Corrosion-resistant neutral chrome-free coating agent and preparation method thereof

Abstract

The invention belongs to the technical field of chemicals, and relates to a metal surface treatment technology, in particular to a corrosion-resistant neutral chrome-free coating agent and a preparation method thereof. The corrosion-resistant neutral chrome-free coating agent comprises the following components of, by weight, 2-10 parts of water soluble resin, 2-10 parts of micromolecule solvents,10-30 parts of nano oxide sol, 0-5 parts of film-forming auxiliary agents, 1-10 silane coupling agents, 0-5 parts of pH conditioning agents and 50-70 parts of water. The corrosion-resistant neutral chrome-free coating agent is convenient to apply, and is directly in contact with aluminum, magnesium and an aluminum-magnesium alloy plate at ordinary temperature, so that the magnesium-aluminum alloyplate which is high in corrosion resistance, acid resistance and alkali resistance and reaches the hardness requirement can be produced. Aluminum and magnesium alloys using the corrosion-resistant neutral chrome-free coating agent have no color change in the surfaces, and a self-colored passive film can be obtained; and a film layer is thin, and the corrosion-resistant neutral chrome-free coatingagent has little impedance to a metal base and has no corrosion and the subsequent serviceability of the metal base is not affected.

Description

technical field [0001] The invention relates to metal surface treatment technology. Specifically, the invention relates to a corrosion-resistant neutral chromium-free coating agent and a preparation method thereof, belonging to the technical field of chemicals. Background technique [0002] Aluminum alloy refers to the general term for alloys based on aluminum. The main alloying elements are copper, silicon, magnesium, zinc, and manganese, and the secondary alloying elements are nickel, iron, titanium, chromium, lithium, etc. Aluminum alloy is the most widely used non-ferrous metal structural material in industry, and has been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding and other aluminum alloys. [0003] However, aluminum alloys are prone to pitting corrosion, crevice corrosion, stress corrosion and corrosion fatigue when used in humid, industrial gas, fuel gas, salt and dust atmospheres, which limit their application range and shor...

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Problems solved by technology

[0005] Wang Shuanghong et al. (Material Protection, 2011, 44(5): 59-61) reported a nano-ceramic treatment agent, the nano-ceramic ZrO 2 The conversion coating enhances the adhesion between the substrate and the epoxy resin paint layer and polyurethane paint layer, which meets the painting requirements, but the salt spray test is not high

Organic matter passivation is mainly composed of water-soluble acrylic resin or silane coupling agent, such as Chinese patent publication number CN 1268583, but the corrosion resistance of the film is poor

Liu Yongping (Materials Protection, 2011, 46(5): 62-63) pretreated hot-dip galvanized steel sheet with silane KB-175, which can improve its bonding force with epoxy resin coating, but neutral salt The results of the fog test show that the corrosion resistance of the silane film and the phosphating film is quite different, which cannot meet the requirements of corrosion resistance

[0006] In summary, although researchers have developed a variety of chromium-free passivators, their corrosion resistance is far from that of the original chromate passivation film.

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