Method for preparing chromium-free passivation solution, and method for passivating electrogalvanizing or zinc alloy layer by using same

A chromium-free passivation and electro-galvanizing technology, which is applied in the coating process of metal materials, etc., can solve the problems of short time, hexavalent chromium pollution of chromate passivation solution, etc.

Inactive Publication Date: 2010-06-16
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to solve the pollution problem of hexavalent chromium in the chromate passivation solution and the trivalent chromium passivation film, and the salt spray test after the existing passivation solution...

Method used

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  • Method for preparing chromium-free passivation solution, and method for passivating electrogalvanizing or zinc alloy layer by using same
  • Method for preparing chromium-free passivation solution, and method for passivating electrogalvanizing or zinc alloy layer by using same
  • Method for preparing chromium-free passivation solution, and method for passivating electrogalvanizing or zinc alloy layer by using same

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specific Embodiment approach 1

[0011] Specific embodiment one: the preparation method of chromium-free passivation solution in the present embodiment is as follows: one, the preparation of A concentrated solution: titanium salt, complexing agent, strong acid and oxidizing agent are dissolved in deionized water, obtain A concentrated solution, wherein The ratio of titanium salt to deionized water is 0.001-0.15g: 1mL, the ratio of complexing agent to deionized water is 0.005-0.3g: 1mL, the ratio of strong acid to deionized water is 0.001-0.05mL: 1mL, the ratio of oxidizing agent to The ratio of deionized water is 0.005 ~ 0.4g: 1mL; 2. Preparation of B concentrate: dissolve silicate, molybdate and phosphorus-containing substances in deionized water to obtain B concentrate, wherein silicate and deionized The ratio of ionized water is 0.005~0.25g: 1mL, the ratio of molybdate to deionized water is 0.005~0.25g: 1mL, the ratio of phosphorus-containing substances to deionized water is 0.005~0.1g: 1mL; The concentrat...

specific Embodiment approach 2

[0013] Embodiment 2: The difference between this embodiment and Embodiment 1 is that the titanium salt in step 1 is one of titanium trichloride and titanium sulfate or a mixture of both. Others are the same as in the first embodiment.

[0014] In this embodiment, when the titanium salt is a mixture of titanium trichloride and titanous sulfate, the ratio of titanium trichloride and titanous sulfate is arbitrary.

[0015] The stable time of the concentrated solution A and the concentrated solution B prepared in this embodiment is 45-60 days when stored separately, and the stable time of the chromium-free passivation solution prepared after mixing the concentrated solution A and B is 8-10 days. The A concentrated solution and the B concentrated solution in this embodiment are stored separately, and the A concentrated solution and the B concentrated solution are mixed before the passivation electroplated zinc or zinc alloy layer, and then prepared into a chromium-free passivation ...

specific Embodiment approach 3

[0016] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that the complexing agent described in step one is ethylenediaminetetraacetic acid, malic acid, glycine, sodium dihydrogen phosphate, α-hydroxyphenylacetic acid, fluorine One or a combination of sodium chloride and N-benzyloxycarbonyl amino acids. Others are the same as in the first or second embodiment.

[0017] In this embodiment, when the complexing agent is a composition, the ratio of each component is arbitrary.

[0018] The stable time of the concentrated solution A and the concentrated solution B prepared in this embodiment is 45-60 days when stored separately, and the stable time of the chromium-free passivation solution prepared after mixing the concentrated solution A and B is 8-10 days. The A concentrated solution and the B concentrated solution in this embodiment are stored separately, and the A concentrated solution and the B concentrated solution are mi...

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Abstract

The invention provides a method for preparing chromium-free passivation solution, and a method for passivating an electrogalvanizing or zinc alloy layer by using the same, and relates to a method for preparing the passivation solution and a using method thereof. The method solves the problems that passivation of hexavalent chromium and trivalent chromium generates pollution, and white rust tested in a salt spray test has short time after the electrogalvanizing or zinc alloy layer is passivated by the passivation solution. The method for preparing the chromium-free passivation solution comprises the following steps: 1, preparing concentrated solution A; 2, preparing concentrated solution B; and 3, regulating pH value after the concentrated solution A, the concentrated solution B and deionized water are mixed, and heating or cooling the mixture to 20 to 60 DEG C to obtain the chromium-free passivation solution. The method for passivating the electrogalvanizing or zinc alloy layer by using the chromium-free passivation solution comprises the following steps: 1, secondarily passivating the electrogalvanizing or zinc alloy layer; and 2, aging the electrogalvanizing or zinc alloy layer to complete passivation on the electrogalvanizing or zinc alloy layer. After the electrogalvanizing or zinc alloy layer is passivated by the chromium-free passivation solution, the electrogalvanizing or zinc alloy layer is subjected to neutral salt spray test, and the white rust does not appears on the surface of a passivated film after 84-120 hours of continuous spraying.

Description

technical field [0001] The invention relates to a preparation method and a use method of a passivation solution. Background technique [0002] Zinc and zinc alloys are easily corroded in hot and humid environments, and white spots and gray matter are formed on the surface. In order to improve the corrosion resistance and decorative properties of the galvanized layer, passivation treatment is required. The chromate passivation process makes the zinc coating passivate through chromate to form a mixed oxide film of chromium and zinc. The chromium ions in the film are mainly Cr 3+ and Cr 6+ exists in the form of Cr 3+ The oxide serves as the skeleton, although the Cr 6+ The oxide has strong oxidation and self-healing effect, but it is difficult to treat the waste liquid after chromate passivation, and the Cr contained in the waste liquid 6+ Ions are highly toxic and have great harm to the human body and the ecological environment. Trivalent chromium passivation is a low-to...

Claims

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Application Information

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IPC IPC(8): C23C22/42
Inventor 张锦秋安茂忠杨培霞李崇幸
Owner HARBIN INST OF TECH
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