Method for improving binding force of magnesium alloy surface galvanized coating by improving acid activation process

A pickling activation and magnesium alloy technology, which is applied in coatings, electrolytic coatings, etc., can solve the problem of pickling activation on the surface of magnesium alloys, affecting the bonding force between phosphate/metal composite films and magnesium alloys, and the quality of phosphate/metal composite films. problems, to achieve the effect of avoiding concentrated hydrogen evolution holes, prolonging the life of the solution, and reducing the concentration of free acid

Inactive Publication Date: 2014-05-21
WUXI SANZHOU COLD ROLLED SILICON STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the 11% hydrofluoric acid leaching of the conventional pickling activation process adopted in the above method cannot effectively pickle and activate the surface of the magnesium alloy, thereby affecting the relationship between the electrodeposited phosphate / metal composite film and the magnesium alloy. The binding force and quality of phosphate / metal composite films

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The required treatment solution of the present invention is prepared as follows:

[0029] Take 1.5g of zinc oxide and make a paste with water, dissolve it completely with 4ml of phosphoric acid, and then add the following reagents successively: 0.3g of sodium fluoride, 0.5g of molybdate, 0.1g of sodium dodecylsulfonate, 0.3g of tartaric acid , dilute to 1 liter with water.

[0030] The grade is AZ31 extruded magnesium alloy, and the surface treatment of the magnesium alloy product is carried out according to the following steps:

[0031] 1. Conventional mechanical decontamination: use sandblasting or sandpaper to polish, remove burrs, oxides, extrusion additives, processing oil and other foreign matter, and wash with water;

[0032] 2. Conventional alkali washing and degreasing: wash with 5g / l sodium hydroxide, 10g / l sodium phosphate, 10g / l sodium carbonate, 2g / l surfactant mixed solution, stir at room temperature for 1min; wash with water;

[0033] 3. Pickling activa...

Embodiment 2

[0037] The required treatment solution of the present invention is prepared as follows:

[0038] Phosphoric acid 2.5 ml / L, zinc dihydrogen phosphate 2 g / L, manganese carbonate 3 g / L, sodium fluoride 0.2 g / L, sodium dodecylsulfonate 0.05 g / L, sodium nitrate 0.1 g / L, sub Sodium nitrate 0.4 g / L, citric acid 0.1 g / L. Dissolve the reagents directly in water according to the above sequence to form the desired solution.

[0039] The grade is AZ31 extruded magnesium alloy, and the surface treatment of the magnesium alloy product is carried out according to the following steps:

[0040] 1. Conventional mechanical decontamination: use sandblasting or sandpaper to polish, remove burrs, oxides, extrusion additives, processing oil and other foreign matter, and wash with water;

[0041] 2. Conventional alkali washing and degreasing: wash with 5g / L sodium hydroxide, 10g / L sodium phosphate, 10g / L sodium carbonate, 2g / L surfactant mixed solution, stir at room temperature for 1min; wash with ...

Embodiment 3

[0046] The required treatment solution of the present invention is prepared as follows:

[0047] 2 grams of zinc dihydrogen phosphate, 0.3 grams of nickel nitrate, 0.3 grams of sodium fluoride, 0.2 grams of manganese dihydrogen phosphate, 0.1 grams of sodium dodecylsulfonate, 0.2 grams of sodium nitrate, 0.3 grams of sodium nitrite, 0.1 grams of citric acid , dissolved in 1 liter of water.

[0048] Take the grade as AZ31 extruded magnesium alloy, and follow the steps below to carry out surface treatment on the magnesium alloy product:

[0049] 1. Conventional mechanical decontamination: use sandblasting or sandpaper to polish, remove burrs, oxides, extrusion additives, processing oil and other foreign matter, and wash with water;

[0050] 2. Conventional alkali washing and degreasing: wash with 5g / L sodium hydroxide, 10g / L sodium phosphate, 10g / L sodium carbonate, 2g / L surfactant mixed solution, stir at room temperature for 1min; wash with water;

[0051] 3. Pickling activat...

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PUM

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Abstract

The invention relates to a method for improving binding force of a magnesium alloy surface galvanized coating by improving an acid activation process. The acid activation method is characterized by comprising the following steps: adjusting pH value to 1-5 by using ammonium water in 0.5g / L of thiourea, 10-40mL / L hydrogen nitrate (65%) and 0.5-1.5g / L oxalic acid, and soaking by an acid at room temperature for 10-50 seconds. By adopting the acid activation method, residual oxide skin and dirt can be effectively removed, and the surface is cleaner, has activity, and is good in binding force of coating and magnesium alloy, stronger in protective capability, and less in matrix loss in the treatment process.

Description

technical field [0001] The invention relates to a method for surface treatment of metal materials, in particular to a method for improving the binding force of electroplating layers on the surface of magnesium alloys by improving the pickling activation process. Background technique [0002] Magnesium alloys have high specific strength, specific stiffness and good casting, shock absorption, cutting, dimensional stability and excellent electromagnetic shielding properties. However, the surface structure of magnesium alloys is prone to corrosion, and the surface often needs to be treated to increase the protective performance of the magnesium alloy surface. Since the electrochemical potential of magnesium metal is about -2.37v, it is very easy to oxidize in the ordinary atmospheric environment. This layer of oxide film is loose and not firm, which cannot protect the substrate, and hinders the surface treatment of magnesium alloys, hinders Promotion and application of magnesiu...

Claims

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Application Information

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IPC IPC(8): C25D9/12C25D5/42C25D3/22C23G1/12
Inventor 刘茂见
Owner WUXI SANZHOU COLD ROLLED SILICON STEEL
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