Corrosion-resistant magnesium aluminum alloy chromium-free passivation solution

Abstract

The invention discloses a corrosion-resistant magnesium aluminum alloy chromium-free passivation solution, which comprises the following components: 10-40 parts of water-base resin, 1-10 parts of nanoparticle sol, 1-10 parts of fluoric-containing acid, 1-5 parts of fluoric acid-containing salt, 1-5 parts of a rare earth catalyst, 1-10 parts of a silane coupling agent, 1-5 parts of a corrosion inhibitor, 1-2 parts of a complexing agent and 40-70% of water. The corrosion-resistant magnesium aluminum alloy chromium-free passivation solution does not contain chromium and other toxic and harmful substances, meets the ROHS environmental protection law of the European Union, and meanwhile, can form an organic and inorganic composite passivation film and a thin film on the surface of a magnesium aluminum layer, and the formed composite passivation film has an excellent physical property and corrosion resistance, and has higher corrosion resistance and long salt fog time, so that the corrosion resistance of a magnesium aluminum alloy plate is better improved.

Description

technical field [0001] The invention relates to metal surface treatment technology, in particular to a corrosion-resistant magnesium-aluminum alloy chromium-free passivation solution. Background technique [0002] Magnesium-aluminum and its alloys are mainly divided into Mg-Al-Mn series, Mg-Al-Zn-Mn series, Mg-Al-Si-Mn series, and Mg-Al-RE series according to different components. The density of magnesium-aluminum alloy is small, which is about 2 / 3 of the density of aluminum. It has high specific strength and specific stiffness, as well as strong shock absorption, strong anti-electromagnetic interference ability, good dimensional stability and machinability. , electrical and thermal conductivity, etc., and have received widespread attention in many fields such as automobiles, electronic appliances, and aviation. [0003] However, magnesium-aluminum alloys are prone to pitting corrosion, crevice corrosion, stress corrosion and corrosion fatigue when used in humid, industrial...

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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

[0006] 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

[0007] 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.

Therefore, so far, there is still no corrosion resistance of a corrosion-resistant magnesium-aluminum alloy chromium-free passivation solution that satisfies people, and it is difficult to meet the requirements of users.

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