Electroless and electrolytic deposition of nickel from deep eutectic solvents based on choline chloride

摘要

The electroless and electrolytic deposition of nickel from a solution containing nickel chloride in either an ethylene glycol (EG)-choline chloride based or a urea-choline chloride based ionic liquids has been carried out onto copper and steel cathodes under different conditions. It is found that electroless nickel deposits of up to several microns has been obtained by dip coating from only EG based ionic liquids at temperature above 70°C without the use of catalysts. The influences of various experimental conditions on electrodeposition and the morphology of the deposited layers have been investigated by scanning electron microscopy and X-ray diffraction. It is shown that very smooth, shiny and dense with good adherence and bright metallic coloured nickel coatings can be obtained from both EG and urea-based ionic liquids at applied deposition potential of up to -0.50 V and applied deposition current density of up to -5.0 A m~(-2) between 50°C and 100°C. The eathodic current efficiency for the deposition of Ni is about 97%.