Pretreating workpiece in an electrophoretic dip enameling process activating bath

摘要

In an electrophoretic dip enameling process activating bath, copper is present in hydrated ionic form in a concentration of not more than 50 mg/l and copper dissolution and deposition equilibrium is maintained. In a method of pretreating a workpiece in an electrophoretic dip enameling process activating bath which is positioned between a degreasing bath and the enameling bath and which contains added copper and acid, the copper is converted into hydrated ionic form in the activating bath and chemical and dynamic equilibrium is maintained between copper dissolution and deposition in the bath, the copper concentration being not more than 50 mg/l.