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Method for preparing magnesium alloy composite coating with self-repair function

A composite coating and magnesium alloy technology, which is applied in the direction of metal material coating technology, coating, surface reaction electrolytic coating, etc., can solve the problems of failure to prepare magnesium alloy protective coating, thin vapor deposition film, and corrosion resistance. Poor and other problems, to achieve good self-healing performance, fast coating speed, good bonding effect

Active Publication Date: 2016-08-24
GUANGDONG INST OF NEW MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, hexavalent chromium is toxic and has been banned by the European Union, etc.
However, the existing metal coating preparation technologies such as thermal spraying, electroplating, and chemical plating have problems such as poor bonding force, poor corrosion resistance, thin vapor deposition film, poor corrosion resistance, and low deposition efficiency.
Therefore, it has not been possible to prepare protective coatings for magnesium alloys with both corrosion resistance and self-healing properties.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 1. Pretreatment: Use 400~1000# sandpaper or grinder to polish the surface of the magnesium alloy, remove oil and degrease;

[0019] 2. Micro-arc oxidation: use micro-arc oxidation electrolyte, the composition of electrolyte is: sodium silicate 20g / L, sodium hydroxide 2g / L, sodium metaaluminate 5g / L, glycerol 2ml / L, the rest is Deionized water; when the pulse power frequency is 500Hz, the control current density is 2.5A / dm 2 , the duty cycle is 8%, the micro-arc oxidation time is 25min, and the oxide film thickness is 20μm;

[0020] 3. Ion cleaning: clean and dry the magnesium alloy after micro-arc oxidation, and put it under a pressure of 7×10 -3 In the vacuum coating chamber at Pa and 100°C, adjust the argon pressure to 2.0Pa, pulse bias duty cycle to 20%, bias voltage to 1000V, and discharge cleaning for 5 minutes;

[0021] 4. Arc ion coating: use pure aluminum target material, after the argon ion bombardment, the gas in the coating chamber reaches a pressure of 3×1...

Embodiment 2

[0024] 1. Pretreatment: Use 400~1000# sandpaper or grinder to polish the surface of the magnesium alloy, remove oil and degrease;

[0025] 2. Micro-arc oxidation: use micro-arc oxidation electrolyte, the composition of electrolyte is: sodium silicate 5g / L, sodium hydroxide 5g / L, sodium metaaluminate 1g / L, glycerol 8ml / L, the rest is Deionized water; when the pulse power frequency is 800Hz, rise to 250V within 5min, rise to 450V within 10min, keep the voltage at 450V, the duty cycle is 20%, the micro-arc oxidation time is 60min, and the oxide film thickness is 45μm;

[0026] 3. Ion cleaning: clean and dry the magnesium alloy after micro-arc oxidation, and place it under a pressure of 8×10 -3 In the vacuum coating chamber at Pa and 200°C, adjust the argon pressure to 3.0Pa, pulse bias duty cycle to 25%, bias voltage to 1000V, and discharge cleaning for 2 minutes;

[0027] 4. Arc ion coating: use pure titanium target material, after the argon ion bombardment, the gas in the coat...

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Abstract

A method for preparing a magnesium alloy composite coating with a self-repair function comprises the following steps that the surface of a magnesium alloy is polished, and oil removal and degreasing are carried out; an electrolyte is subjected to micro-arc oxidation, a current or voltage control method is adopted, the pulse power frequency and the duty ratio are adjusted, and the micro-arc oxidation time ranges from 15 min to 60 min; the magnesium alloy obtained after micro-arc oxidation is cleaned and dried and is put in a vacuum coating chamber with the pressure being (7-8)*10<-3> Pa and the temperature ranging from 100 DEG C to 200 DEG C, the pressure of argon is adjusted to range from 2 Pa to 3 Pa, the pulsed bias duty ratio ranges from 20% to 30%, the bias voltage ranges from 800 V to 1,000 V, and discharge cleaning is carried out for 2 min to 5 min; a pure aluminum or pure titanium target is adopted, and argon ion bombardment is finished till the pressure ranges from (3-5)*10<-1> Pa, the bias duty ratio ranges from 40% to 50%, and the bias voltage ranges from 500 V to 1,000 V; and the arc current ranges from 60 A to 120 A, and the coating time ranges from 10 min to 60 min. In the method, chromium, fluoride, phosphorus, heavy metal ions and other harmful substances are avoided, and the prepared magnesium alloy coating has corrosion resistance, good heat conductivity and self-repair performance.

Description

technical field [0001] The invention relates to a preparation method of a magnesium alloy composite coating, in particular to micro-arc oxidation technology and arc ion coating technology. Background technique [0002] Magnesium alloy has the characteristics of high specific strength and specific stiffness, good casting performance, excellent electrical shielding and damping performance, and recyclability. It is widely used in aerospace, automobile and motorcycle, tools, electronic communications, optical instruments, computer manufacturing and other fields. . However, the electrode potential of magnesium alloy is extremely negative (-2.36V), and the volume ratio of natural oxide film to metal is 0.79. The natural oxide film cannot completely cover the substrate, and is loose and porous, which cannot protect the magnesium alloy substrate and has poor corrosion resistance. In order to improve the corrosion resistance of the magnesium alloy surface, many surface treatment tec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C28/00C25D11/30C23C14/32C23C14/18
CPCC23C14/18C23C14/325C23C28/322C23C28/345C25D11/024C25D11/30
Inventor 宋东福徐静农登郑开宏王顺成甘春雷
Owner GUANGDONG INST OF NEW MATERIALS
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