Sliding wear behavior of nanocrystalline nickel coatings: Influence of grain size

In the present study the sliding wear behavior of pulse electrodeposited nanocrystalline Ni coatings as a function of grain size including bulk annealed Ni has been systematically studied using pin-on-disc configuration against the WC-Co counter body. The sliding wear has been analyzed with respect to wear rate, coefficient of friction, subsurface deformation and composition of wear debris. The result indicates that the sliding wear rate and coefficient of friction of Ni decreases with decreasing grain size. The subsurface beneath the worn pin surface is composed of a near surface shear region and beneath it a region of bulk plastic deformation. The ratio of the depth of the shear region to the depth of bulk deformed region decreases with decreasing grain size indicating a greater localization of near surface deformation with decreasing grain size.