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Anti-nitridation process for copper-tin composite plating

A nitriding and copper-tin technology, which is applied in the field of metal surface treatment to prevent nitriding, carbon, and cyanide, can solve the problems of copper consumption and copper removal, long time consumption of copper removal, high cost of sewage treatment, etc., and achieve energy saving The effect of increasing the amount of copper, improving the plating efficiency, and reducing the plating time

Active Publication Date: 2015-04-22
GUIZHOU HONGLIN MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to solve the lack of pores in the coating, the thickness of the coating is often increased. The currently used process requires the thickness of the copper coating to be greater than 50um to meet the anti-seepage requirements. However, too thick a coating leads to a long time for electroplating and copper removal (both require more than 4 hours). Consumes a lot of copper and copper removal chemicals, especially chromic anhydride (hexavalent chromium) for copper removal, which leads to increased electroplating costs, high sewage treatment costs, and potential environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] In order to make the workpiece achieve the purpose of anti-nitriding, the following steps can be used when electroplating copper to the workpiece:

[0019] 1. Hanging

[0020] 2. Degreasing

[0021] 3. Wash with hot water

[0022] 4. Rinse with cold water

[0023] 5. Weak corrosion

[0024] Sulfuric acid (H 2 SO 4 Density 1.84) Industrial grade 150-200g / L

[0025] temperature room temperature

[0026] Time 0.1-2min

[0027] 6. Rinse with cold water

[0028] 7. Anode cleaning

[0029] Sulfuric acid (H 2 SO 4 Density 1.84) Industrial grade 500-600g / L

[0030] temperature room temperature

[0031] Time 30-60S

[0032] Current density 50-10 A / dm 2

[0033] Note: (1) Stainless steel, high-strength steel, heat-resistant steel, and high-temperature alloy steel need to carry out this process to improve the bonding force of the coating.

[0034] ⑵ After anode cleaning, the workpiece needs to be charged out of the tank.

[0035] 8. Rinse with cold wat...

example 1

[0062] Insoluble anode 304 or 314 stainless steel (cathode to anode ratio 1:1.5)

[0063] Note: ⑴ The bath is stirred with clean compressed air. During copper plating, the bath solution is continuously circulated and filtered.

[0064] (2) When copper-plating nitriding parts, the position of the workpiece should be changed 3 times by 90°. To ensure the uniformity of the coating.

[0065] 14. Flowing cold water wash

[0066] This process needs to be carefully cleaned with grade 2 deionized water and then transferred to the tin plating tank.

[0067] 15. Dark tin plating 5~8um

[0068] Stannous sulfate (SnSO4) chemically pure 15~25g / L

[0069] Sulfuric acid industrial grade 8~12%

[0070] Additive (LD-7720) Industrial grade 10~20ml / L

[0071] Temperature 15~25℃

[0072] Cathode current density 1~4A / dm 2

[0073] time 6 minutes

[0074] 16. Flowing cold water wash

[0075] 17. Stabilization treatment

[0076] Put the copper-tin-plated workpiece into a closed heat pre...

Embodiment 2

[0078] In order to make the workpiece achieve the purpose of anti-nitriding, the following steps can be used when electroplating copper to the workpiece:

[0079] 1. Hanging

[0080] 2. Degreasing

[0081] 3. Wash with hot water

[0082] 4. Rinse with cold water

[0083] 5. Weak corrosion

[0084] Sulfuric acid (H 2 SO 4 Density 1.84) Industrial grade 150-200g / L

[0085] temperature room temperature

[0086] Time 0.1-2min

[0087] 6. Rinse with cold water

[0088] 7. Anode cleaning

[0089] Sulfuric acid (H 2 SO 4 Density 1.84) Industrial grade 500-600g / L

[0090] temperature room temperature

[0091] Time 30-60S

[0092] Current density 50-10 A / dm 2

[0093] Note: (1) Stainless steel, high-strength steel, heat-resistant steel, and high-temperature alloy steel need to carry out this process to improve the bonding force of the coating.

[0094] ⑵ After anode cleaning, the workpiece needs to be charged out of the tank.

[0095] 8. Rinse with cold wat...

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Abstract

The invention discloses an anti-nitridation process for copper-tin composite plating, which comprises the following steps: deoiling and cleaning a workpiece, and then performing weak corrosion treatment on the workpiece with sulfuric acid; performing anodic cleaning on the workpiece, wherein the workpiece subjected to anodic cleaning needs to be taken out of the tank while electrified; performing nickel preplating: keeping the workpiece non-electrified and placing the workpiece in an electroplating solution for 2-4 minutes before nickel preplating, then preplating nickel for 1 mu m, and plating dark nickel for 1-2 mu m; performing activating treatment on the workpiece with sulfuric acid; and performing copper cyanideless electroplating, plating dark tin on the surface of the copper-electroplated layer of the workpiece, and finally performing stabilizing treatment. According to the electroplating process disclosed by the invention, the workpiece can similarly achieve the purpose of preventing nitridation, carburization and cyanogen infiltration in case of a thinner copper-plated layer, thus reducing the thickness of the copper-plated layer, reducing the copper consumption, shortening the electroplating time and improving the electroplating efficiency.

Description

technical field [0001] The invention relates to a process for preventing nitriding by copper-tin composite plating, which belongs to the technical field of metal surface treatment for preventing nitriding, carbon and cyanidation. Background technique [0002] Copper is a red ductile metal with a relative atomic mass of 63.5 and a density of 8.93g / cm3. The electrochemical equivalent Cu+ of copper is 2.372g / (A.h), and Cu2+ is 1.186g / (A.h). h), copper has poor chemical stability and is soluble in nitric acid, chromic acid and cyanide solutions. Copper is easily corroded by organic acids, and is also easily soluble in hot sulfuric acid. It reacts slowly in hydrochloric acid and dilute sulfuric acid solutions, and is not easy to react with alkali except ammonia water. Tin is a softer and more malleable metal with a relative atomic mass of 118.7 and a density of 7.3g / cm3. The electrochemical equivalent of tin Sn2+ is 2.214 / (A.h), and Sn4+ is 1.107g / (A.h). The chemical stability ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/10C25D5/48
CPCC25D5/10C25D5/505
Inventor 林兰贾亚洲刘鑫春
Owner GUIZHOU HONGLIN MACHINERY
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