Method for sealing aluminum alloy anodic oxide film pores through using silica sol

Abstract

A method for sealing aluminum alloy anodic oxide film pores through using a silica sol comprises the following steps: properly pre-treating aluminum or an aluminum alloy, and carrying out anodic oxidation treatment through a routine technology; and treating the aluminum or the aluminum alloy subjected to the anodic oxidation treatment through electrophoresis under different process conditions, carrying out electrophoretic deposition, drying, and sintering to seal the aluminum and aluminum alloy anodic oxide film pores and simultaneously generate a silicon oxide ceramic coating. The method using the electrophoretic deposition provided in the invention has the advantages of simple process, easy enforcement, and no need of high condition requirements, and the prepared ceramic coating has the advantages of compactness, good performances, and component uniformity. The method can be used for sealing the aluminum or aluminum alloy anodic oxide film pores, and the electrophoretic silica sol method applied to the anodic oxide film pores has the characteristics of cleanness, no pollution, and easy industrialization realization.

Description

technical field [0001] The present invention relates to a method for sealing the micropores of aluminum or aluminum alloy and parts containing aluminum after anodic oxidation, in particular to a method for sealing the pores of aluminum alloy anodic oxidation film with silica sol, which can be passed under the condition of low voltage Seal the hole several times to achieve a better sealing effect. Background technique [0002] Due to the advantages of high specific strength, good thermal and electrical conductivity, and light weight, aluminum and its aluminum alloys have broad application prospects in modern industries such as aerospace, construction, and automobiles. However, aluminum alloys are soft, have poor wear resistance, and are easily corroded. The nature of aluminum is relatively active, and the oxide film formed on the surface in the air has certain corrosion resistance, but the thickness of this oxide film is only a few nanometers to tens of nanometers, the hardn...

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Problems solved by technology

However, the aluminum alloy is soft, has poor wear resistance, and is easily corroded.

The nature of aluminum is relatively active, and the oxide film formed on the surface in the air has certain corrosion resistance, but the thickness of this oxide film is only a few nanometers to tens of nanometers, the hardness is also very low, and the ability to resist environmental erosion is poor.

Therefore, the necessary surface strengthening treatment is often carried out before use. Aluminum and its alloys are placed in an appropriate electrolyte as the anode for electrification treatment. Under the action of an external electric field, an oxide film can be formed on the surface of the aluminum product. The thickness is between 10-200um, its corrosion resistance, wear resistance, and electrical insulation are greatly improved, which greatly broadens the application range of aluminum and its alloy materials, but the porous film obtained by anodizing aluminum alloy - the oxidation process produces The oxide film has high porosity and adsorption capacity, and is easily corroded by polluted and corrosive media, especially aggressive anions (such as Clˉ, S 2 ˉ, containing cations, etc.) and water molecules can still pass through the oxide film, resulting in poor corrosion resistance (especially small hole corrosion) and wear resistance. Therefore, sealing treatment must be performed to improve its corrosion resistance and corrosion resistance. Pollution ability and ability to fix chromophores