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Chromate-free passivator and method for passivating aluminum or aluminum alloy surface

A chromium-free passivator and mixture technology, which is applied in the coating process of metal materials, can solve the problems of poor passivation film quality and low paint film adhesion, and achieve improved anti-corrosion performance, improved wet film adhesion, The effect of excellent binding ability

Inactive Publication Date: 2017-05-31
LANZHOU UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the effects of these chromium-free passivators are not ideal, and the formed passivation film is often of poor quality and the paint film adhesion is low

Method used

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  • Chromate-free passivator and method for passivating aluminum or aluminum alloy surface

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preparation example Construction

[0030] The present invention has no special limitation on the preparation method of the chromium-free passivating agent, and the technical scheme for preparing the composition well-known to those skilled in the art can be adopted. In the present invention, the preparation method of the chromium-free passivating agent is preferably mixing the raw materials described in the above technical scheme, more preferably comprising the following steps:

[0031] The accelerator is mixed with the first part of water to obtain an accelerator solution;

[0032] The accelerator solution is sequentially mixed with a modified water-soluble resin, a coupling agent and a nano-inorganic material to obtain a mixed material liquid;

[0033] Under the condition of stirring, the remaining water is added to the mixed material liquid.

[0034]In the present invention, the stirring rate is preferably 300-500 r / min, more preferably 350-450 r / min; the stirring time is preferably 10-30 min, more preferabl...

Embodiment 1

[0051] Prepare passivation solution according to the formula of chromium-free passivator, the content of each component in the passivator is: water 829kg, organosilicon modified acrylic resin 150.0kg (solid content 20wt%, weight average molecular weight 15000), KH-5605.0 kg, nano-titanium dioxide 3.0kg, phytic acid 8.0kg, nitric acid 5.0kg;

[0052] First, add nitric acid and phytic acid into 500.0kg of water, after stirring evenly, add organic silicon-modified acrylic resin, KH-560 and nano-titanium dioxide in turn, and then add the remaining water under the condition of stirring, and stir evenly;

[0053] Mix the above-mentioned passivating agent with the passivation bath solution according to the concentration of 1% and 10% by mass, and set aside;

[0054] Use sulfuric acid and hydrofluoric acid to prepare a degreasing solution, control the free acid value in the degreasing solution to about 15, immerse the standard aluminum alloy test panel (10×20cm) in the degreasing solu...

Embodiment 2

[0059] Prepare passivating solution according to the formula of chromium-free passivating agent, the content of each component in the passivating agent is: water 829.0kg, organosilicon modified acrylic resin 100kg (solid content 25wt%, weight-average molecular weight 10000), waterborne polyurethane 50kg (solid content 30%, weight average molecular weight 25000), KH-792 5kg, nano titanium dioxide 3kg, phytic acid 8kg, nitric acid 5kg, acetic acid 3kg;

[0060] Add nitric acid, phytic acid and acetic acid into 500kg of water according to the above-mentioned addition amount, after stirring evenly, add KH-792, silicone modified acrylic resin, water-based polyurethane and nano-titanium dioxide in sequence, and then add the remaining water under the condition of stirring, and stir Evenly enough;

[0061] Mix the above-mentioned passivating agent with a passivating bath solution at a concentration of 1% by mass, and set aside;

[0062] Degrease and wash the standard aluminum alloy t...

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Abstract

The invention provides a chromate-free passivator. The chromate-free passivator comprises the following components in a percent by weight: 77.3-93.8% of water, 5.0-20.0% of water-soluble resin, 0.1-1.0% of a coupling agent, 0.2-0.5% of a nanometer inorganic material, 0.5-1.0% of a complexing agent and 0.1-0.5% of an accelerant. When the chromate-free passivator provided by the invention is applied to the passivation of an aluminum or aluminum alloy surface, an obtained passivating film has excellent corrosion resistance and excellent bonding capability with a paint film and a powdery coating on the surface of a base material. Experimental results show that the corrosion resistance of the aluminum or aluminum alloy surface which is treated by using the chromate-free passivator is improved, the passivating film can resist salt mist for more than 72 hours, the wet film adhesion force of the paint film is improved, pressure cooker boiling can be withstood for more than two hours, and the quality of the formed film cannot be affected by environmental factors. The operation is simple, and the chromate-free passivator is suitable for site use.

Description

technical field [0001] The invention relates to the technical field of metal surface treatment, in particular to a chromium-free passivator and a method for passivating the surface of aluminum or aluminum alloy. Background technique [0002] Aluminum and its alloys have the characteristics of low density, low cost, high mechanical strength, excellent thermal conductivity, strong electrical conductivity, easy processing and easy recycling, and are widely used in various industries. However, aluminum and its alloys have long been subjected to harsh conditions. When affected, its corrosion resistance will be significantly reduced. Passivation treatment on the metal can form a layer of fine-grained film on its surface, which can greatly improve the corrosion resistance of the metal. [0003] In the surface treatment measures of aluminum and aluminum alloys, hexavalent chromate treatment technology has been widely used. The strong oxidation of chromate is used to form a passive ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/56C23C22/07
CPCC23C22/07C23C22/56C23C2222/20
Inventor 张定军陈玉娴白雪瞿朝云李永通甘明洋王海燕马应霞
Owner LANZHOU UNIVERSITY OF TECHNOLOGY
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