Cathode Growth at the Air-solution Interface in the Electrodeposition of Copper

Abstract

WE wish to report an unusual growth of cathode deposit along the air-solution interface during electrodeposition of copper from an acid sulphate electrolyte containing small amounts of norvaline. Electrolysis was carried out in a simple glass cell containing a vertical copper wire cathode about 1 mm in diameter surrounded by a cylindrical copper anode of 3.2 cm inside diameter. The aqueous electrolyte contained 0.5 M CuSO₄ and 1.0 M H₂SO₄. The temperature was 25° ± 0.05° C and the current was held constant at a value such that the initial current density was about 0.030 A cm⁻² with about 4.5 cm of the cathode immersed. The solution was not stirred during electrolysis. In these conditions, optimum growth of the deposit along the air-solution interface occurred when 0.025 M norvaline was added.