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Environmentally friendly chromium-free passivation solution for aluminum and aluminum alloy surface and application thereof

A chromium-free passivation and environment-friendly technology, applied in the coating process of metal materials, etc., can solve the problems of pollution, environmental secondary pollution, etc., and achieve the effects of saving money, short processing time, and improving the production environment

Inactive Publication Date: 2012-01-04
ZHEJIANG IND & TRADE VACATIONAL COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chromate passivation treatment can significantly improve the corrosion resistance of aluminum and its alloy surface. At the same time, the passivation film has good adhesion to the coating and is low in cost, so it has been widely used. However, chromate passivation treatment The solution contains hexavalent chromium, which is extremely harmful to the human body and the environment. Not only will pollution occur during the treatment process, but the hexavalent chromium in the passivation film will also cause secondary pollution to the environment when the treated product is used or discarded in the future.
[0004] As people's awareness of environmental protection increases, the application of hexavalent chromium has been gradually restricted

Method used

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  • Environmentally friendly chromium-free passivation solution for aluminum and aluminum alloy surface and application thereof
  • Environmentally friendly chromium-free passivation solution for aluminum and aluminum alloy surface and application thereof
  • Environmentally friendly chromium-free passivation solution for aluminum and aluminum alloy surface and application thereof

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Effect test

Embodiment 1

[0034] The present invention adopts the following steps successively to obtain a passivation film resistant to 5% sodium chloride neutral salt spray up to 200 hours on aluminum and its alloy workpieces:

[0035] (a) Degreasing, descaling, activation and cleaning of workpieces made of aluminum and its alloys;

[0036] (b) Prepared to contain ammonium molybdate 2-50 g / L, sodium fluoroborate 1-20 g / L, sodium nitrite 1-15 g / L, glacial acetic acid (99.5%) 0.5-10 mL / L, boric acid 0.5-10 g / L passivation solution, when the temperature of the solution is normal temperature, immerse the workpiece with clean surface treatment in the passivation solution for 10-30 minutes;

[0037] (c) After passivation is completed, take it out for cleaning and dry or dry it.

Embodiment 2

[0039] The present invention adopts the following steps successively to obtain a passivation film resistant to 5% sodium chloride neutral salt spray up to 200 hours on aluminum and its alloy workpieces:

[0040] (a) Degreasing, descaling, activation and cleaning of workpieces made of aluminum and its alloys;

[0041] (b) Passivation solution configuration, configured to contain ammonium molybdate 2 g / L, sodium fluoroborate 1 g / L, sodium nitrite 1 g / L, glacial acetic acid (99.5%) 0.5 mL / L, boric acid 0.5 g / L 1 liter of passivation solution, when the temperature of the solution is normal temperature, immerse the workpiece with clean surface treatment in the passivation solution for passivation, and the time is 10 minutes;

[0042] (c) After passivation is completed, take it out for cleaning and dry or dry it.

Embodiment 3

[0044] The present invention adopts the following steps successively to obtain a passivation film resistant to 5% sodium chloride neutral salt spray up to 200 hours on aluminum and its alloy workpieces:

[0045] (a) Degreasing, descaling, activation and cleaning of workpieces made of aluminum and its alloys;

[0046] (b) Prepare a passivation solution containing 50 g / L of ammonium molybdate, 20 g / L of sodium fluoroborate, 15 g / L of sodium nitrite, 10 mL / L of glacial acetic acid (99.5%), and 10 g / L of boric acid , when the temperature of the chemical solution is normal temperature, immerse the workpiece with clean surface treatment in the passivation solution for passivation, and the time is 30 minutes;

[0047] (c) After passivation is completed, take it out for cleaning and dry or dry it.

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Abstract

The invention discloses an environmentally friendly chromium-free passivation solution for aluminum and aluminum alloy surface and application thereof. The passivation solution consists of molybdate, fluoroborate, nitrate, boric acid and an acidic catalyst, wherein the molybdate is one or a complex of sodium molybdate and potassium molybdate; the fluoroborate is one or a complex of sodium fluoroborate and potassium fluoroborate; the nitrate is one or a complex of sodium nitrate, potassium nitrate, copper nitrate and calcium nitrate; and the acidic catalyst is one or a complex of nitric acid, sulfuric acid, phosphoric acid and acetic acid. The content of the molybdate is 3-50 g / L, the content of the fluoroborate is 1-20 g / L, the content of the nitrate is 1-15 g / L and the content of the boric acid is 0.1-10 g / L; and the acidic catalyst is used to adjust the pH value to 2-6 and the temperature condition is the room temperature. The aluminum and aluminum alloy workpieces are degreased, descaled, activated and cleaned and then placed in the passivation solution to passivate, and the corrosion resistance of the aluminum alloy can be increased.

Description

technical field [0001] The invention belongs to the field of metal surface treatment, and specifically refers to an environment-friendly chromium-free passivation solution for the surface of aluminum and its alloys and its application. Background technique [0002] Aluminum is one of the most abundant metal elements in nature. Because aluminum and its alloys have the advantages of small specific gravity, good thermal and electrical conductivity, strong light reflection, easy forming and processing, excellent physical and chemical properties, and low price, they are currently widely used. Used in electronic communication, home appliances, construction, automobile, plumbing and other fields. However, aluminum alloys are prone to damage in the form of pitting corrosion, crevice corrosion, stress corrosion and corrosion fatigue when used in humid, alkaline media such as industrial gases and fuel gases, and salt water. [0003] In order to prevent aluminum and its alloys from be...

Claims

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Application Information

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IPC IPC(8): C23C22/44
Inventor 徐临超华学兵牛丽缓林继兴李勇栾成洋
Owner ZHEJIANG IND & TRADE VACATIONAL COLLEGE
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