Deposition and characterization of nanocrystalline and amorphous Ni-W coatings with embedded alumina nanoparticles

Nanocrystalline and amorphous Ni-W coatings containing Al2O3 nanoparticles were electrodeposited from three different ammoniacal citrate baths by direct current (DC) method. The effects of nanoparticles on compositional, structural and morphological features of Ni-W coatings were investigated. The effects of bath chemical composition and current density on codeposition behavior of nanoparticles were also studied. Guglielmi model for particle deposition was applied to identify the kinetics of particle deposition. The presence of nanoparticles may affect on coating grain size, tungsten content and the rate of metal deposition. In addition, nanoparticles can result in more compact coatings with fewer defects. The extent of these effects depends on bath chemical composition and may be influenced by the synergistic effect of Ni on deposition of W. It was also found that the kinetics of particle deposition and the effect of current density on codeposition behavior of nanoparticles are highly dependent on bath chemical composition. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.