Novel cyanide-free silver plating electroplating liquid and electroplating technology

A cyanide-free silver-plating and electroplating technology, applied in the field of electrochemical silver-plating, can solve problems such as difficulty in treatment and maintenance of plating solution, increase in production cost, etc., and achieve the effects of good discoloration resistance, reduced waste water treatment cost, and reduced pollution

Inactive Publication Date: 2015-11-25
CHONGQING LIDAO SURFACE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Such as U.S. Patent USP4925491, due to the addition of various additives in the electroplating solution, the electroplating product that the coating is bright and delicate, and the coating performance meets the requirements for use, but there are too many types of additives in the plating solution, the follow-up treatment and maintenance of the plating solution is quite difficult, and the production cost is also high. increase accordingly

Method used

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  • Novel cyanide-free silver plating electroplating liquid and electroplating technology
  • Novel cyanide-free silver plating electroplating liquid and electroplating technology
  • Novel cyanide-free silver plating electroplating liquid and electroplating technology

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1), pretreatment→washing→activation→washing

[0025] First put the polished and water-washed plated substrate into a mixed aqueous solution containing 180g / L of concentrated sulfuric acid and 25g / L of OP emulsifier, soak for 3 minutes at 80°C, and then transfer to a solution containing 100g / L of concentrated hydrochloric acid and dodecane In the mixed aqueous solution of 10g / L sodium persulfate, immerse at room temperature for 2 minutes, take it out and rinse it with distilled water; Soak in the mixed aqueous solution at 80°C for 60 seconds, take it out and rinse it with distilled water for later use.

[0026] (2), pre-plated silver

[0027] The composition of the cyanide-free silver plating pre-plating solution is: silver nitrate 3g / L, methanesulfonic acid 50g / L, hydantoin 50g / L, potassium hydroxide 30g / L, potassium carbonate 30g / L, nicotinic acid 25g / L. Mix each component uniformly according to the raw material formula to prepare a cyanide-free silver plating pre-p...

Embodiment 2

[0043] Step (1) is the same as step (1) in embodiment 1

[0044] Step (2) is the same as step (2) in embodiment 1

[0045] (3), silver plating→recycling→washing

[0046] The cyanide-free silver plating solution consists of: silver nitrate 2.5g / L, potassium carbonate 50g / L, hydantoin 52g / L, potassium gluconate 0.1g / L, potassium malate 100g / L, citric acid 0.1g / L, Hydantoin 0.1g / L, butynediol 154g / L, alkylsulfonic acid surfactant 20g / L. Mix each component uniformly according to the raw material formula to prepare a cyanide-free silver plating solution, and adjust the pH value of the solution to 10.

[0047] Take the workpiece pre-plated in step (2) as the cathode, and the pure silver plate as the anode, immerse in the above electroplating solution, keep the solution temperature at 45°C, and the cathode current density 0.01A / dm 2 , DC plating time 120min, stirring speed (cathode movement) 4m / min, using continuous filter plating. After the electroplating is completed, immerse t...

Embodiment 3

[0058] Step (1) is the same as step (1) in embodiment 1

[0059] Step (2) is the same as step (2) in embodiment 1

[0060] (3), silver plating→recycling→washing

[0061] The composition of the cyanide-free silver plating solution is: silver nitrate 4g / L, potassium carbonate 2g / L, hydantoin 2g / L, potassium gluconate 100g / L, potassium malate 51g / L, citric acid 76g / L, hydantoin Urea 0.1g / L, butynediol 280g / L, alkylsulfonic acid surfactant 10.5g / L. Mix each component uniformly according to the raw material formula to prepare a cyanide-free silver plating solution, and adjust the pH value of the solution to 9.

[0062] Take the workpiece pre-plated in step (2) as the cathode, and the pure silver plate as the anode, immerse in the above electroplating solution, keep the solution temperature at 20°C, and the cathode current density 100A / dm 2 , DC plating time 1min, stirring speed (cathode movement) 1m / min, using continuous filter plating. After the electroplating is completed, im...

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Abstract

The invention provides novel cyanide-free silver plating electroplating liquid and an electroplating technology. The cyanide-free silver plating electroplating liquid comprises, by mass concentration, 1.5-4 g/L of silver nitrate, 2-50 g/L of potassium carbonate, 2-100 g/L of hydantoin, 0.1-100 g/L of potassium gluconate, 0.1-100 g/L of potassium malate, 0.1-150 g/L of citric acid, 0.1-280 g/L of hydantoin, 0.1-280 g/L of butynediol and 0.001-20 g/L of alkyl sulfonic acid surface active agent. The electroplating technology comprises the steps of pretreatment, washing, activating, washing, beforehand silver plating, silver plating, recycling, washing, adjusting treatment, washing, hot water washing (80 DEG C), washing and silver protective agent treatment. The novel silver plating technology has the main beneficial effects that firstly, the plating liquid is very stable and easy to control, the current efficiency of the plating liquid is high, and the dispersing capability and covering capability are good; secondly, a cyanide-free formula is adopted in the electroplating liquid, potential danger of cyanide is eliminated, and pollution to the environment is greatly reduced; and thirdly, the various properties of a plating layer are not lower than those of cyaniding silver plating, and a functional cyaniding silver plating technology can be thoroughly replaced.

Description

technical field [0001] The invention belongs to the technical field of electrochemical silver plating, in particular to a novel cyanide-free silver plating solution and an electroplating process. Background technique [0002] Silver is a silvery-white, malleable, malleable and reflective precious metal, which is used as a decorative coating on musical instruments, tableware, jewelry, medals, etc. The silver-plated layer has good conductivity and solderability, and is widely used in industries such as electrical appliances, electronics, communication equipment, and instrumentation manufacturing. [0003] Cyanide-free silver plating is one of the most difficult plating types in the cyanide-free electroplating process. As early as the climax of cyanide-free electroplating activities in the 1970s, many cyanide-free silver plating processes were developed in China, from thiosulfate silver plating to nicotinic acid silver plating, from NS silver plating to succinimide silver plat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/46C25D5/00
Inventor 胡国辉欧忠文马捷刘军肖春燕包海生
Owner CHONGQING LIDAO SURFACE TECH
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