Composition for chemical conversion treatment and part having chemical conversion film formed from the composition

A technology for chemical conversion treatment and chemical conversion film, applied in the field of compositions for chemical conversion treatment

Active Publication Date: 2011-12-28
YUKEN KOGYO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, such films become the object of the above directive restrictions
[0004] It can be understood that chromate formed from the chemical conversion treatment solution containing trivalent chromium as described above is very common, but it is indisputable that a very small amount of hexavalent chromium can be detected in the chemical conversion coating obtained by using the chemical conversion treatment solution. fact

Method used

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  • Composition for chemical conversion treatment and part having chemical conversion film formed from the composition
  • Composition for chemical conversion treatment and part having chemical conversion film formed from the composition
  • Composition for chemical conversion treatment and part having chemical conversion film formed from the composition

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0107] The chemical conversion treatment was performed using a chemical conversion treatment liquid obtained by changing the addition amount of the water-soluble cobalt compound and the addition amount of the pyrogallol compound to the known chemical conversion treatment liquid containing trivalent chromium, and the effect was evaluated.

[0108] (1) Preparation of test parts

[0109] First, using nitric acid and sodium hydroxide, chromium chloride as a water-soluble trivalent chromium compound containing 2.6 g / L in terms of chromium content, and cobalt nitrate and cobalt nitrate as a water-soluble cobalt compound shown in Table 1 were prepared. The chemical conversion treatment solution of the dissolution inhibitor is adjusted to a pH of 2.0. It should be noted that the cobalt conversion content in Table 1 refers to the cobalt conversion content of the added cobalt nitrate, but since all the added cobalt nitrate is dissolved in the chemical conversion treatment liquid, it is ...

Embodiment 2

[0145] Using a known chemical conversion treatment liquid containing trivalent chromium, the addition amount of the water-soluble cobalt compound was changed within the range of 1.0 to 3.0 g / L, and the addition amount of the pyrogallol compound and the organic phosphonic acid compound The changed chemical conversion treatment liquid is subjected to chemical conversion treatment, and its effect is evaluated.

[0146] (1) Preparation of test parts

[0147] First, using nitric acid and sodium hydroxide, chromium chloride as a water-soluble trivalent chromium compound containing 2.0 g / L in terms of chromium and cobalt nitrate as a water-soluble cobalt compound shown in Table 3 were prepared, The chemical conversion treatment solution of pyrogallol as an elution inhibitor and 1-hydroxyethylidene-1,1-diphosphonic acid as an organic phosphonic acid compound was adjusted to have a pH of 2.0. It should be noted that the cobalt conversion content in Table 3 refers to the cobalt convers...

Embodiment 3

[0173]Using a known chemical conversion treatment liquid containing trivalent chromium, the addition amount of the water-soluble cobalt compound is changed in the range of 0.10 to 0.50 g / L, and the addition amount of the pyrogallol compound and the organic phosphonic acid compound is changed. The chemical conversion treatment liquid, carry out chemical conversion treatment, and evaluate its effect.

[0174] (1) Preparation of test parts

[0175] First, using nitric acid and sodium hydroxide, chromium chloride as a water-soluble trivalent chromium compound containing 2.0 g / L in terms of chromium and cobalt nitrate as a water-soluble cobalt compound shown in Table 4 were prepared, The chemical conversion treatment solution of pyrogallol as an elution inhibitor and 1-hydroxyethylidene-1,1-diphosphonic acid as an organic phosphonic acid compound was adjusted to have a pH of 2.0. It should be noted that the cobalt conversion content in Table 4 refers to the cobalt conversion conte...

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Abstract

Disclosed is a chemical conversion coating solution which enables the formation of a chemical conversion coating film that has excellent corrosion resistance and good appearance and is reduced in the hexavalent chromium release amount. The chemical conversion coating solution comprises an acidic composition which comprises a water-soluble cobalt-containing substance in an amount of 0.1 to 3.0 g / Lin terms of a cobalt content, a pyrogallol compound in an amount of 0.05 to 3.0 g / L in terms of a pyrogallol content, and a water-soluble trivalent-chromium-containing substance in an amount of 1.5 g / L or more in terms of a chromium content all relative to the total amount of the composition, wherein the ratio of the content of the pyrogallol compound in terms of a pyrogallol content to the content of the water-soluble cobalt-containing substance in terms of the cobalt content is 0.015 to 10. When the composition is brought in contact with a metal surface of a member to form a chemical conversion coating film on the metal surface and the chemical conversion coating film is exposed to an environment of 80 DEG C and 100% RH for 72 hours, the hexavalent chromium concentration in the chemicalconversion coating film is less than 0.050 [mu]g / cm2 as determined by an analysis method in accordance with EN15205.

Description

technical field [0001] The present invention relates to a composition for chemical conversion treatment capable of forming a chemical conversion film capable of inhibiting 6 The dissolution of chromium. Specifically, it relates to a composition for chemical conversion treatment, a concentrated composition for preparing the composition, and a method for producing a part having a chemical conversion coating formed from the composition. Background technique [0002] In recent years, according to directives that consider the environment such as the RoHS directive ("Restriction on the use of certain hazardous components in electrical and electronic cadmium, hexavalent chromium, etc.). [0003] Affected by this trend, a chromate film that is effective as a chemical conversion film for corrosion protection of parts having a metal surface such as galvanized parts is not a composition for chemical conversion treatment using a chromate containing hexavalent chromium (Hereinafter, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/07C23C22/08C23C22/34
CPCC23C2222/10C23C22/53
Inventor 野岛成彦石川周作石川智子
Owner YUKEN KOGYO
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