Cyanide-free alkaline copper plating electroplating solution for zinc alloy die castings and preparation method and electroplating method thereof

Abstract

The invention discloses a cyanide-free alkaline copper plating electroplating solution for zinc alloy die castings and a preparation method and an electroplating method thereof. The cyanide-free alkaline copper plating electroplating solution is prepared from the following components of 5-50g / L of main salt, 5-30g / L of a compound adsorbent and 200-400g / L of a complexing composition. By adding the compound adsorbent to change the copper ion concentration in a double electrode layer on a cathode surface, the cathode interface copper ion potential can be effectively reduced, the copper ion discharging precipitation is inhibited, the 'zinc-copper replacement reaction' is completely inhibited in the alkaline plating solution, the complexing effect with the complexing composition is synergistic, the effect that 1 + 1 is greater than 2 is generated, the copper ion concentration in the double electrode layer is changed, and the copper ion potential is effectively reduced, so that copper ion discharging is more difficult; the 'zinc-copper replacement reaction' is completely inhibited in the alkaline plating solution, the technical problems that cyanide-free copper plating binding force of the zinc alloy die castings is poor and bubbling is prone to occurring are solved, and plating layers are bright and fine in crystal and firm in binding force.

Description

technical field

[0001] The invention belongs to the technical field of electroplating, and in particular relates to a cyanide-free alkaline copper plating electroplating solution for zinc alloy die castings, a preparation method thereof and an electroplating method. Background technique

[0002] Zinc alloy die castings are amphoteric metals, the electrode potential is relatively negative, often contains about 3% aluminum, and the chemical stability is poor. In the pretreatment process, zinc dipping treatment is not carried out, the driving force of the displacement reaction is large and it is difficult to suppress, and the requirements for the cyanide-free copper plating process are higher, which has become the biggest bottleneck in the electroplating industry to completely replace the cyanide copper plating. In order to obtain a good coating bonding force, the direct copper plating on zinc alloy die castings at home and abroad is currently using an alkaline and highly toxic...

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