Electroplating liquid for watch shell

Abstract

The invention discloses electroplating liquid for a watch shell. The electroplating liquid comprises the following components: 45-49 g / L of tin methanesulfonate, 35-39 g / L of copper pyrophosphate, 210-220 g / L of potassium pyrophosphate, 43-47 g / L of calcium chloride, 32-34 g / L of tin chloride, 15-25 g / L of disodium hydrogen phosphate, 6-8 mL / L of polyethylene glycol, 3-5 mL / L of polyethylene glycol alkyl alcohol ether, and 4-6 mL / L of gelatin.

Description

technical field [0001] The invention relates to the technical field of electroplating, in particular to an electroplating solution for watch casings. Background technique [0002] The surface of the watch case is usually electroplated with a decorative coating to form a shiny surface, which plays a decorative or protective role. The early decorative coatings are usually nickel or chromium coatings, and this coating is prone to discoloration and yellowing in the aerobic ring mirror, which affects the appearance; moreover, the electroplating solution that forms the above coatings usually contains cyanide, and cyanide is poisonous. It is beneficial to the health of process workers, but not conducive to environmental protection; moreover, nickel often causes skin allergies, so it is not suitable to use nickel plating for watches that often come into contact with human skin. [0003] For this reason, at present, some operators use the copper-tin alloy coating as the decorative c...

AI Technical Summary

Problems solved by technology

The copper-tin alloy coating is usually cupronickel tin, although it does not contain nickel and will not cause skin allergies, but the electroplating solution also contains heavy metals such as cyanide or lead to help electroplating, which is not conducive to environmental protection

Not only that, but this kind of coating also has the following disadvantages: first, the ratio of the above-mentioned copper-tin alloy coating is that the ratio of copper is higher than that of tin, usually copper≥70%, tin≤30%, and its thermal stability is poor. It is easy to turn yellow and affect the aesthetic appearance, so it is necessary to electroplate a color coating on the copper-tin alloy coating, such as tin-cobalt coating, trivalent chromium or precious metal coating (such as palladium coating, gold coating, rhodium coating and palladium-copper alloy coating) , its role is to increase its corrosion resistance and aesthetics; secondly, the electroplating solution that forms the above-mentioned copper-tin alloy coating contains stannous pyrophosphate, which is divalent tin. During the electrolysis process, due to O in the air 2 or the reason of anodic oxidation in electroplating, which converts divalent tin into tetravalent tin, which leads to the accumulation of tetravalent tin, which makes the performance of the electroplating layer poor, which in turn shortens the service life and the surface brightness of the coating will also be poor , will turn black and produce fog