Comparison between the microstructural, morphological, mechanical and tribological characteristics of nanocrystalline Ni and Ni-Co electrodeposited coatings

Abstract EN

For improving the wear resistance of steel used commonly in industry, nanocrystalline nickel and nickel-cobalt coatings are electrodeposited on A60 steel substrate in a modified Watts bath.

The observation of the coatings produced by scanning electron microscopy (SEM) shows that nickel coatings have a smooth morphology whereas Ni-Co alloy deposits have a lens-shaped morphology with a considerable increase in the grains size of Ni-Co alloy deposits.

The results of XRD show that nickel coatings having fcc phase structure while Ni-Co coatings have hcp phase structure.

The study of coatings micro-hardness indicates that the latter follows Hall Petche effect where nickel deposits which have the smallest grain size show a higher micro-hardness in comparison with Ni-Co coatings.

Pin on disk tribometric analysis under unlubricated conditions illustrates a great improvement of the wear resistance by the addition of cobalt on nickel coatings, where the friction coefficient and the wear rates are significantly reduced in Ni-Co coatings compared with nickel coatings.