A kind of preparation method of composite coordination low-concentration monovalent gold cyanide-free gold plating electroplating solution
A technology for cyanide-free gold plating and electroplating solution, which is applied in the field of electroplating, can solve the problems of complicated preparation process, affecting the conductivity of the coating layer, easy decomposition of sulfite radicals, etc., and achieves the effects of simple preparation process, improved stability and good binding force.
Active Publication Date: 2021-06-25
XIAMEN UNIV
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Problems solved by technology
The main problems of sulfite gold plating are: the sulfite is easy to decompose, and the plating solution is unstable
If the concentration of sodium sulfite is too high, it may lead to high viscosity of the plating solution and sulfur inclusion in the plating layer, which will affect the conductivity of the plating layer.
[0004] Chinese patent (CN 108441902 A) discloses a monovalent gold cyanide-free gold plating solution based on complex coordination of alkaloids, its main salt, sodium gold sulfite, precipitates chloroauric acid through ammonia water, filters and washes, and then dissolves it with sodium sulfite solution Precipitation and other steps of "Rekin method" preparation, the preparation process is complicated and tedious
In addition, the soft base complexing agent used is a sulfur-containing compound, which may lead to the inclusion of sulfur in the gold plating layer.
Method used
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Embodiment 1～3
[0039] A kind of composite coordination low-concentration monovalent gold cyanide-free gold-plating electroplating solution of embodiment 1~3, take configuration 1000mL as an example, according to the composition and dosage in Table 1, preparation method comprises the following steps:
[0040] (1) Add the main complexing agent, buffering agent, composite complexing agent I and complex complexing agent II listed in Table 1 in deionized water, stir and dissolve, adjust the pH to 20wt% sodium hydroxide or 20wt% sulfuric acid solution 9.0~10.5, get the first solution;
[0041] (2) adding chloroauric acid under stirring of the first solution to obtain the second solution;
[0042] (3) Add brightener and wetting agent in the second solution to obtain the third solution;
[0043] (4) Adjust the pH of the third solution to 8.0-11.5, add deionized water to 1000mL, and obtain the composite coordination low-concentration monovalent gold cyanide-free gold plating solution.
[0044] Usin...
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Abstract
The invention discloses a compound coordination low concentration monovalent gold cyanide-free gold plating solution and a preparation method. The pH of the electroplating solution is 8.0-11.5, and the stable, convenient and easy-to-buy chloroauric acid is directly used as the main salt source, and it also includes the main complexing agent, complex complexing agent Ⅰ, complex complexing agent Ⅱ, buffer, and brightener and wetting agents. The present invention adopts the composite coordination mode to assist the coordination of monovalent gold, which not only improves the stability of the monovalent gold cyanide-free gold plating solution and the stable discharge point interval, but also significantly reduces the concentration of sulfite in the plating solution, avoiding The inclusion of sulfur in the plating layer makes the obtained gold plating layer bright and golden in appearance and has good bonding force with the substrate, which is suitable for decorative gold plating; and the preparation process of the plating solution of the present invention is simple, the condition is mild, and the plating solution is stable.
Description
technical field [0001] The invention belongs to the technical field of electroplating, and in particular relates to a method for preparing a cyanide-free gold-plating electroplating solution for composite coordination low-concentration monovalent gold. Background technique [0002] The gold coating has excellent electrical conductivity and thermal conductivity, and good welding performance. It is widely used in the electronics industry as a functional coating. At the same time, the gold coating is elegant and noble golden yellow, and its alloy coating also presents a variety of K gold tones, and has strong corrosion resistance. Therefore, it is often used in precious decorations. At present, cyanide monovalent gold plating process is widely used in industrial production. Cyanide is highly toxic and threatens the safety of the environment, human body and society. The development of cyanide-free gold plating process to replace cyanide gold plating is one of the processes tha...
Claims
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IPC IPC(8): C25D3/48
CPCC25D3/48
Inventor 杨防祖杨家强金磊詹东平吴德印田中群
Owner XIAMEN UNIV