Method for preparing Al-Al2O3 composite coating on surface of magnesium alloy

A composite coating and magnesium alloy technology, applied in the direction of surface reaction electrolytic coating, metal material coating process, coating, etc., can solve the problems of large porosity, substantive requirements, low coating efficiency, etc. It achieves the effect of favorable corrosion resistance, high energy utilization efficiency and high bonding strength

Inactive Publication Date: 2010-09-15
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, in order to eliminate the residual stress between the substrate and the ceramic coating, thermal spraying Al-Al has been developed. 2 o 3 /TiO 2 Gradient coating improves the thermal shock resistance of the coating, but the performance of the magnesium alloy substrate is inevitably not affected by the thermal effect of spraying
The WC-Co coating was prepared on the surface of magnesium alloy by high-velocity flame spraying (HVOF). Due to the "self-roughening" effect of the sprayed particles, the obtained coating has a high bonding strength (> 40MPa), but due to the coating's The cathode characteristics and large porosity lead to the deterioration of the corrosion performance of the matrix magnesium alloy; when an Al transition coating is added between the coating and the substrate, although the protective performance is improved, the bonding between the transition layer and the substrate is relative

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] 1. Material preparation: After AZ91D magnesium alloy is cut and polished, use ultrasonic cleaning in acetone solution to degrease.

[0024] 2. Sandblasting: Sandblasting the surface of the magnesium alloy with glass sand to remove surface oxide and increase roughness.

[0025] 3. Cold spraying aluminum: the powder particle size of spraying aluminum powder is 600 mesh, the temperature of spraying gas (helium, argon or nitrogen) is set at 150-220°C, the pressure is 1.8-2.1MPa, the spraying distance is 20-40mm, and the spraying time is In 20 minutes, the thickness of the aluminum coating is about 2mm.

[0026] 4. Grinding: Properly grind the surface of the sprayed aluminum sample to make it smooth and bright.

[0027] 5. Plasma oxidation: sodium hydroxide 2g / L, sodium silicate 10g / L, the rest is water, and the temperature is room temperature. Oxidation is carried out by pulse method, the pulse frequency is 1000Hz, and the current density is 2A / dm 2 , the oxidation time ...

Embodiment 2

[0030] 1. Material preparation: After AZ91D magnesium alloy is cut and polished, use ultrasonic cleaning in acetone solution to degrease.

[0031] 2. Sandblasting: Sandblasting the surface of the magnesium alloy with glass sand to remove surface oxide and increase roughness.

[0032] 3. Cold spraying aluminum: the powder particle size of spraying aluminum powder is 800 mesh, the temperature of spraying gas (helium, argon or nitrogen) is set at 150-220°C, the pressure is 1.8-2.1MPa, the spraying distance is 20-40mm, and the spraying time is In 20 minutes, the thickness of the aluminum coating is about 2mm.

[0033] 4. Grinding: Properly grind the surface of the sprayed aluminum sample to make it smooth and bright.

[0034] 5. Oxalic acid anodic oxidation: the concentration of oxalic acid is 60g / L, and the rest is water; the oxidation temperature is room temperature, and the anode current density is 1.5A / dm 2 , the oxidation time is 60 minutes, and the oxide film thickness is ...

Embodiment 3

[0037] 1. Material preparation: After AZ31B magnesium alloy is cut and polished, use ultrasonic cleaning in acetone solution to remove oil.

[0038] 2. Etching: Na 4 P 2 o 7 .10H 2 O 40g / L, Na 2 CO 3 3.7g / L, NaNO 3 5g / L, NaH 2 PO 4 .2H 2 0.5g / L, the rest is water, the temperature is 50-70°C, and it is treated for 0.5-5 minutes. After taking it out, wash it with tap water for 1-2 minutes, and then wash it with deionized water for 1-2 minutes.

[0039] 3. Activation: HF 30ml / L, ZnO 20g / L, the rest is water, temperature 10-35°C, treatment for 0.5-5 minutes, immediately wash with tap water for 1-2 minutes after taking it out, and then wash with deionized water for 1-2 minutes minute.

[0040] 4. Pre-galvanized: ZnSO 4 .7H 2 O 35.6g / L, Na 4 P 2 o 7 .10H 2 O 134g / L, C 6 h 5 Na 3 o 7 .2H 2O10g / L, KF.2H 2 O 10g / L, sodium lauryl sulfate 0.1g / L, the rest is water, PH=9.0~10.0, temperature 40~70℃, cathode current density 0.1~0.5A / dm 2 , the time is 5 to 60 minutes...

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Abstract

The invention relates to a method for preparing an Al-Al2O3 composite coating on the surface of magnesium alloy, belonging to the technical field of metal surface treatment. The Al/Al2O3 composite coating prepared on the surface of the magnesium alloy by a calorization-oxidation method has high corrosion resistance and rigidity. The method comprises the following main steps of: firstly, coating an aluminum coating to the magnesium alloy, and then electrochemically oxidizing the aluminum coating to form an aluminum oxide film layer having extremely high corrosion resistance and rigidity, wherein a cold spraying method or a molten-salt aluminum electroplating method is used in the preparation process of the aluminum coating of the magnesium alloy, and common anodic oxidization and plasma anodic oxidization are used for the oxidation of the aluminum coating. By coating the aluminum coating to the surface of the magnesium alloy to carry out calorization treatment and then carrying out electrochemical anodic oxidization, the invention enhances the comprehensive protective performance of the surface of the magnesium alloy, and the Al/Al2O3 composite coating prepared on the surface of the magnesium alloy has the advantages of large bonding strength, high rigidity, good corrosion resistance and the like, thereby being the ideal protective coating for the magnesium alloy.

Description

technical field [0001] The invention relates to the preparation of Al-Al on the surface of magnesium alloy 2 o 3 A composite coating method belongs to the technical field of metal surface treatment. Background technique [0002] Lightweight is the inevitable requirement and development trend of equipment technical performance optimization and mitigation of environmental (emission) impact. Due to its high specific strength, specific stiffness, and good damping properties, magnesium alloy is the most potential metal structural material to meet the development of lightweight and environmental protection. Compared with aluminum alloys, magnesium alloys can increase the weight reduction potential by 20-25%. However, the wear resistance and thermodynamic stability of magnesium alloy are poor, and because the oxide (film) is loose (PBR<1), it cannot form a self-passivating dense oxide film in the environment like aluminum alloy. At the same time, magnesium alloys have high r...

Claims

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Application Information

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IPC IPC(8): C23C28/02C25D11/04C25D11/10C25D3/66C25D5/30C23C24/00
Inventor 严川伟张吉阜王福会
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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