A passivation solution for surface treatment of aluminum and aluminum alloys with manganate as main salt and its application

A technology of aluminum alloy surface and manganate, which is applied in the coating process of metal materials, etc., can solve the problems of environmental pollution, environmental secondary pollution, harmful to human health, etc., achieve low equipment requirements, improve corrosion resistance, and good durability The effect of corrosion performance

Inactive Publication Date: 2019-09-24
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is toxic hexavalent chromium in the chromate passivation process, which not only pollutes the environment but also is harmful to health, and the subsequent "three wastes" treatment will also cause secondary pollution to the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Embodiment 1: (do not add potassium fluoride and citric acid)

[0025] Example An industrial pure aluminum tube (1060) with a length of 6.00 cm and a diameter of Φ7.8×1.0 mm. Weigh 1.000g of potassium permanganate and 2.000g of disodium hydrogen phosphate, dissolve them in a 100mL volumetric flask, and adjust the pH to 9.5. Keep the temperature at 60°C, put the industrial pure aluminum tube into the solution for passivation for 10 minutes, and put it in an oven at 100°C for 1 hour to cure. Compared with the blank sample and the chromate passivation film, the manganate passivation film of the present invention has better corrosion resistance.

[0026] Using the electrochemical workstation to measure the Tafel polarization curves of different film layers, the data fitting result is: the self-corrosion current of the blank sample is 1.920×10 -4 A / cm 2 , the self-corrosion current of the chromate passivation film is 4.721×10 -5 A / cm 2 , the self-corrosion current of th...

Embodiment 2

[0027] Embodiment 2: (do not add citric acid)

[0028] Example An industrial pure aluminum tube (1060) with a length of 6.00 cm and a diameter of Φ7.8×1.0 mm. Weigh 1.000g of potassium permanganate, 2.000g of disodium hydrogen phosphate, and 0.100g of potassium fluoride, dissolve them in a 100mL volumetric flask, and adjust the pH to 9.0. Keep the temperature at 55°C, put the industrial pure aluminum tube into the solution for passivation for 10 minutes, and put it in an oven at 100°C for 1 hour to cure. Compared with blank sample and chromate passivation film, manganate passivation film has better corrosion resistance.

[0029] Using the electrochemical workstation to measure the Tafel polarization curves of different film layers, the data fitting result is: the self-corrosion current of the blank sample is 1.920×10 -4 A / cm 2 , the self-corrosion current of the chromate passivation film is 4.721×10 -5 A / cm 2 , the self-corrosion current of the manganate passivation film ...

Embodiment 3

[0031]Example An industrial pure aluminum tube (1060) with a length of 6.00 cm and a diameter of Φ7.8×1.0 mm. Weigh 1.000g of potassium permanganate, 2.000g of disodium hydrogen phosphate, 0.100g of potassium fluoride, and 0.200g of citric acid and dissolve them in a 100mL volumetric flask, and adjust the pH to 9.0. Keep the temperature at 55°C, put the industrial pure aluminum tube into the solution for passivation for 8 minutes, and put it in an oven at 100°C for 1 hour to cure. Compared with blank sample and chromate passivation film, manganate passivation film has better corrosion resistance.

[0032] Using the electrochemical workstation to measure the Tafel polarization curves of different film layers, the data fitting result is: the self-corrosion current of the blank sample is 1.920×10 -4 A / cm 2 , the self-corrosion current of the chromate passivation film is 4.721×10 -5 A / cm 2 , the self-corrosion current of the manganate passivation film is 8.658×10 -7 A / cm 2 ....

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Abstract

The invention discloses passivation liquid for surface treatment of aluminum and an aluminum alloy with manganate as main salt and application thereof. Manganate, a pH buffer agent and an additive are added in a proper amount of water for fully dissolving; the pH of solution is controlled by a pH adjusting agent; and the chemical plating is performed in a state of keeping constant temperature. An obtained passivation film is a tightly arranged golden yellow passivation film, and is low in corrosion current and better in corrosion resistance. The process is short in flow, simple in operation and high in production efficiency; and the generated passivation film is easy for observation and implement of industrial production.

Description

technical field [0001] The invention belongs to the technical field of anticorrosion and protection of metals, and in particular relates to a new passivation solution for surface treatment of aluminum and aluminum alloys using manganate as the main salt and a passivation process for improving the corrosion resistance of aluminum surfaces ability. Background technique [0002] Aluminum has the advantages of high specific strength, good thermal and electrical conductivity, beautiful color, non-magnetic, etc. It is a non-ferrous metal material with excellent comprehensive properties. At present, aluminum has been widely used in aerospace, construction, railway vehicles, mechanical equipment, food, clothing, housing and transportation. The use of aluminum in construction, automobiles, and packaging has become the three major uses of industrially developed countries in the world today. With the rapid development of the aluminum industry, there are higher requirements for the co...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): C23C22/66C23C22/73C23C22/78
Inventor满瑞林秘雪李波
OwnerCENT SOUTH UNIV