The effects of pulse–reverse parameters on the properties of Ni–carbon nanotubes composite coatings

A nickel based composite coatings reinforced with carbon nanotubes (CNTs) were prepared by pulse–reverse electrodeposition. The effects of reverse ratio and frequency on the surface morphology, micro-hardness and corrosion resistance of Ni–CNTs composite coatings were studied. The results showed that higher pulse reverse ratio and pulse frequency made the surface morphology of the coatings more homogeneous. The micro-hardness of the coatings increased with the increase of reverse pulse ratio but decreased with the increase of pulse frequency. Corrosion resistance of the coatings first increases then decreases as the pulse frequency and reverse ratio increase. The best corrosion resistance was obtained for coatings under the condition of 30% reverse ratio and 100 Hz pulse frequency. The effects of CNTs on the properties of the composite coatings were discussed.