Aluminum alloy surface rare earth chemical conversion treatment method

A technology for chemical conversion treatment, aluminum alloy surface, applied in chemical instruments and methods, cleaning methods and utensils, cleaning methods using liquids, etc. Excellent protective performance, fast film formation and simple operation

Inactive Publication Date: 2008-09-10
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with the traditional chromate treatment process, the long-term stability of the treatment solution and the treatment cost need to be further improved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Example 1: Rare earth conversion treatment on the surface of 6061 aluminum alloy profile (thickness 1.6mm)

[0031] The rare earth chemical conversion treatment method on the surface of aluminum alloy comprises the following steps:

[0032] (1) Pretreatment: (a) Cut 5X5cm from 6061 large-size aluminum alloy profile (thickness 1.6mm) 2 6 pieces of samples were drilled, and polished with SiC water sandpaper until the surface roughness was below 10 microns, and the surface dirt was cleaned and dried with tap water, and aluminum wires were connected at the punched places; (b) the weak corrosion alkaline Put the solution into a heatable ultrasonic cleaning machine, heat it to 70°C, put it into an aluminum alloy test piece, ultrasonically clean it for 10 minutes, and then rinse it with deionized water; the weak corrosion alkaline solution is composed of anhydrous sodium carbonate, tripolyphosphoric acid Sodium and sodium silicate are configured with deionized water, and the ...

Embodiment 2

[0036] Example 2: Rare earth conversion treatment on the surface of 6061 aluminum alloy profile (thickness 1.6mm)

[0037] The rare earth chemical conversion treatment method on the surface of aluminum alloy comprises the following steps:

[0038] (1) Pretreatment: (a) perform mechanical polishing on the surface of the aluminum alloy, and control the surface roughness to be below 2 microns; (b) use a weakly corrosive alkaline solution for ultrasonic cleaning at 60°C for 10 minutes, and the weakly corrosive alkaline solution is prepared by Composed of anhydrous sodium carbonate, sodium tripolyphosphate, sodium silicate and deionized water, every liter of weakly corrosive alkaline solution contains 30g of anhydrous sodium carbonate, 50g of sodium tripolyphosphate and 10g of sodium silicate; (c) Rinse with deionized water; dip in alkaline solution at 60°C for 1 minute, the alkaline solution is composed of sodium hydroxide, sodium tripolyphosphate, anhydrous sodium carbonate and w...

Embodiment 3

[0042] Example 3: Rare earth conversion treatment on the surface of 6061 aluminum alloy profiles (thickness 1.6mm)

[0043] The rare earth chemical conversion treatment method on the surface of aluminum alloy comprises the following steps:

[0044] (1) Pretreatment: (1) Pretreatment: (a) perform mechanical polishing on the surface of the aluminum alloy, and control the surface roughness to be less than 1 micron; (b) use a weakly corrosive alkaline solution for ultrasonic cleaning at 80°C for 5 minutes, The weakly corrosive alkaline solution is composed of anhydrous sodium carbonate, sodium tripolyphosphate, sodium silicate and deionized water. Each liter of weakly corrosive alkaline solution contains 50g of anhydrous sodium carbonate, 30g of sodium tripolyphosphate and 25g of silicon (c) rinsing with deionized water; dipping in an alkaline solution at 80°C for 1 minute, based on the weight-to-volume ratio of the components, the alkaline solution is composed of sodium hydroxide...

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Abstract

The invention discloses a method for treating the rare earth chemical conversion on the surface of aluminium alloy. The method comprises a pretreatment procedure on the surface of the aluminium alloy, the preparation of rare earth chemical conversion treating liquid and the treatment of rare earth chemical conversion. The rare earth chemical conversion treating liquid consists of 10 to 30g/L cerium salt, 1 to 5g/L oxidant solution, 0 to 5x10<-2> mol/L film forming accelerant and 1 to 3g/L film forming surface morphology truing agent; the PH value of the treating liquid is 1 to 3; the cerium salt is selected form one or two of hydrous cerium chloride and hydrous cerous nitrate; the film forming accelerant is one or a plurality of transitional metal free ions; the film forming process is completed in 5 to 15 minutes. The method for treating a coating by conversion has high combining intensity with a substrate, good protective performance and simple structure; the coating contains no hexavalent chrome or trivalent chromium which is harmful to the environment and human body.

Description

technical field [0001] The invention relates to a chemical conversion treatment method on the surface of aluminum alloy, in particular to a rare earth chemical conversion treatment method on the surface of aluminum alloy, which can obtain a uniform thickness and dense golden-yellow rare earth oxide coating on the surface of aluminum alloy to replace traditional chromic acid Salt conversion treatment. Background technique [0002] Aluminum alloy has become the second largest metal material in use after steel. Under atmospheric conditions, aluminum alloys can form a very thin oxide film on the surface to avoid corrosion. However, this spontaneous oxide film is easily damaged, especially in an environment containing Cl, and various damages such as pitting corrosion, crevice corrosion, and stress corrosion are extremely prone to occur. In order to overcome the shortcomings of aluminum alloy surface properties, expand its application range, and prolong its service life, aluminu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/56C23C22/78C23G1/22B08B3/12
Inventor 彭继华李文芳
Owner SOUTH CHINA UNIV OF TECH
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