A Two-step Micro-arc Oxidation Method for Forming Super Wear-resistant Coating on Aluminum Alloy Surface

Abstract

The invention relates to the field of electrochemistry, and discloses a two-step micro-arc oxidation method for forming a super wear-resistant coating on the surface of an aluminum alloy. The method uses an aluminum alloy as a substrate and a low-concentration and high-concentration aluminate solution as a medium respectively. , through two-step micro-arc oxidation to quickly generate a dense single-layer alumina layer, in which the corundum (α-Al2O3) component reaches more than 40%. The micro-arc oxidation time only needs 8-10 minutes to form a film of about 40-50 microns. Nano-indentation experiments show that the hardness of the outer layer of the oxide film is close to the theoretical hardness of α-Al2O3 (26Gpa). The film layer has excellent wear resistance. For a film layer with a thickness of about 45 microns, under the condition of ball-block dry friction, the load is 80? The film layer was only slightly worn (the depth of the wear scar was about 12 microns) after rubbing for 30 minutes under the N condition, while the silicate micro-arc oxidation film as a comparison, at a load of 80? Under the N condition, the film layer was worn through after rubbing for 5 minutes, and the depth of the wear scar reached 109 microns.

Description

technical field [0001] The invention relates to the field of electrochemistry, in particular to a two-step micro-arc oxidation method for forming a super wear-resistant coating on the surface of an aluminum alloy. Background technique [0002] Aluminum is the most abundant metal element in the earth's crust, and it is also a type of metal element closely related to people. Various types of deformed aluminum alloys are used in space shuttles, missiles, cars, and mobile phone cases. Aluminum and its aluminum alloys have the advantages of high specific strength, good thermal and electrical conductivity, strong reflective properties, beautiful color, non-magnetic, good corrosion resistance, good plasticity and formability, and no low-temperature brittleness. non-ferrous metal materials. [0003] Aluminum and its aluminum alloys are widely used in various sectors of the country's economy due to their excellent properties, and have become the second largest metal material after s...

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Problems solved by technology

[0010] 1. At present, the micro-arc oxidation of aluminum alloys at home and abroad mostly uses silicate as the electrolyte, and the corundum (α-Al 2 o 3 ) composition is low, and other impurity components with lower hardness (such as mullite) will be introduced into the film layer

[0011] 2. At present, the micro-arc oxidation treatment of most aluminum alloys at home and abroad is a low-concentration electrolyte, and the film-forming speed is slow

[0012] 3. The film layer obtained in low-concentration electrolyte (whether it is silicate or aluminate) has a double-layer structure, and there are large-sized holes in the inner and outer layers, which affects the wear resistance of the film layer

[0013] 4. The problem that aluminum alloys cannot be formed into films by conventional methods in high-concentration aluminate solutions

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