Ni and Ni alloy coatings electrodeposited from choline chloride-based ionic liquids-electrochemical synthesis and characterization

This study deals with some preliminary experimental results regarding the electrodeposition and characterization of Ni and Ni alloy coatings, respectively, NiMo and NiSn, from some choline chloride‐based ionic liquids. The obtained Ni deposits are adherent, uniform onto Cu substrate. According to X‐ray diffraction investigations, average sizes of the crystallites have been in the range of 9.2–14.4 nm, higher for increased applied current densities, maybe as a result of the increase in temperature during electrodeposition. In addition, an amorphous phase was evidenced. NiMo alloy coatings have been obtained for the first time from ionic liquids containing 0.42 M NiCl2·6H20 and 0.016 M ammonium heptamolybdate in choline chloride‐urea‐citric acid or chloline chloride–ethylene glycol–citric acid mixtures. NiSn alloys were formed in choline chloride–urea and choline chloride–ethylene glycol solvents, with various additions of Ni and Sn salts. The obtained alloy deposits are adherent, uniform onto Cu substrate. To obtain information on the deposits' morphology and composition, atomic force microscopy, SEM and energy‐dispersive X‐ray techniques were used and the results are discussed taking into account the ionic liquid type, composition and conductivity in close correlation with electrochemical conditions. Copyright © 2010 John Wiley & Sons, Ltd.