Method for improving acid salt spray corrosion resistance of zinc coating

A technology of salt spray corrosion and galvanized layer, which is applied in the direction of metal material coating process, etc., can solve the problems of poor corrosion resistance, great difference in corrosion resistance of galvanized layer, lack of etc., and achieve excellent corrosion resistance, Good binding force and uniform color effect

Active Publication Date: 2021-10-01
CHENGDU AIRCRAFT INDUSTRY GROUP +1
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  • Abstract
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  • Claims
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AI Technical Summary

Problems solved by technology

[0009] At present, although there are many reports on the passivation of trivalent chromium applied to the galvanized layer, the corrosion resistance of the galvanized layer after passivation varies greatly, and the overall corrosion resistance in the acidic environment is not good.
However, at present and in the future, galvanized components will be more and more used in the marine environment. The humid and hot characteristics of the marine environment put forward higher requirements for the acid and salt spray corrosion resistance of the galvanized layer. At present, there is no effective solution for this. Improvement means

Method used

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  • Method for improving acid salt spray corrosion resistance of zinc coating

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Embodiment 1

[0036] A method for improving the acid salt spray corrosion resistance of galvanized coating, comprising the following steps:

[0037] 1) Chemical degreasing. Prepare a chemical degreasing solution with 30g / L sodium hydroxide, 45g / L sodium carbonate, and 25g / L sodium silicate; put the Q235 steel sheet in the chemical degreasing solution at 50-70°C for 5-15 minutes. After the parts are degreased, they are thoroughly washed with warm water. It is necessary to ensure that the surface of the entire part is hydrophilic. If the continuous water film lasts for more than 60 seconds, the degreasing is considered qualified.

[0038]2) activation. The sample treated in step 1) is subjected to activation treatment, and the process parameters are: 50-100 g / L hydrochloric acid, 40-50 g / L urotropine, soaking at room temperature for 1-2 minutes. After activation, the samples were thoroughly washed with deionized water.

[0039] 3) Neutralization. The samples treated in steps 1) and 2) wer...

Embodiment 2

[0051] A method for improving the acid salt spray corrosion resistance of galvanized coating, comprising the following steps:

[0052] 1) Chemical degreasing. Prepare a chemical degreasing solution with 30g / L sodium hydroxide, 45g / L sodium carbonate, and 25g / L sodium silicate; put the Q235 steel sheet in the chemical degreasing solution at 50-70°C for 5-15 minutes. After the parts are degreased, they are thoroughly washed with warm water. It is necessary to ensure that the surface of the entire part is hydrophilic. If the continuous water film lasts for more than 60 seconds, the degreasing is considered qualified.

[0053] 2) activation. The sample treated in step 1) is subjected to activation treatment, and the process parameters are: 50-100 g / L hydrochloric acid, 40-50 g / L urotropine, soaking at room temperature for 1-2 minutes. After activation, the samples were thoroughly washed with deionized water.

[0054] 3) Neutralization. The samples treated in steps 1) and 2) we...

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Abstract

The invention discloses a method for improving acid salt spray corrosion resistance of a zinc coating. The method comprises the following steps of sequentially carrying out pretreatment, alkaline zinc plating, bright dipping treatment, trivalent chromium passivation treatment, air stop treatment, water-based silica sol sealing treatment and vacuum drying treatment on a part, so that an excellent colored passivation film which is good in binding force, uniform in color distribution and good in acid resistance and salt spray corrosion resistance is prepared on the surface of the zinc coating of the part, and a neutral salt spray test of 1440 h or above and an acid salt spray test of 864 h or above can be past. By meas of the method, a novel trivalent chromium passivation technology and water-based silica sol sealing composite treatment are adopted, the corrosion resistance of the zinc coating in the acid salt mist environment is greatly improved, the technology is green and environmentally friendly, waste water treatment is simple, and good practicability is achieved.

Description

technical field [0001] The invention belongs to the technical field of metal surface passivation treatment, and in particular relates to a method for improving the acid salt spray corrosion resistance of a galvanized layer. Background technique [0002] Galvanizing is the most cost-effective method of protecting steel. However, the zinc layer interacts with CO in the air in a humid environment 2 , O 2 A layer of white corrosion product is formed on the surface, which affects the appearance and corrosion resistance of the zinc layer. Therefore, passivation treatment is often required after galvanizing to improve its appearance and corrosion resistance. [0003] At present, the passivation process can be divided into hexavalent chromate passivation, trivalent chromium passivation and chromium-free passivation according to the composition of passivation solution. The traditional chromate passivation process is mature and has self-healing ability, but hexavalent chromium, wh...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/22C25D5/52C25D5/48C23C22/53C23C22/83
CPCC25D3/22C25D5/52C25D5/48C23C22/53C23C22/83
Inventor 吕玲王力强王利华仲星屹梁鑫廖广其詹中伟张骐孙志华
Owner CHENGDU AIRCRAFT INDUSTRY GROUP
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