Method for direct copper non-cyanide plating of zinc alloy casting die

Abstract

The invention discloses a copper plating method of zinc alloy casting piece, which comprises the following steps: a. electrolyzing cathode to remove oil; b. activating through washing by organic acid; c. immersing in the organic acid; d. plating copper directly with bivalent copper ion density at 10-25g / L and complexing agent density at 120-350 g / L, potassium carbonate density at 10-50g / L and hydroperoxide density at 1-15mL / L; maintaining pH value between 9 and 12; adjusting pH value through 50% potassium hydroxide solution; setting the current density of cathode 0.5-2.5A / dm2 at 20-50 deg.c.

Description

technical field [0001] The invention relates to a method for electroplating copper. Specifically relates to a method for direct cyanide-free electroplating copper on zinc alloy die castings, which can be used for direct copper preplating of zinc alloy die castings and thickening of electroplated copper layers. Background technique [0002] Zinc alloy has good casting properties and is an excellent casting alloy. It is more superior when used to cast workpieces with complex shapes and high precision. Zinc alloy die castings are increasingly used in automobiles, electronics, aerospace and other fields. However, cast zinc alloys are not wear-resistant and are easily corroded by humid atmospheres. In order to overcome the above shortcomings, zinc alloys are usually electroplated with single metals or alloys to improve their performance. The electroplated copper coating has the advantages of compactness, brightness, and good ductility. It is generally used as the bottom layer of...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for direct cyanide-free electroplating of zinc alloy die-castings in order to solve the problems of poor bonding force and complex process of the copper coating. Organic pickling activation → c. Organic acid impregnation → d. Direct copper plating; the composition and process conditions of the degreasing liquid of "a. Cathodic electrolytic degreasing" are: trisodium phosphate 10 ~ 40g / L, potassium sulfate 5 ~15g / L, sodium carbonate 10~30g / L, OS-10 (Pingpingjia series) 0.5~5g / L, pH value≤12, cathode current density D k =3~8A / dm 2 , time 2~5 minutes, temperature is room temperature; The composition and technological conditions of described " b.organic pickling activation " pickling solution are: hydrochloric acid 10~40g / L, organic acid 5~40g / L, temperature is room temperature , the activation time is 3-30 seconds; the composition and process conditions of the "c. organic acid impregnation" solution are: organic acid 30-80g / L, the temperature is room temperature, and the impregnation time is 1-10 seconds; the "d The composition and process conditions of the "direct copper plating" solution are: divalent copper ion concentration 10-25g / L, complexing agent 120-350g / L, potassium carbonate 10-50g / L, hydrogen peroxide 1-15mL / L, pH Keep it between 9 and 12, use 50% potassium hydroxide solution to adjust the pH value, and the cathode current density D k =0.5~2.5A / dm 2 , temperature 20~50℃