Iranian Journal of Materials Science and Engineering

en COMPARISON OF ELECTRODEPOSITION ASPECTS AND CHARACTERISTICS OFNi-WAND Co-WALLOYNANOCRYSTALLINE COATINGS گروه سطح پوشش و خوردگی Surface Coatings and Corrosion Research Paper Research Paper Abstract: current densities. Electrochemical impedance spectroscopy (EIS) results showed that the codeposition mechanism oftungsten in Ni-W deposition is the reduction of tungsten oxide which changed to the reduction of tungsten-containingion complexes at higher current densities. In Co-W electrodeposition, the tungsten codeposition takes place viareduction of tungsten oxide, although, the role of tungsten-containing complexes at higher current densities cannot beruled out. The surface morphology of Ni-W coatings was crack-free and was strongly dependent on deposition currentdensity. In addition, higher grain size and lower tungsten content were obtained by increasing the current density. InCo-W coatings, no obvious variation in surface morphology was observed except for the fine cracks appeared athigher current densities. In this system the grain size remained almost constant with increasing current density. Themicrohardness values of Ni-W and Co-W coatings decreased due to the increase in the grain size and/or decrease intungsten content.Ni-W and Co-W alloy nanocrystalline coatings were electrodeposited on copper substrate at different Co-W; Ni-W; electrodeposition; EIS; nanocrystalline; coating 16 24 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-3-129&slc_lang=en&sid=1 Z. Ghaferi * ghaferi_z@yahoo.com 180031947532846001148 180031947532846001148 Yes K. Raeissi 180031947532846001149 180031947532846001149 No M. A. Golozar, 180031947532846001150 180031947532846001150 No A. Saatchi 180031947532846001151 180031947532846001151 No S. Kabi 180031947532846001152 180031947532846001152 No