Composite passivation solution for mechanical zinc coating

A technology of mechanical galvanizing and passivation solution, applied in coating, metal material coating process, polyurea/polyurethane coating, etc., can solve the unfavorable popularization and use of inorganic passivating agent, high cost of film-forming agent, human body and environment. Harm and other problems, to achieve the effect of good passivation, long salt spray resistance and low cost

Inactive Publication Date: 2014-10-22
SHANDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it is very difficult to treat the waste liquid after chromate passivation, and the waste liquid contains toxic hexavalent chromium, which is very harmful to human body and environment.
Although the existing inorganic passivators on the market do not contain chromium and do not have the pollution problem of hexavalent chromium, their film-forming effect is poor, their stability is poor, and their passivation effect is not good.
Although film-forming agents can be added to promote film-forming and improve film-forming effects, the price of film-forming agents is expensive, and the preparation process is cumbersome, which is not conducive to the popularization and use of inorganic passivators.

Method used

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  • Composite passivation solution for mechanical zinc coating
  • Composite passivation solution for mechanical zinc coating

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 1. Raw materials and contents for preparing composite passivation solution:

[0021] Cationic water-based polyurethane 8g, sodium molybdate 3g, titanium sulfate 0.1g, sodium silicate 1.5g, cerium nitrate 2.5g, benzotriazole 0.1g, phytic acid 1.5g, deionized water 83.3g.

[0022] 2. The preparation method is as follows: after mixing the above raw materials, adjust the pH value of the aqueous solution to 8 by using sulfuric acid with a mass fraction of 98%.

[0023] Take plate A and conduct the following tests:

[0024] (1) Detection of hexavalent chromium content

[0025] According to GB / T 9758.5-1988 "Determination of "Soluble" Metal Content in Paints and Varnishes Part 5: Determination of Hexavalent Chromium Content in Pigment Part of Liquid Paints or Powder Paints by Diphenylcarbazide Spectrophotometric Method" Soluble hexavalent chromium content detection.

[0026] (2) Neutral salt spray corrosion test (NSS)

[0027] The FQY025 salt spray chamber is used, accordi...

Embodiment 2

[0038] Except following difference, other is with embodiment 1.

[0039] 1. Raw materials and contents for preparing composite passivation solution:

[0040] Anionic water-based polyurethane 10g, sodium molybdate 2.5g, titanium sulfate 1.5g, sodium silicate 0.1g, cerium nitrate 3g, benzotriazole 1g, phytic acid 0.1g, deionized water 81.8g.

[0041] 2. The preparation method is as follows: after mixing the above raw materials, use sulfuric acid with a mass fraction of 98% to adjust the pH value of the aqueous solution to 7.

[0042] Plate B was taken, and the tests (1)-(6) described in the above-mentioned Example 1 were carried out, and the test results are shown in Table 1 below.

Embodiment 3

[0044] Except following difference, other is with embodiment 1.

[0045] 1. Raw materials and contents for preparing composite passivation solution:

[0046] Cationic water-based polyurethane 12g, sodium molybdate 2g, titanium sulfate 1g, sodium silicate 1g, cerium nitrate 2g, benzotriazole 0.6g, phytic acid 1.2g, deionized water 80.2g.

[0047] 2. The preparation method is as follows: after mixing the above raw materials, adjust the pH value of the aqueous solution to 6 by using sulfuric acid with a mass fraction of 98%.

[0048] Plate C was taken, and the tests (1)-(6) described in the above-mentioned Example 1 were carried out, and the test results are shown in Table 1 below. Example 4

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Abstract

The invention belongs to the technical field of metal surface treatment and specifically relates to a compound passivating fluid for a mechanical zinc coating. The compound passivating fluid comprises a component A and a component B, wherein the component A is waterborne polyurethane, of which the weight percent is 8-18% in the compound passivating fluid; the component B is an inorganic passivator, of which the weight percent is 2.4-1.5% in the compound passivating fluid; and the balance is deionized water. The pH value of the compound passivating fluid is adjusted to 6-9 by using the sulfuric acid with the mass fraction of 98%. The compound passivating fluid has a better passivating function to a mechanical zinc coating workpiece; the environmental pollution caused by hexavalent chromium is avoided; a formed film is bright and transparent, is durable and excellent in flexibility, has a certain mechanical property, is excellent in water and chemical solvent resistance and is long in salt mist resisting time. The coating has the advantages of self-repairing function, high stability, low cost, simple preparation process and simple use method.

Description

technical field [0001] The invention belongs to the technical field of metal surface treatment, and in particular relates to a composite passivation solution for treating mechanical galvanized layers. Background technique [0002] The mechanical galvanized layer is mainly used to prevent atmospheric corrosion to protect steel parts. However, the mechanical galvanized layer is easily corroded in hot and humid air to form "white rust" and dark matter, which not only damages the appearance of the product, but also the corroded parts will continue to extend horizontally and vertically, thereby corroding the steel workpiece and forming rust. In order to improve the corrosion resistance of the mechanical galvanized layer, it is necessary to passivate the mechanically galvanized workpiece after plating. [0003] In the existing passivation process, chromate and inorganic passivation agents are generally used to passivate the mechanical galvanized layer. However, it is very diffic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C22/40C09D175/04C09D7/12
Inventor 丁金城卢杰姜玉旺
Owner SHANDONG UNIV OF TECH
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