Investigation of Ni-Mo and Co-Mo alloys electrodeposition involving choline chloride based ionic liquids

The paper presents several experimental results regarding the electrodeposition of Ni-Mo and Co-Mo alloy coatings from choline chloride based ionic liquids, applied onto Cu metallic substrates. Electrolytes containing Ni2+, Co2+ and Mo6+ salts in choline chloride - urea - citric acid ternary mixtures have been taken into consideration. The electrodeposited Ni-Mo and Co-Mo alloy coatings were adherent and uniform onto Cu metallic substrate. Ni-Mo alloys containing 2-35 wt. % Mo and Co-Mo alloys with 6-63 wt. % Mo have been obtained, depending on the metallic ions mass ratio and on the value of current density. As SEM analysis revealed, the operating parameters significantly influence the surface morphology of the obtained alloy coatings. According to XRD analysis, both electrochemical alloy coatings showed a nanocrystalline structure, having crystallites average sizes in the range of 3-7 nm. The alloy coatings corrosion performance has also been discussed. (C) 2016 Elsevier Ltd. All rights reserved.