Surface chromium electroplating technique of magnesium alloy die casting

A technology of electroplating chrome and die casting, which is applied in metal material coating process, liquid chemical plating, coating and other directions to achieve the effects of stable plating solution performance, uniform coating thickness and high corrosion resistance

Inactive Publication Date: 2014-07-02
无锡市锡山区鹅湖镇荡口青荡金属制品厂
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Magnesium alloy die castings have been widely used in the fields of automobiles, transportation, aerospace and other fields, and the application of some die castings requires electroplating on the surface. However, there are few reports on the electroplating technology of magnesium alloy die castings in the prior art

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A chrome-plating process on the surface of magnesium alloy die-casting parts, said process comprising the following steps: alkali cleaning → pickling → activation → zinc immersion → cyanide-free copper plating → electroless nickel plating → chromium electroplating, specifically:

[0021] Alkali washing: Alkali washing solution: NaOH18g / L, Na 2 CO 3 10H 2 O16g / L, sodium lauryl sulfate 0.6g / L, the balance is water; the process is: temperature: 65-75°C, time: 6min;

[0022] Pickling: pickling solution: phosphoric acid 25g / L, Na 3 PO 4 12H 2 O20g / L, ferric nitrate 15g / L, potassium permanganate 34g / L, zinc sulfate 5g / L, the balance is water; the process is: temperature: 25-35°C, time: 40s;

[0023] Activation: Activation solution: K 4 P 2 o 7 ·3H 2 O: 130g / L, Na 2 CO 3 : 30g / L, NH 2 HF: 10g / L, the balance is water; the process is: temperature: 60-65°C, time: 4min;

[0024] Zinc dipping: The composition of zinc dipping solution is: zinc sulfate 20g / L, zinc carbon...

Embodiment 2

[0029] A chrome-plating process on the surface of magnesium alloy die-casting parts, said process comprising the following steps: alkali cleaning → pickling → activation → zinc immersion → cyanide-free copper plating → electroless nickel plating → chromium electroplating, specifically:

[0030] Alkali washing: Alkali washing solution: NaOH20g / L, NaOH 2 CO 3 10H 2 O14g / L, sodium lauryl sulfate 0.8g / L, the balance is water; the process is: temperature: 65°C, time: 6-10min;

[0031] Pickling: pickling solution: phosphoric acid 27g / L, Na 3 PO 4 12H 2 O18g / L, ferric nitrate 25g / L, potassium permanganate 32g / L, zinc sulfate 7g / L, the balance is water; the process is: temperature: 25-35°C, time: 30s;

[0032] Activation: Activation solution: K 4 P 2 o 7 ·3H 2 O: 140g / L, Na 2 CO 3 : 20g / L, NH 2 HF: 12g / L, the balance is water; the process is: temperature: 60-65°C, time: 3min;

[0033] Zinc dipping: The composition of the zinc dipping solution is: zinc sulfate 24g / L, zinc ca...

Embodiment 3

[0038] A chrome-plating process on the surface of magnesium alloy die-casting parts, said process comprising the following steps: alkali cleaning → pickling → activation → zinc immersion → cyanide-free copper plating → electroless nickel plating → chromium electroplating, specifically:

[0039] Alkali washing: Alkali washing solution: NaOH19g / L, Na 2 CO 3 10H 2 O15g / L, sodium lauryl sulfate 0.7g / L, the balance is water; the process is: temperature: 65-75°C, time: 8min;

[0040] Pickling: pickling solution: phosphoric acid 26g / L, Na 3 PO 4 12H 2 O19g / L, ferric nitrate 20g / L, potassium permanganate 33g / L, zinc sulfate 6g / L, the balance is water; the process is: temperature: 25-35°C, time: 35s;

[0041] Activation: Activation solution: K 4 P 2 o 7 ·3H 2 O: 135g / L, Na 2 CO 3 : 25g / L, NH 2 HF: 11g / L, the balance is water; the process is: temperature: 60-65°C, time: 3.5min;

[0042] Zinc dipping: The composition of the zinc dipping solution is: zinc sulfate 22g / L, zinc ...

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PUM

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Abstract

The invention discloses a surface chromium electroplating technique of a magnesium alloy die casting, which comprises the following steps: alkali washing, acid washing, activating, zinc immersion and cyanideless chromium electroplating, chemical nickel plating and chromium electroplating. By selecting the plating solutions in various steps and regulating the content, the plating solution has stable performance, and favorable technical effects can be obtained for each treatment, thereby laying favorable base for subsequent techniques. The finally prepared chromium coating has high chromium coating; and the metallic coating has uniform coating thickness and high corrosion resistance. The whole plating process does not use any cyanide, and the fluoride consumption is lower than that in the prior art, so the plating technique is green and environment-friendly.

Description

technical field [0001] The invention relates to the technical field of electroplating, in particular to a chromium electroplating process on the surface of a magnesium alloy die casting. Background technique [0002] Magnesium alloy is known as the green metal structural material in the 21st century. It has low density, high specific strength and specific stiffness, and excellent damping, machinability, and casting performance. It has been increasingly widely used in the automotive industry, aerospace industry, and electronics industry. application. Magnesium is rich in raw materials and ranks eighth among natural resources, but as a structural material, its poor corrosion resistance restricts its wider use. [0003] The standard electrode potential of magnesium is -2.34V, which has high reactivity. In air or solution, magnesium alloy will quickly form a very thin passivation film, which will lead to the metal coating and magnesium substrate during electroplating or electro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/42C23G1/22C23G1/12C23C18/18C23C18/52C23C18/36C25D3/38C25D3/06
CPCC23C18/1653C23C18/34C23G1/12C25D3/06C25D3/38C25D5/42C25D7/00
Inventor 钱永清
Owner 无锡市锡山区鹅湖镇荡口青荡金属制品厂
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