Aluminum or aluminum alloy protection chromium-free passivation solution, preparation method and aluminum or aluminum alloy surface protection method thereof

Abstract

The invention relates to an aluminum or aluminum alloy protection chromium-free passivation solution, a preparation method and an aluminum or aluminum alloy surface protection method thereof. According to the passivation solution, a silane coupling agent serves as a silicon source; an inorganic salt aqueous solution of rare earth ions serves as a hydrolysis accelerant. The organic-inorganic hybridized passivation solution free of chromium or fluorine or other toxic substances is prepared by adding an organic inhibitor. A hybrid film on the treated surface of aluminum alloy has the characteristics of being compact, uniform and high in corrosion resistance. The chromate process can be replaced. In addition, the adhesive force between the surface of the aluminum alloy and a coating can be improved.

Description

technical field [0001] The invention relates to a chromium-free passivation solution for aluminum or aluminum alloy protection, a preparation method and an aluminum or aluminum alloy surface protection method, belonging to the technical field of metal surface protection. Background technique [0002] Due to the advantages of low density, high specific strength, corrosion resistance, good thermal conductivity, fast heat transfer, good formability and low cost, aluminum alloy is widely used in the construction industry, chemical industry, aerospace, mechanical electronics, transportation, etc. and other fields have a wide range of applications. [0003] Under natural conditions, a thin layer of oxide film will be formed on the surface of aluminum alloy, but this layer of oxide film is loose, porous, uneven and discontinuous, and has poor corrosion resistance in atmospheric environment or various corrosive media conditions, so it cannot be used as aluminum alloy. Surface prote...

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Problems solved by technology

Hexavalent chromate treatment technology is currently the most widely used and mature aluminum surface treatment technology, but the strong carcinogenic effect of hexavalent chromium ions is extremely harmful to the human body and the environment, so a low-cost, environmentally friendly, Materials and production processes that are chromate-free and have better corrosion resistance than chromate have become the hot and difficult points of current research

However, in further research, it was found that the rare earth conversion coating produced in practical applications is mainly deposited by solid particles of rare earth compounds, and the film quality is not uniform, and when the film reaches a certain thickness, it becomes fluffy, resulting in a decline in its anti-corrosion ability , the adhesion is not strong, which greatly limits the wide application of rare earth treatment in industry

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