Method and solution for electrogalvanizing surface of zinc alloy workpiece comprising blind hole

Abstract

The invention discloses a method and solution for electrogalvanizing the surface of a zinc alloy workpiece comprising a blind hole. The method orderly comprises the steps of cleaning, activating, electrogalvanizing, reactivating and passivating the surface of the zinc alloy workpiece. The electrogalvanizing solution is characterized in that: the solution contains the following components per liter: 0.5 to 2 g of acridine, 0.05 to 0.2 g of dioctyl sodium sulfosuccinate, and the balance of common acidic galvanizing components. The electrogalvanizing solution adjusts the pH value to between 5.0 and 6.0 when the electrogalvanizing is performed, the temperature of the solution is kept between 20 and 30 DEG C, and the cathode current density is between 1 and 3 A / dm<3>. The method and the solution have the advantages that: the electrogalvanizing solution has little corrosion to the matrix of a zinc alloy after a corrosion inhibitor is added; and the throwing power of the blind hole is high after a wetting agent is added into the electrogalvanizing solution; a finally obtained electrogalvanized layer has good binding force, good the throwing power, and good compactness and corrosion resistance; and the efficiency is improved.

Description

technical field [0001] The invention relates to a solution and a method for electrogalvanizing the surface of a zinc alloy workpiece containing blind holes, and belongs to the field of material surface treatment. Background technique [0002] Due to its cheap price, low melting point, and especially good die-casting process performance, zinc alloy has been widely used in the manufacture of small hardware accessories. Some zinc alloy workpieces contain small-sized blind holes, which take a long time to process, and some wetting agents need to be added during the process. Moreover, the appearance of zinc alloy die castings is gray and white, and there are various defects on the surface, such as: ash, shrinkage cavities, etc. Therefore, without surface treatment, its usability and decoration are very poor. A common surface treatment method is electroplating. However, zinc alloys are relatively lively and have poor corrosion resistance, especially in acidic solutions. For exam...

AI Technical Summary

Problems solved by technology

However, zinc alloys are relatively lively and have poor corrosion resistance, especially in acidic solutions. For example, in the electroplating process, due to the long plating time, some corrosion inhibitors need to be added to prevent over-corrosion of zinc alloys, reduce costs, and improve efficiency.

[0003] Patent application number 200610151222.9 of the Chinese patent "A method for direct cyanide-free copper plating of zinc alloy die castings" discloses a zinc alloy die casting electroplating method, a. cathodic electrolytic degreasing → b. organic pickling activation → c. Organic acid immersion → d. direct electroplating copper; the composition and process conditions of the solution of "d. direct electroplating copper" are: divalent copper ion concentration 10 ~ 25g / L, complexing agent 120 ~ 350g / L, carbonic acid Potassium 10-50g / L, hydrogen peroxide 1-15mL / L, pH value maintained between 9-12, use 50% potassium hydroxide solution to adjust pH value, cathode current density D k =0.5~2.5A / dm 2 , temperature 20-50°C, this invention can be used for direct copper pre-plating of zinc alloy die-casting parts, and can also be used for thickening of electroplated copper layer. Galvanized on the workpiece surface