Dual-pulse gold plating process

Abstract

The invention relates to a dual-pulse cyanide-free gold plating process. The parameters of the dual-pulse plating are as follows: the frequency of positive pulse is 700-1,000Hz, the time is 50-100ms, the duty cycle is 10-20%, and the current density is 0.3-0.4; the frequency of negative pulse is 700-1,000Hz, the time is 20-80ms, the duty cycle is 5-10%, and the current density is 0.03-0.04A / dm<2>. By adopting the method, the obtained plating has the advantages of fine grain, uniform thickness distribution of the plating, low porosity, rare discoloration, high hardness and strong corrosion resistance.

Description

technical field [0001] The invention relates to a gold plating process, in particular to a double pulse electroplating gold process. Background technique [0002] Gold has high chemical stability and can only be dissolved in aqua regia, but not in other acids. The gold coating has strong corrosion resistance and good resistance to deformation. At the same time, the gold coating has a variety of colors, so it is widely used in plating jewelry, watch parts, artworks, etc. At the same time, gold has good electrical conductivity, easy welding, high temperature resistance, and certain wear resistance. Therefore, the gold-plated layer is widely used in precision instruments, printed circuit boards, integrated circuits and other parts that require long-term stable electrical parameters. So far, cyanide gold plating is mainly used in domestic and foreign gold plating processes. This is because the cyanide gold plating solution has good chemical stability, good dispersion and depth...

AI Technical Summary

Problems solved by technology

[0004] But these cyanide-free gold-plating solutions are compared with cyanide gold-plating solution, have the following disadvantages: (1) plating solution stability problem, all there is plating solution instability in a lot of cyanide-free gold-plating solutions, no matter it is alkaline cyanide-free gold-plating solution , Neutral cyanide-free gold plating solution, or acid cyanide-free gold plating solution, which brings inconvenience to managers

For example, sulfurous acid gold plating solution, thiosulfuric acid gold plating solution, etc., all contain sulfite ions, which are easily oxidized by oxygen in the air, so the service life of the gold plating solution becomes shorter, and nitrogen protection is required to prevent the gold plating solution from being oxidized. Inconvenience to operation and management

(2) The cost of plating solution is higher

[0006] However, the anti-corrosion performance, internal stress, toughness and wear resistance of the coating provided by the above electroplating method cannot fully meet the requirements of actual use.

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