Transformation liquid for preparation of corrosion-resistant oxidation film on aluminium alloy surface and method of use thereof

A technology of aluminum alloy surface and corrosion resistance, applied in the direction of metal material coating process, etc., can solve the problem of low film formation efficiency, and achieve the effect of less environmental pollution, uniform film layer and fast formation speed

Inactive Publication Date: 2008-03-12
陈东初 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a low-temperature, high-efficiency, low-temperature, high-efficiency solution that not only solves the problem of low film-forming efficiency of the current chromium-substituting treatment soluti

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] After the solution of the present invention is prepared, it needs to be stirred rapidly under air to make the solution fully react. During chemical conversion treatment, the micro-cathode and micro-anode on the surface of aluminum alloy undergo electrochemical reactions (there are micro-anode and micro-cathode on the surface of aluminum alloy in the electrolyte, anode: aluminum-magnesium metal phase with relatively negative potential, cathode: possibly near aluminum alloy Elements or intermetallic compounds with relatively positive potential. The electrochemical reaction of the micro-cathode and micro-anode on the surface of the aluminum alloy leads to a high pH area on the surface of the aluminum alloy sample, which deposits hydroxide precipitation.

[0023] The reaction of the conversion coating on the aluminum alloy surface can be expressed as follows:

[0024] Micro-anode reaction on aluminum alloy surface:

[0025] Al-3e-→Al 3+ (1)

[0026] Cathodic reaction:

[002...

Embodiment 2

[0057] The difference between this embodiment and the above-mentioned embodiment is that the LY12 aluminum alloy is subjected to the same pretreatment as described in Embodiment 1, and then placed in a chemical composite conversion solution for treatment. Ce salt 12g·L -1 , Potassium Permanganate 1.5g·L -1 , Potassium perchlorate 0.3g·L -1 , Strontium chloride 1.0g·L -1 , Nitric acid 15mL·L -1 , Sodium Nitrate 10g·L -1 , Phytic acid 0.2g·L -1 , Sodium dodecylbenzene sulfonate wetting agent 0.5g·L -1 , The temperature is room temperature, and the treatment time is 3 minutes; after the reaction is completed, rinse with deionized water, air dry naturally, and store dry. The surface of the treated LY12 aluminum alloy forms a golden yellow conversion coating with ideal corrosion resistance, which has passed the 168-hour neutral salt spray test (ASTM B117) and reached level 8.

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Abstract

The invention discloses a transforming solution for preparing anti-corrosion compound oxidation film on an aluminum alloy surface and a using method for the oxidation film. The invention is characterized in that, the transforming solution is a film-forming promoter containing rare-earth salt (nitrate or sulfate and compound salt of cerium, praseodymium, and neodymium), such compound oxidant as radical of permanganate, nitrate and perchlorate, etc., film-forming promoter of vanadium salt and strontium salt, etc.; the transforming solution contains no sexavalent chromium, is environmental friendly; the reaction speed is improved by the compound oxidant and the film-forming promoter, no heating is needed for the chemical transforming, the treating time is 1-5 min. The invention can rapidly prepare under room temperature compound oxidation film comprising compound rare-earth oxide, alumina and manganese oxide with good resistance to corrosion on aluminum alloy surface. The treating solution from the invention is of rapid film-forming speed, simple process, even film layer, high resistance to corrosion, and low environmental pollution, etc.

Description

Technical field [0001] The invention relates to the field of surface treatment of aluminum alloys, in particular to the use of an environment-friendly non-chromium rare earth conversion treatment solution to rapidly prepare chemical conversion coatings based on rare earth elements and manganese composite oxides with good corrosion resistance on the aluminum alloy surface at room temperature . Background technique [0002] Because of its low density, high specific strength, easy processing and forming, castable, strengthenable, strong thermal conductivity, no low temperature brittleness, non-magnetic, strong reflection of light and heat, and resistance to nuclear radiation, aluminum alloy is used in Automobiles, aerospace, architectural decoration, home appliances, instrumentation, computers, mobile phones, daily hardware and many other fields have become the second largest metal structure material after steel in consumption. Due to the high chemical activity of aluminum and its a...

Claims

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Application Information

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IPC IPC(8): C23C22/06C23C22/40
Inventor 陈东初李文芳黄铭深
Owner 陈东初
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