Preparation method of micro-arc oxidation-composite chemical nickel plating coating layer on surface of magnesium alloy

A composite chemical plating and micro-arc oxidation technology is applied in the field of metal surface treatment to achieve the effects of simple and efficient preparation process, improving overall protection performance and bonding performance, and inhibiting polymerization reaction

Inactive Publication Date: 2014-11-12
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

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a method for sealing holes on the surface of the magnesium alloy micro-arc oxidation ceramic coating and preparing a composite electroless nickel coating, which is used to improve the corrosion resistance and corrosion resistance of the magnesium alloy substrate. The comprehensive performance of grinding, and improve the conductivity of the composite coating, to solve the protective requirements of magnesium alloy scratch resistance and corrosion resistance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1. Material preparation: After AZ91D magnesium alloy is cut, polished and polished, use ultrasonic cleaning in acetone solution to remove oil, and then ultrasonic cleaning in deionized water to remove organic matter and impurities.

[0031] 2. Micro-arc oxidation: In the electrolyte, sodium silicate is 15g / L, sodium hydroxide is 2g / L, sodium carbonate is 5g / L, the rest is water, and the temperature is 50°C; high-voltage pulse method is used for micro-arc oxidation, pulse Frequency is 500Hz, current density is 2A / dm 2 , the oxidation time is 40 minutes, and the thickness of the oxide film is 25 μm. The oxide film is a porous ceramic membrane with a porosity of 40% and a pore diameter of 2 to 5 μm.

[0032] 3. Hole sealing and pre-nickel plating

[0033] 1) Configuration of silane mixture. Mix and stir silane KH-560 and TEOS at a molar ratio of n(KH560):n(TEOS)=3:1 to obtain a silane mixture.

[0034] 2) The configuration of the hydrolysis catalyst. Acetic acid and ph...

Embodiment 2

[0050] The difference from Example 1 is:

[0051] 1. Material preparation: After the AZ31B magnesium alloy is cut, polished and polished, it is cleaned and degreased by ultrasonic cleaning in absolute ethanol solution, and then organic matter and impurities are removed by ultrasonic cleaning in deionized water.

[0052] 2. Micro-arc oxidation: In the electrolyte, sodium silicate is 10g / L, sodium hydroxide is 10g / L, sodium carbonate is 8g / L, the rest is water, and the temperature is 35°C. Micro-arc oxidation is carried out by high-voltage pulse method, the pulse frequency is 800Hz, and the current density is 2A / dm 2 , the oxidation time is 60min, and the thickness of the oxide film is 15μm. The oxide film is a porous ceramic membrane with a porosity of 35% and a pore size of 3-5μm.

[0053] 3. Hole sealing and pre-nickel plating

[0054] 1) Configuration of silane mixture. Mix and stir silane KH-560 and TEOS at a molar ratio of n(KH560):n(TEOS)=3:2 to obtain a silane mixture...

Embodiment 3

[0071] The difference from Example 1 is:

[0072] 1. Material preparation: After cutting, grinding and polishing the ZM5 magnesium alloy, use ultrasonic cleaning in organic solvent to remove oil, and then ultrasonic cleaning in deionized water to remove organic matter and impurities.

[0073] 2. Micro-arc oxidation: In the electrolyte, sodium silicate is 20g / L, sodium hydroxide is 6g / L, sodium carbonate is 8g / L, and the rest is water. 1000Hz, current density 3A / dm 2 , the oxidation time is 50 minutes, and the thickness of the oxide film is 20 μm. The oxide film is a porous ceramic film with a porosity of 50% and a pore diameter of 6-10 μm.

[0074] 3. Hole sealing and pre-nickel plating

[0075] 1) Configuration of silane mixture. Mix and stir silane KH-560 and TEOS at a molar ratio of n(KH560):n(TEOS)=5:2 to obtain a silane mixture.

[0076] 2) The configuration of the hydrolysis catalyst. Acetic acid and phytic acid are uniformly mixed in a molar ratio of n(acetic acid)...

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Abstract

The invention discloses a preparation method of a micro-arc oxidation-composite chemical nickel plating coating layer on the surface of a magnesium alloy, and belongs to the technical field of metal surface treatment. The preparation method comprises the following steps: firstly, the micro-arc oxidation is performed for the surface of a magnesium alloy matrix to form a porous ceramic coating layer on the surface; then, the hole sealing treatment is performed for the matrix with the porous ceramic coating layer by adopting nanometer self-assembly penetrant containing nickel salt; the nickel preplating treatment is performed for the matrix, after the hole sealing treatment, by adopting alcohol solution of sodium borohydride; and finally, the composite chemical nickel plating treatment is performed for the matrix, after the nickel preplating treatment, to form the micro-arc oxidation-composite chemical nickel plating coating layer on the surface of the magnesium alloy. The micro composite coating layer, prepared by the method, has better protective thickness, good binding force with the matrix, good corrosion resistance, high hardness, good surface brightness and full luster, effectively solves the protective requirements of high wear resistance and corrosion resistance of the magnesium alloy, and provides powerful guarantee to the further application of the magnesium alloy.

Description

technical field [0001] The invention relates to the technical field of metal surface treatment, in particular to a method for preparing a micro-arc oxidation-composite electroless nickel coating on the surface of a magnesium alloy. Background technique [0002] Magnesium alloy is the metal with the lowest density among metal structural materials. Compared with aluminum alloy, it has a large elastic modulus, good heat dissipation, good shock absorption, and large impact load capacity. The metal structure material with the most potential for performance optimization development is also one of the most promising metal materials in the 21st century. In addition, magnesium alloy also has superior properties such as high specific strength, high specific stiffness, good damping, good thermal conductivity and good vibration damping. As a substitute for steel, aluminum, plastic and other materials, it is widely used in the automotive industry, aerospace industry and electronics. Ind...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F17/00C25D11/30C23C18/36
Inventor 杜克勤郭兴华郭泉忠王勇王福会
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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