Combined plating solution for plating decorative chrome on zinc die-casting alloy piece

Abstract

The invention discloses a combined plating solution for plating decorative chrome on a zinc die-casting alloy piece. The plating solution comprises a cyanide-free copper preplating solution, an acid copper plating solution, a semi-bright nickel plating solution, a high-sulfur-nickel electroplating solution, a bright nickel electroplating solution and a chrome electroplating solution. The six plating solutions are prepared and stored independently. During using, firstly, the electroplating solution used for cyanide-free copper pre-electroplating is subjected to bottoming of cyanide-free copper electroplating; then, a transition layer is coated by using the acid copper plating solution, the semi-bright nickel plating solution, the high-sulfur-nickel electroplating solution and the bright nickel electroplating solution sequentially; and finally, the chrome electroplating solution is used for conducting surface decorative chrome plating.

Description

technical field [0001] The invention relates to the field of electroplating, in particular to a combined plating solution for plating decorative chrome on die-cast zinc alloy parts. 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, and can also be used to manufacture decorative and practical metal parts. Such as various zippers, belt buckles, luggage accessories, car nameplates and military badges, etc. [0003] The appearance of zinc alloy die castings is gray and white, and there are various defects on the surface, such as: slag inclusions, shrinkage cavities, etc. Therefore, without surface treatment, its usability and decoration are very poor. A common surface treatment method is electroplating. According to the different decorative and functional requirements, there are certain differences in the electroplating p...

AI Technical Summary

Problems solved by technology

[0006] Neutral nickel pre-plating is mainly used for the rack plating process of zinc alloy die castings, and the main component of the plating solution is NiSO 4 , sodium citrate, etc., do not contain cyanide, but the bonding force between the nickel plating layer and the substrate is far inferior to the performance of cyanide copper plating pre-plating, and the product qualification rate is low

Moreover, due to the poor activation ability of the neutral nickel plating solution on zinc alloy die castings, there are higher requirements for its pretreatment

The neutral nickel plating process generally cannot be used for barrel plating of zinc alloy die castings, therefore, the range of industrial applications is not very wide

In addition, the cost of neutral nickel plating solution is high, and wastewater treatment is difficult, which limits its large-scale application in industry.

[0007] Other zinc alloy die casting pre-plating processes include chemical copper plating, HEDP copper plating, copper-tin alloy electroplating, etc., all of which have not been practically applied in industry due to problems such as bonding force, cost, and wastewater treatment.