A chrome-free passivation solution

Abstract

The invention discloses a non-chrome purified liquid. Components of each 1000kg of the non-chrome purified liquid include: 400-900kg of deionized water, 100-500kg of low molecular weight alcohol, 50-200kg of zirconium-fluoride-acid (salt) type sedimentary inorganic film-forming agent, 10-100kg of organic-acid type metal activator, 100-300kg of silane hydrolyzate and 5-20kg of high-temperature-resistant inorganic antioxidant. The non-chrome purified liquid is good in corrosion resistance, has good high-temperature and xanthochroia resisting features since the high-temperature-resistant inorganic antioxidant is added in without organic aqueous resin, is adaptable to surface passivation processing of galvanized and aluminum-zinc alloy plated type metal products, and is further adaptable to surface passivation processing of galvanized plates (the galvanized plates for computer cases and the like) with special requirements for high-temperature and xanthochroia resisting features.

Description

technical field [0001] The invention belongs to the technical field of chromium-free passivation, and in particular relates to a chromium-free passivation solution with high-temperature yellowing resistance. Background technique [0002] The method of surface galvanizing to protect the base metal can significantly reduce the corrosion of ferrous metals in the iron and steel industry. About half of the zinc produced in the world is used in the galvanizing process, because the galvanized sheet has good corrosion resistance and is relatively cheap It is widely used in aviation, automobiles, building materials, home appliances, machinery and other fields, and it has also become one of the fastest-growing steel varieties in my country in recent years. [0003] The chemical properties of zinc are lively, and it is easy to oxidize and darken in the atmosphere, and finally produce "white rust" corrosion. After galvanizing, it is treated with a passivation solution to cover a layer o...

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Problems solved by technology

[0010] Chinese patent CN02815757.5 (the title of the invention is "Chromium-free passivation method for zinc and zinc alloy") discloses a chromium-free composition, which belongs to passive inorganic passivation, and is composed of titanium ions, fluorides and oxidants. It can be used for passivation treatment on the surface of zinc layer, but it forms a blue inorganic conversion film

In addition, because the final system is acidic, the use of silicone acrylic emulsion will cause a tendency to decrease the stability of the system

[0012] Chinese patent CN00114178.3 (the title of the invention is "Chromium-free passivation solution for protecting galvanized layer and its coating method") discloses a chromium-free passivation solution, which is composed of water-based acrylic resin and molybdate , the pH value of the system is 6~9, which can ensure the stability of the passivation solution system, but the corrosion resistance is still average and cannot meet the requirements of actual working conditions

More importantly, the passivation film is a "colored passivation film with more light blue and green" rather than a colorless film, which cannot meet the requirements of maintaining the bright white color of the galvanized layer after passivation, which will limit the quality of the passivation solution. Application in hot-dip galvanized layer

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