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Preparation for aluminum or aluminum alloy trivalent chromium chemical conversion film

A technology of chemical conversion coating and trivalent chromium, applied in chemical instruments and methods, cleaning methods using liquids, cleaning methods and utensils, etc., can solve problems such as toxicity, achieve low cost, simple and easy process, and fast film formation time short effect

Inactive Publication Date: 2008-10-01
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to provide a method for preparing aluminum or aluminum alloy trivalent chromium chemical conversion film, which uses low-toxic trivalent chromium compound as raw material to carry out chemical conversion film treatment on the surface of aluminum and aluminum alloy, solving the problem of the original Hexavalent chromium as the main component of aluminum and aluminum alloy surface conversion coating process has the disadvantage of high toxicity, so as to meet the requirements of environmental protection, while not changing the quality of the chromium conversion coating

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  • Preparation for aluminum or aluminum alloy trivalent chromium chemical conversion film

Examples

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Embodiment 1

[0014] Example 1: Trivalent chromium chromization of 6061 aluminum alloy

[0015] Build a 500L degreasing bath: Clean the container thoroughly before building the bath. For new containers or new production lines, first wash with 20% sulfuric acid solution, then wash with water twice, each time with 100L of water, and then add 10kg of Henkel’s Degreaser Ridoline212, and then diluted to 500L with deionized water, the pH is controlled at 8.

[0016] Build an activation bath: Clean the container thoroughly before building the bath. For a new container or a new production line, first clean it with 15% sulfuric acid solution, then clean it with water, add 75kg of sodium hydroxide, and then dissolve it with deionized water. Then dilute to 500L with deionized water, mix well, and keep the temperature at 25°C.

[0017] Build a 500L chromium bath: Clean the container thoroughly before building the bath. For new containers or new production lines, first clean them with 15% sulfuric acid...

Embodiment 2

[0019] Embodiment 2: Trivalent chromium chromization of 6063 aluminum alloy

[0020] Build a 400L degreasing bath: clean the container thoroughly. For new containers or new production lines, first wash with 40L of 20% sulfuric acid solution, then wash with water twice, each time with 80L of water, and then add 8KG of Henkel’s degreasing powder Ridoline212, and then diluted to 400L with deionized water, pH control at 7.8.

[0021] Build a 400L activation bath: Clean the container thoroughly before building the bath. For a new container or new production line, first clean it with 15% sulfuric acid solution, then clean it with water, add 50kg of sodium hydroxide, and then dissolve it with deionized water Then dilute to 400L with deionized water, mix evenly, and keep the temperature at 30°C.

[0022] Build a 400L chromium bath: clean the container thoroughly before building the bath. For new containers or new production lines, first clean them with 15% sulfuric acid solution, the...

Embodiment 3

[0024] Embodiment 3: Trivalent chromium chromization of aluminum alloy die castings

[0025] Build a 300L degreasing bath: Clean the container thoroughly. For new containers or new production lines, first wash with 50L of 20% sulfuric acid solution, and then wash with water twice, each time with 60L of clean water, then add 6kg of degreasing powder Ridoline212, and then Dilute to 300L with deionized water and keep the pH at 7.

[0026] Build a 300L activation bath: Clean the container thoroughly before building the bath. For new containers or new production lines, first clean them with 15% sulfuric acid solution, then clean them with water, add 25kg of sodium hydroxide, and then use deionized water Dissolve and dilute to 300L with deionized water, mix well, and keep the reaction temperature at 5°C.

[0027] Build a 300L chromium bath: clean the container thoroughly before building the bath. For new containers or new production lines, first clean them with 15% sulfuric acid so...

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Abstract

The invention discloses a method of preparing aluminum or aluminum alloy trivalent chromium chemical conversion film, comprising: aluminum or aluminum alloy work pieces are activated for 1 to 2 minutes in sodium hydroxide solution with a concentration of 50g / L to 100g / L and activation reaction temperature is 5 deg C to 30 deg C; using deionized water to wash the work pieces; putting the washed work pieces into mixed aqueous solution of soluble chromic salt and phosphoric acid to make a chromaking for 6 to 10 minutes, wherein, chromium ion has a concentration of 1g / L to 20g / L, and the phosphoric acid has a concentration of 1g / L to 25g / L; using dilute sodium hydroxide or dilute sulfuric acid to adjust reaction system PH value to 1.6 to 4.0 and the chromaking temperature to 10 deg C to 60 deg C. The invention solves a shortcoming that in existing technology hexavalent chromium has great toxicity. Technological process and products of the invention reach environmental requirements. The produced trivalent chromium chemical conversion film has the same quality with hexavalent chromium chemical conversion.

Description

technical field [0001] The invention relates to aluminum alloy surface treatment, in particular to a method for preparing a chemical conversion film on the surface of aluminum or aluminum alloy. Background technique [0002] The natural oxide film on the surface of aluminum and aluminum alloy is about 5nm. Due to its thin thickness, it is easy to wear and scratch, and its corrosion resistance is poor. layer of aluminum rust. In order to improve the corrosion resistance of the oxide film on the surface of aluminum and aluminum alloy, it is necessary to manually process the surface of aluminum and aluminum alloy to increase the thickness of the oxide film. At present, the most widely used ones are mainly chemical conversion coating and anodic oxidation treatment. Compared with anodic oxidation, chemical conversion coating has the advantages of simple operation, low cost, less energy consumption, short film forming time, low requirements on substrate material, and less influe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/04B08B3/04
CPCC23C2222/10
Inventor 余会成陈白珍徐徽杨喜云石西昌
Owner CENT SOUTH UNIV
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