Electrodeposition of nickel from solutions containing liquid crystals

The possibility of obtaining structured nickel coatings by chemical and electrochemical deposition was investigated. Deposition was performed from electrolytes containing liquid crystals. The electrolytes were prepared from a saturated (aqueous or ammoniac) solution of nickel chloride and nonionic surfactant OP-10 at a weight ratio of solutions 1:1. The chemical deposition of nickel was performed on aluminium substrate, and electrochemical deposition was performed on nickel, copper and titanium substrates. Deposition on aluminum and nickel was performed from electrolyte composed of a saturated aqueous solution of nickel chloride and OP-10. During the deposition on copper and titanium the aqueous solution of nickel chloride was replaced by ammoniac one. The purpose of the replacement was to increase the pH of the solution and, as a consequence, to decrease the hydrogen evolution and increase output of nickel. Studies of the coatings by scanning electron microscope showed that in the case of deposition of nickel from aqueous solution coating contains mainly nickel hydroxochloride. When replacing a water solution by ammoniac, the precipitated coating comprises nickel metal in the form of dendrites with a size from 50 to 1000 nm.