Method for performing chromium-free hole sealing treatment on micro-arc oxidation film on surface layer of aluminum alloy

Abstract

A method for performing chromium-free hole sealing treatment on a micro-arc oxidation film on an aluminum alloy surface layer comprises the following steps: respectively weighing alcohol, a KH-550 silane coupling agent and distilled water according to a mass ratio of 1: (2-3): (6-10), firstly adding the alcohol into the distilled water, fully stirring, then slowly dropwise adding the KH-550 silane coupling agent, adjusting the pH value to 3-6 by using glacial acetic acid, and hydrolyzing at normal temperature for 20-80 hours to obtain a hole sealing solution; an aluminum alloy sample piece with the micro-arc oxidation film on the surface layer is put into the hole sealing solution to be soaked for 5-60 min and then put into a drying box to be cured at the constant temperature of 150-200 DEG C, chromium-free hole sealing treatment is completed, the surface of the micro-arc oxidation film layer is covered with an organic siloxane film, corrosion induction at the oxidation film / base body interface is inhibited, direct contact between a corrosion medium and a base body is prevented, and the chromium-free hole sealing treatment is completed. Meanwhile, the characteristics of high hardness, high wear resistance, electrical insulation and the like of the micro-arc oxidation film are reserved, the process is simple, the treatment time is short, control is easy and convenient, the hole sealing solution can be repeatedly used, and waste water and waste residues containing heavy metal ions cannot be generated.

Description

technical field [0001] The invention relates to the field of micro-arc oxidation films on the surface of aluminum alloys, in particular to a method for performing chromium-free sealing treatment on the micro-arc oxidation films on the surface of aluminum alloys. Background technique [0002] With the development of marine resources and the emergence of a new pattern of international strategies, the research and development of high-performance structural materials for marine engineering has become one of the hot issues in material research. Aluminum alloys are widely used in the fields of ships and ocean engineering because of their light weight, high specific strength, and low temperature resistance. However, the aluminum alloy itself has disadvantages such as low hardness, poor wear resistance, and poor corrosion resistance, which greatly limit the application of aluminum alloys in marine environments. Although the surface can naturally form an oxide film, the film thickne...

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Problems solved by technology

[0003] The sealing process can make up for the structural defects of the film layer while retaining the high hardness and high wear resistance of the micro-arc oxidation film. At present, most of the aluminum materials are surface treated by hydration sealing or room temperature metal salt sealing, which is resistant to corrosion environments. Next, the dichromate sealing technology is adopted. The discharge of nickel salts and chromium salts in the sealing solution seriously endangers the environment, which not only causes high wastewater treatment costs for enterprises, but also has a relatively large adverse impact on environmental protection.

Therefore, there is currently a lack of nickel-free sealing technology that can be put into industrial applications. The main reason is that it is difficult to ensure that the comprehensive sealing quality and performance of aluminum anodic oxide films meet the requirements while achieving environmental protection.

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