temperature. The results indicated that the incorporation of carbon nanotubes (CNTs) in the coating improved both tribological behavior and corrosion resistance. These improvements have been attributed to superior mechanical properties, unique topological structure and high chemical stability of nanotubes.

► CNTs lead to an increase in nanocrystalline phase's fraction of Ni-P-CNT coating. ► CNTs increase hardness of both as-deposited and heat treated coatings. ► CNTs significantly improve tribological behavior of composite coating. ► Ni-P-CNT composite coating exhibit better corrosion behavior than Ni-P coating. ► CNTs could accelerate the chemical passivation of the Ni-P-CNT composite coating.