Method of in situ plating of an active coating on cathodes of alkali halide electrolysis cells

摘要

An active metal coating which lowers the hydrogen discharge overpotential at the cathode in the electrolysis of aqueous alkali metal halide solutions is deposited on the cathode tubes of a cathode can of an electrolysis cell without the removal of the tubes from the can. Plating solution and anodes of plating metal are placed inside a cathode can and the components are electrically connected so as to deposit an active coating onto the cathode tubes. The plating metal is preferably an alloy of nickel and zinc and the process involves the final step of leaching the zinc component of the alloy deposit from the plated cathode tubes to provide a porous, active nickel surface which results in a reduction of the hydrogen discharge overpotential for the electrolysis of alkali metal halides, particularly sodium chloride.