Non electrolytic nickeling manner null of spelter or spelter

摘要

PURPOSE:To form an electroless Ni plating excellent in adhesion on a Zn material to be plated by treating the material with an aq. alkaline soln. contg. Ni and Cu ions to form a substituted film and then plating the material in an electroless Ni plating bath. CONSTITUTION:A material to be plated consisting of Zn or its alloy is treated with an aq. alkaline soln. contg. Ni and Cu ions to form a substituted film. NiSO4, etc., are used as the Ni ion source and CuSO4, etc., as the Cu ion source. Zu ion is incorporated, as required, into the substitution soln. using ZnSO4, etc., and further a complexing agent for the metal ion in the substitution soln. such as NH3, EDTA can be added. The substitution reaction is preferably carried out by dipping the material in the soln. at room temp. for about 1-10 min. The material coated with the substituted film is electroless-Ni-plated preferably in an alkaline medium. When the film thickness has to be increased, the material is further electroless-Ni-plated at a high rate in an acidic medium.