Galvanizing molten pieces by electrodeposition, comprises immersing pieces in first galvanizing bath, passing current between pieces and zinc anodes immersed in first galvanizing bath, and rinsing treated pieces in first galvanizing bath

摘要

The process of galvanizing molten pieces by electrodeposition, comprises immersing the pieces to be treated, which acts as cathode in a first galvanizing bath with an acidic pH and in aqueous solution containing 100-400 g/l of potassium chloride, 10-150 g/l of zinc chloride and 20-80 g/l of boric acid, passing current between the pieces and zinc anodes immersed in the first galvanizing bath, rinsing the treated pieces in the first galvanizing bath, and immersing the pieces in a second galvanizing bath with an acidic pH and in aqueous solution. The process of galvanizing molten pieces by electrodeposition, comprises immersing the pieces to be treated, which acts as cathode in a first galvanizing bath with an acidic pH and in aqueous solution containing 100-400 g/l of potassium chloride, 10-150 g/l of zinc chloride and 20-80 g/l of boric acid, passing current between the pieces and zinc anodes immersed in the first galvanizing bath, rinsing the treated pieces in the first galvanizing bath, and immersing the pieces in a second galvanizing bath with an acidic pH and in aqueous solution containing 150-400 g/l of potassium chloride, 50-100 g/l of zinc chloride and 100-300 g/l of nickel chloride and 40-80 g/l of boric acid, and passing the current between the pieces and zinc anodes immersed in the second galvanizing bath. The first galvanizing bath contains 10-50 ml/l of a penetration base and 1-4 ml/l of brightening agents. The second galvanizing bath contains 0.5-500 ml/l of brightening and leveling additives. During the first step of galvanization, the first galvanizing bath is maintained at a temperature of 20-50[deg] C. During the second step of galvanization the second galvanizing bath is maintained at a temperature of 30-50[deg] C. The first step of galvanization is carried out under a cathodic current density of 1-5 A/dm 2, and the second step of galvanization is carried out under a cathodic current density of 1 A/dm 2. The pieces to be treated are rinsed in the second galvanizing bath and then subjected to passivation step.