Anode stripping solution for magnesium and magnesium alloy nickel-plating layer and method for stripping coating

A technology of anode stripping and magnesium alloy, which is applied in the field of metal material surface treatment, can solve the problems of aggravating stripping solution volatilization, magnesium alloy substrate corrosion, and surrounding environmental pollution.

Inactive Publication Date: 2011-01-05
UNIV OF SHANGHAI FOR SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this formula uses high-concentration HF acid, and HF acid is a highly volatile and highly corrosive toxic medium. In addition, a large amount of gas is emitted from the cathode during stripping, which aggravates the volatilization of the stripping solution. The surrounding environment causes pollution, severely corrodes the production equipment, and the solution contains NaNO 3 , will cause corrosion to the magnesium alloy substrate, so it is necessary to find a safer and more effective stripping process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] First prepare the eliminator according to the following volume percentage ratio:

[0025] HF 5%

[0026] ammonium fluoride 10%

[0027] Citric acid 5%

[0028] Sodium dodecyl sulfonate 0.1%

[0029] The balance is water

[0030] Then degrease the magnesium alloy workpiece with unqualified coating, rinse it with clean water, install it on the hanger, and put it into the above stripping solution. The workpiece is used as the anode, and the cathode is nickel-plated stainless steel sheet, and the current density for stripping is 34A. / dm 2 , The voltage is 4~6V. During the removal process, stop the removal when the current gradually drops to zero, take out the workpiece, rinse it with clean water, and then re-plating or electroless plating.

Embodiment 2

[0032] First prepare the eliminator according to the following volume percentage ratio:

[0033] HF 10%

[0034] ammonium fluoride 2 %

[0035] Citric acid 15%

[0036] Sodium dodecyl sulfonate 0.5%

[0037] The balance is water

[0038] Then degrease the magnesium alloy workpiece with unqualified coating, rinse it with clean water, install it on the hanger, and put it into the above stripping solution. The workpiece is used as the anode, and the cathode is a nickel-plated stainless steel sheet. The current density for stripping is 4.3. A / dm 2 , voltage 4 ~ 6V. During the stripping process, stop stripping when the current drops to zero, take out the workpiece, rinse it with clean water, and then re-plating or electroless plating.

Embodiment 3

[0040] First prepare the eliminator according to the following volume percentage ratio:

[0041] HF 7 %

[0042] ammonium fluoride 6%

[0043] Citric acid 8%

[0044] Sodium dodecyl sulfonate 0.3%

[0045] The balance is water

[0046] Then degrease the magnesium alloy workpiece with unqualified coating, rinse it with clean water, install it on the hanger, and put it into the above stripping solution. The workpiece is used as the anode, and the cathode is nickel-plated stainless steel sheet, and the current density for stripping is 10A. / dm 2 , voltage 4 ~ 6V. During the stripping process, stop stripping when the current drops to zero, take out the workpiece, rinse it with clean water, and then re-plating or electroless plating.

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PUM

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Abstract

The invention discloses an anode stripping solution for a magnesium and magnesium alloy nickel-plating layer and a method for stripping a coating. The stripping solution consists of the following components in percentage by volume: 5 to 10 percent of HF, 2 to 10 percent of fluoride, 5 to 15 percent of complexing agent, 0.1 to 0.5 percent of sodium dodecyl sulfate, and the balance of water. The method comprises the following steps of: preparing the stripping solution for the magnesium and magnesium alloy nickel-plating layer; and stripping the magnesium and magnesium alloy nickel-plating layer. During stripping, a magnesium alloy workpiece with an unqualified coating is used as an anode, and a cathode is a nickel-plating stainless steel plate. The method for stripping the magnesium and magnesium alloy nickel-plating layer by using the anode stripping solution for the magnesium and magnesium alloy nickel-plating layer can trip off the nickel-plating layer by one step at high speed without corrosion on the surface of a matrix; and after stripping, the matrix can be directly subject to electroplating or chemical plating once again. The hydrofluoric acid used in the stripping solution has low concentration, so the pollution to the environment and harm to bodies of operators are reduced.

Description

technical field [0001] The invention relates to an anode stripping solution for magnesium and magnesium alloy nickel coatings and a stripping method for the coatings, belonging to the field of surface treatment of metal materials. Background technique [0002] Although the most advanced plating technology is used, some defective parts will always be inspected after plating. If the defective parts have a large enough economic value, economically, it is always desirable to remove the parts on the parts. Fully or partially plated and re-plated. There are many studies on metal coatings, but the research on metal coating stripping is often neglected, and few studies are carried out. [0003] The anode stripping method is a commonly used coating stripping method, which can provide a suitable and stable stripping speed, the accumulation of reaction products is slow, and the chemical raw materials are usually cheap. The anodic stripping of magnesium and magnesium alloy nickel coat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25F5/00
Inventor 刘新宽刘平马凤仓李伟陈小红何代华
Owner UNIV OF SHANGHAI FOR SCI & TECH
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