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Method for removing excessive citrate contained in gold-plating solution

A technology of citrate and electroplating gold, which is applied in the direction of electrolysis process, electrolysis components, cells, etc. It can solve the problems of dark coating, difference in thickness, and lower upper limit of current density, etc., and achieve the effect of low cost and simple operation

Inactive Publication Date: 2010-06-16
QINGDAO UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Second, the upper limit of the current density is reduced, and the high current density area is prone to "burning" phenomenon
[0005] Third, the dispersion ability of the coating is reduced, and the coating in the low current density area is dark, and the thickness of the coating is significantly different from other parts

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0037] The formulation of the plating solution adopts commercially available potassium gold citrate products without inorganic free cyanide and Technic electroplating thick gold additives. The process formula is as follows:

[0038] Potassium gold citrate 22g / L; conductive salt 90g / L; auxiliary salt 45g / L; adjusting salt 30g / L; brightener A: 2ml / L; B: 10ml / L pH=4.5; temperature 50°C; D K 15A / dm 2 .

[0039] According to the above process conditions, the coating is yellow and bright. Add potassium citrate 100g / L, the high current density area of ​​the coating will be severely burnt, and the coating will be dark in the low current density area. Adding brightener has no effect. According to the treatment method in the present invention, the pH value is adjusted with hydrochloric acid; 8g / L of hexamethylenetetramine and 54g / L of calcium chloride are added at one time, and an appropriate amount of brightener is added to the regenerated gold plating solution after filtration, an...

example 2

[0041] The process formula is as follows:

[0042] Gold Potassium Citrate 20g / L; Potassium Citrate 150g / L; Potassium Dihydrogen Phosphate 25g / L; Citric Acid 40g / L; Brightener 10ml / L; pH=4.5; K 15A / dm 2 .

[0043] According to the above process conditions, the coating is yellow and bright. Add potassium citrate 100g / L, the high current density area of ​​the coating will burn severely, and the coating will become dark in the low current density area. Adding brightener has no effect. According to the treatment method in the present invention, adjust the pH value with hydrochloric acid; add hexamethylenetetramine 6g / L, calcium carbonate consumption 50g / L at one time, add brightener to the regenerated gold plating solution after filtration, and the coating quality returns to normal.

[0044] The above-mentioned aqueous solution of calcium-containing substances mainly refers to an aqueous solution of calcium salt.

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PUM

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Abstract

The invention discloses a method for removing excessive citrate contained in a gold-plating solution, which uses a solid matter or a water solution, containing calcic materials, as a regeneration treating agent and comprises the following steps of: adding the solid matter or the water solution, containing the calcic materials, into a solution to be treated so as to generate calcium citrate sediments; and filtering to obtain a regenerated citrate gold-plating solution, wherein the regenerated citrate gold-plating solution can be put into normal production for use after being regulated in pH value and replenished with an additive. The invention can effectively remove the excessive citrates generated by continuously adding potassium citrate in the citrate gold-plating production process and enable the citrate gold-plating solution to be used for a long time by keeping a good state all the time; and besides, the invention has low cost, easy operation, and the like in treating the citrate gold-plating solution.

Description

technical field [0001] The invention relates to a method for removing excess citrate in an electroplating gold solution, in particular to a method for removing excess potassium citrate in a citrate electroplating gold solution. Background technique [0002] Gold has good electrical conductivity and stability, and is widely used in integrated circuit pins, circuit board plating and jewelry decorative plating. In the current gold plating process widely used at home and abroad, the source of gold ions in the plating solution does not use gold anodes, but adds soluble gold salts. According to the difference of gold ion supplementary salt, the gold plating process is divided into two types: cyanide gold plating and citric acid gold plating. The former plating solution contains highly toxic inorganic cyanide, which belongs to the eliminated process in the national technology-oriented catalog; the latter replaces potassium aurous cyanide with gold potassium citrate without cyanide...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D21/18C25D3/48
Inventor 张来祥谢洪波韩云海马学奎
Owner QINGDAO UNIV
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