Organic precursor-based trivalent chromium black passivation solution and preparation method thereof

A technology of organic precursor and passivation solution, which is applied in the coating process of metal materials, etc., can solve problems such as environmental and human health hazards, environmental eutrophication, and difficulty in blackness adjustment, and achieve strong decoration and corrosion resistance Good, Simple Recipe for Effectiveness

Inactive Publication Date: 2010-09-15
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hexavalent chromium black passivation solution contains a large amount of hexavalent chromium compounds such as chromic anhydride, which is highly toxic and carcinogenic, and has serious hazards to the environment and human health
Although the films obtained by these processes are dense and bright, and have good corrosion resistance, the blackness of the film layer is insufficient, especially as the passivation solution ages, it becomes more and more difficult to adjust the blackness
Moreover, due to the use of phosphate ions in the passivation solution, it will cause eutrophication of the environment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1: With continuous stirring, 10 g of Cr 2 (SO 4 ) 3 ·6H 2 After O is dissolved in 500ml of pure water, add 11g of tartaric acid; after the two raw materials are completely dissolved, heat to 80 0 C to react, the reaction time is 2h; the solution is cooled to 30 after the reaction is completed 0 Add 10gKNO at C 3 , stir to dissolve; add 3g of acid medium black PV and stir to dissolve; add the remaining water to 1000ml and stir evenly to obtain.

[0027] The usage method of gained trivalent chromium black passivation solution is: prepare above-mentioned black passivation solution, use dilute HNO 3 Adjust the pH of the passivation solution to 2.2, and the passivation operating temperature to 40 0 C, the passivation time is 60S, and the passivation process is stirred with oil-free compressed air. After passivation is complete, 60 0 C hot water closed for 40s, at 75 0 C temperature drying. The passivation film of the product obtained by the treatment with ...

Embodiment 2

[0028] Example 2: Under continuous stirring, 23gCr(NO 3 ) 3 9H 2 After O is dissolved in 500ml of pure water, add 24g of citric acid; after the two raw materials are completely dissolved, heat to 90 0 C is reacted, and the reaction time is 3h; after the reaction is completed, the solution is cooled to 25 0 Add 11g NaNO at C 3 , stir to dissolve; add 4g of acid medium black T and stir to dissolve; add the remaining water to 1000ml and stir evenly to obtain.

[0029] The usage method of gained trivalent chromium black passivation solution is: prepare above-mentioned black passivation solution, use dilute HNO 3 Adjust the pH of the passivation solution to 2.3, and the passivation operating temperature to 35 0 C, the passivation time is 50S, and the passivation process is stirred with oil-free compressed air. After passivation is complete, the 55 0 C hot water closed for 35s, at 80 0 C temperature drying. The passivation film of the product obtained by the treatment wit...

Embodiment 3

[0030] Example 3: With continuous stirring, 5 g of Cr 2 (SO 4 ) 3 ·6H 2 O and 10gCr(NO 3 ) 3 9H 2 After O is dissolved in 500ml of pure water, add 12g of citric acid and 5g of tartaric acid; after the two raw materials are completely dissolved, heat to 85 0 C to react, the reaction time is 2h; the solution is cooled to 30 after the reaction is completed 0 Add 11g NaNO at C 3 , stir to dissolve; add 2g of acidic medium black PV and 2g of acidic medium black T, stir and dissolve; add the remaining water to 1000ml and stir evenly to get ready. income

[0031] The usage method of gained trivalent chromium black passivation solution is: prepare above-mentioned black passivation solution, use dilute HNO 3 Adjust the pH of the passivation solution to 2.2, and the passivation operating temperature to be 30 0 C, the passivation time is 60S, and the passivation process is stirred with oil-free compressed air. After passivation is complete, 60 0 C hot water closed for 30s, ...

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PUM

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Abstract

The invention relates to organic precursor-based trivalent chromium black passivation solution and a preparation method thereof, and belongs to the technical field of metal surface treatment. The passivation solution comprises 0.1 to 10g/L of Cr3+, 0.5 to 30g/L of organic carboxylic acid, 0.1 to 10g/L of acid mordant dye, 1 to 20g/L of NO3- and the balance of pure water. The preparation method for the passivation solution comprises the following steps of: dissolving the Cr3+ compound in the pure water; adding the organic carboxylic acid into the mixture; after the organic carboxylic acid is completely dissolved, heating the obtained product to the temperature of between 70 and 90 DEG C to perform a reaction for 1 to 2 hours; after the reaction is completed, cooling the solution to the temperature of between 20 and 30 DEG C; adding the NO3- into the solution; stirring and dissolving the mixture; adding the acid mordant dye into the obtained product to stir and dissolve the mixture; and supplementing the balance of water to a regulated volume to uniformly stir the mixture. The organic precursor-based trivalent chromium black passivation solution and the preparation method thereof have the advantages of simple passivation solution formula, simple and convenient preparation and passivation operation process of the passivation solution, low passivation cost and high added value of the product.

Description

technical field [0001] The invention relates to metal surface treatment technology, in particular to a trivalent chromium black passivation solution based on an organic precursor and a preparation method thereof. Background technique [0002] The black passivation film of the galvanized layer is black and shiny in appearance, uniform in color, elegant and dignified. In recent years, the black passivation process has been increasingly favored by people, and its application range is becoming wider and wider. At present, galvanized black passivation mainly uses hexavalent chromium passivation process. Hexavalent chromium black passivation solution contains a large amount of hexavalent chromium compounds such as chromic anhydride, which is highly toxic and carcinogenic, and has serious hazards to the environment and human health. With the improvement of people's awareness of environmental protection, its use is increasingly restricted. The contradiction between the market dem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/53
CPCC23C2222/10C23C22/53
Inventor 沈刚
Owner HUNAN UNIV
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