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High-performance cyanide-free silver pre-plating liquid

A technology of cyanide-free silver plating and pre-plating solution, which is applied in the field of electrochemical silver plating, can solve the problem of "weak bonding force between the substrate and the coating, etc., and achieve strong process operability, good bonding force, dispersion ability and covering ability Good results

Inactive Publication Date: 2014-11-19
CHONGQING LIDAO SURFACE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a high-performance cyanide-free silver plating pre-plating solution for the problem of "weak bonding between the substrate and the coating" existing in the existing cyanide-free silver plating technology

Method used

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  • High-performance cyanide-free silver pre-plating liquid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] (1), substrate activation treatment

[0035] 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.

[0036] (2), composition and preparation process of cyanide-free silver plating pre-plating solution

[0037] The composition of the cyanide-free silver plating pre-plating solution is: silver nitrate 1g / L, methanesulfonic acid 20g / L, hydantoin 20g / L, potassium hydroxide 50g / L, potassium carbonate 50g / L; The preparation process of the solution is as follows: first add pure wate...

Embodiment 2

[0049] Step (1) is the same as step (1) in Example 1.

[0050] (2), composition and preparation process of cyanide-free silver plating pre-plating solution

[0051] 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; The preparation process of the cyanide-free silver plating pre-plating solution is as follows: first add pure water with a total volume of 25% to the plating tank; then add the pre-weighed nicotinic acid, potassium carbonate and potassium hydroxide in sequence, stir and heat up to 27°C ; Dissolve silver nitrate with a small amount of pure water, slowly add it to the above solution under stirring, and adjust the pH value to 10; finally add methanesulfonic acid and hydantoin, and replenish pure water to the required volume.

[0052] (3), pre-plated silver

[0053] With step (1) activated plated base s...

Embodiment 3

[0062] Step (1) is the same as step (1) in Example 1.

[0063] (2), composition and preparation process of cyanide-free silver plating pre-plating solution

[0064] The composition of the cyanide-free silver plating pre-plating solution is: silver nitrate 5g / L, methanesulfonic acid 5g / L, hydantoin 100g / L, potassium hydroxide 10g / L, potassium carbonate 10g / L, nicotinic acid 10g / L. The preparation process of the cyanide-free silver-plating pre-plating solution is as follows: first add 25% pure water to the cleaned plating tank; then add the pre-weighed nicotinic acid, potassium carbonate and potassium hydroxide successively, stir and Raise the temperature to 35°C; then dissolve silver nitrate with a small amount of pure water, slowly add it to the above solution under stirring, and adjust the pH value to 9; finally add methanesulfonic acid and hydantoin, and replenish pure water to the required volume.

[0065] (3), pre-plated silver

[0066] With the plated part substrate aft...

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Abstract

The invention provides high-performance cyanide-free silver pre-plating liquid aiming at the problem of poor adhesion between a substrate and a plating layer in an existing cyanide-free silver plating technology. The pre-plating liquid mainly comprises silver nitrate, methylsulphonic acid, hydantoin, potassium hydroxide, potassium carbonate and nicotinic acid. A high-performance cyanide-free silver pre-plating process has the main advantages that the process is strong in operability and easy to control, the current density is 0.2-0.5 A / dm<2>, the dispersing and covering capabilities are good, and the process adapts to the pre-electroplating of complicated parts; the adhesion between the substrate and the plating layer obtained by silver pre-plating and silver plating is good, the color change resistance is good, and the conductivity and weldability are excellent; by a high-concentration complexing agent and a stabilizer, the pre-plating liquid can be stored for a long term without hydrolysis and is hardly decomposed under the electroplating process conditions. The cyanide-free silver pre-plating liquid provided by the invention can be used for copper, iron and alloy castings, also can be used for silver plating of plastic surfaces, and is widely applied to product surface finishing and the like in the fields of aviation and electronic industries.

Description

technical field [0001] The invention belongs to the technical field of electrochemical silver plating, in particular to a high-performance cyanide-free silver plating pre-plating solution. Background technique [0002] The silver-plated layer has good electrical conductivity and light reflection ability, high chemical stability, and has been widely used in decorations, tableware, electronic products, etc. Cyanide silver plating has been around for more than 100 years, and it is still widely used. The main reason is that silver ions form a very stable complex Ag(CN) with cyanide in solution. 2- , the crystallization of the coating is fine, which can meet the needs of different silver plating products. However, the cyanide silver plating bath contains highly toxic substance cyanide, which is extremely harmful to the human body and the environment, requires high production conditions, and the bath wastewater treatment process is complicated and expensive. With the enhancement...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/46C25D5/00
Inventor 胡国辉刘军包海生肖春燕王东风陶熊新罗虹
Owner CHONGQING LIDAO SURFACE TECH
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