Zinc-aluminum-magnesium alloy self-repairing chromium-free passivator as well as preparation method and application thereof

Abstract

The invention relates to the technical field of metal surface treatment chemicals, and provides a zinc-aluminum-magnesium alloy self-repairing chromium-free passivator as well as a preparation method and application thereof. The chromium-free passivator comprises 10-15 parts of anionic acrylic acid modified epoxy resin, 5-30 parts of modified alkaline silica sol, 3-5 parts of nanoscale hydroxyl graphene sol, 5-10 parts of silicate, 3-5 parts of zinc nitrate, 5-10 parts of sodium tungstate, 0.05-2 parts of soluble aluminum salt, 1-3 parts of ceric sulfate, 20-40 parts of a film forming accelerant, 2-8 parts of a stabilizer, 4-8 parts of a pH regulator, 2-6 parts of an oxidizing agent, and the balance water. A zinc-aluminum-magnesium alloy treated by the chromium-free passivator has bright appearance, and the passivated zinc-aluminum-magnesium alloy has excellent corrosion resistance, humidity and heat resistance and weather resistance; and the prepared chromium-free passivator is environmentally friendly, can replace a traditional hexavalent chromium passivator, is expected to be widely applied to the zinc-aluminum-magnesium industry, and has great industrial value and social value.

Description

technical field [0001] The invention relates to the technical field of metal surface treatment chemicals, in particular to a zinc-aluminum-magnesium alloy self-repairing chromium-free passivator and its preparation method and application. Background technique [0002] Hot-dip galvanizing is to make the molten metal react with the iron substrate to produce an alloy layer, so that the substrate and the coating are combined. Hot-dip galvanized steel has the advantages of uniform coating, strong adhesion, long service life, simple manufacturing process, and low product price. It is increasingly demanded in many different industries such as automobile industry, electrical industry and construction industry. In order to improve the corrosion resistance of hot-dip galvanized steel, zinc-alloy coated steel, including zinc-aluminum-magnesium-coated steel, is produced by adding elements such as magnesium and aluminum to pure zinc-coated steel. [0003] Zinc-aluminum-magnesium-coated ...

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Problems solved by technology

However, because Cr(Ⅵ) is harmful to the environment and the human body, the use of chromate is strictly restricted at home and abroad.

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