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Anticorrosive and wear-resistant low density composite structure coating on surface of magnesium alloy, and production method thereof

An anti-corrosion and wear-resistant composite structure technology, applied in the field of material engineering, can solve problems such as poor wear resistance, harmful emissions, and low hardness of dense coatings, and achieve the effect of improving corrosion resistance and wear resistance

Pending Publication Date: 2018-09-21
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above methods can improve the corrosion resistance of magnesium alloys to a certain extent, and some hard coatings can also improve the wear resistance of the surface, but there are still the following problems: a) The inherent defects of the coating cause it to only slow down the corrosion and not Can not completely isolate the corrosive medium; b) Most of the solution-based methods have problems with harmful emissions and waste liquid treatment, which is contrary to the concept of green development
However, the dense coatings of aluminum and aluminum alloys have extremely low hardness, poor wear resistance, and are easily worn away to cause the magnesium alloy to be re-exposed, thus failing to play a role in corrosion protection.

Method used

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  • Anticorrosive and wear-resistant low density composite structure coating on surface of magnesium alloy, and production method thereof
  • Anticorrosive and wear-resistant low density composite structure coating on surface of magnesium alloy, and production method thereof
  • Anticorrosive and wear-resistant low density composite structure coating on surface of magnesium alloy, and production method thereof

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preparation example Construction

[0038] A method for preparing a corrosion-resistant and wear-resistant low-density composite structural coating on the surface of a magnesium alloy disclosed by the invention comprises the following steps:

[0039] First, under the synergistic effect of powder preheating and higher cold spraying parameters or by introducing in-situ micro-forging effect during the spraying process, high-density pure aluminum is prepared on the surface of magnesium alloy substrates using low-cost nitrogen or compressed air. or aluminum alloy coating;

[0040] Secondly, the high-density pure aluminum or aluminum alloy coating on the surface of the magnesium alloy substrate is subjected to anodic oxidation treatment or micro-arc oxidation treatment, and part of the pure aluminum or aluminum alloy coating is converted into a high-hardness aluminum oxide coating. In this way, a double-layer composite structure coating with a high-density pure aluminum or aluminum alloy coating as the bottom layer an...

Embodiment 1

[0043] Pure aluminum with a particle size of 5-35 μm is used as spray powder, and 410 martensitic stainless steel particles with a particle size of 150-250 μm are used as micro-forged particles, and their shapes are as follows: figure 1 Shown in (a) and (b). During the spraying process, the pure aluminum powder and the micro-forged particles are sent to the cold spray gun and the micro-forged spray gun at a volumetric powder feed rate of 1:1, and the outlet of the spray gun is adjusted so that the two powder streams cover the same area.

[0044] Before spraying, use 40# brown corundum sand for the AZ31B magnesium alloy substrate, and perform sandblasting roughening on the surface of the substrate under the condition of compressed air pressure of 0.6MPa, so that the roughness can reach Ra 1.0-4.0.

[0045] With nitrogen as the accelerating gas, the gas temperature is 240°C, the main gas pressure is 2.0MPa, the powder feeding rate is 2.6g / min, the spray gun moving speed is 40mm / ...

Embodiment 2

[0051] Use 6061 aluminum alloy powder with a particle size of 20-65 μm as the spray powder, such as Figure 6 shown. Before spraying, use 40# brown corundum sand for the AZ91D magnesium alloy substrate, and perform sandblasting roughening on the surface of the substrate under the condition of compressed air pressure of 0.6MPa, so that the roughness can reach Ra 5.7 microns.

[0052] Nitrogen is used as the accelerating gas, the gas temperature is 460°C, and the main gas pressure is 5MPa. A cold spray gun with a 250mm powder preheating section at the rear end of the spray gun is used to preheat the powder to above 350°C at a relatively low gas velocity. The powder feeding rate is 30g / min, the spray gun moving speed is 200mm / s, and the spraying distance is 20mm, under the parameter conditions, a high-density 6061 aluminum alloy coating with a thickness of about 400μm is deposited. Use a sulfuric acid concentration of 180g / L and a current density of 2 and 5A / dm 2 , the temperat...

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Abstract

The invention discloses an anticorrosive and wear-resistant low density composite structure coating on the surface of a magnesium alloy, and a production method thereof. The composite structure coating comprises an anticorrosive bottom layer and a wear-resistant top layer which are sequentially arranged on the surface of the magnesium alloy from bottom to top, the anticorrosive bottom layer is a high-density aluminum layer or aluminum alloy layer, and the wear-resistant top layer is a high-hardness alumina ceramic layer. The high wear resistance of the surface of the magnesium alloy is realized by means of the high-hardness alumina top layer, and the great improvement of the corrosion resistance of the magnesium alloy substrate is realized by the physical isolation effect of the high-density aluminum or aluminum alloy coating and the top alumina layer to a corrosion medium in order to finally achieve the corrosion and wearing dual protection effects of the magnesium alloy substrate. The production method makes the low-cost production of a magnesium alloy protection layer with anticorrosion and wear resistance dual characteristics become possible, and the residual compressive stressin the aluminum and aluminum alloy coating can delay the generation and cracking of cracks under a periodical load condition and improve the fatigue life of the magnesium alloy, so the application field of the magnesium alloy is significantly expanded.

Description

technical field [0001] The invention belongs to the technical field of material engineering, and in particular relates to an anti-corrosion and wear-resistant low-density composite structural coating on the surface of a magnesium alloy and a preparation method thereof. Background technique [0002] Magnesium alloy is the metal structure material with the smallest density so far. It has high specific strength and specific stiffness, good thermal and electrical conductivity, excellent damping and shock resistance (attenuation coefficient is more than ten times that of aluminum alloy), and super electromagnetic shielding As well as the ability to resist the penetration of high-energy particles, it is a strategic material with great development potential in the fields of aerospace, aviation, weapon industry, nuclear industry, automobile and medical treatment. With the development of new magnesium alloys, the purification of harmful elements for corrosion, the optimization of met...

Claims

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Application Information

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IPC IPC(8): C23C24/08C23C28/00C25D11/08
Inventor 雒晓涛张越李长久
Owner XI AN JIAOTONG UNIV
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