Process for preparing magnesium alloy chemical conversion coating

The invention relates to a technology for a chemical conversion film and a preparation process, which is applied in the field of chromate-free anti-corrosion treatment technology, and can solve the problem that the treatment liquid contains toxic chemical substances, so as to achieve the effects of good corrosion resistance, simple process and operation method, and harm elimination.

Active Publication Date: 2009-08-26
靖江市华信科技创业园有限公司
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  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantage of existing conversion coatings is that the treatment fluid contains toxic chemicals
Traditional conversion coating treatment fluids are based on various compounds of chromium, which is highly carcinogenic

Method used

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Embodiment Construction

[0039] The steps of the magnesium or magnesium alloy chemical conversion film preparation process of the present invention include: degreasing, water washing, pickling, water washing, activation, water washing, chemical formation, sealing and drying, and the specific steps are as follows:

[0040] a, degreasing: be 1% by weight percentage, the sodium hydroxide that concentration is 15g / L, 3% by weight percentage, the sodium phosphate that concentration is 40g / L, 1.5% by weight percentage, the sodium carbonate that concentration is 15g / L and sodium silicate with a weight percentage of 1.5% and a concentration of 15 g / L to form a mixed solution, and degrease the magnesium or magnesium alloy at a temperature of 65° C. for 3 minutes. After degreasing, it can be washed with deionized water several times to clean the degreasing liquid remaining on the magnesium or magnesium alloy workpiece.

[0041] b. Pickling: use 2% by weight, phosphoric acid with a concentration of 20ml / L and 1%...

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Abstract

A preparation process of a magnesium alloy chemical conversion coating, the process comprises the following steps: a, using a sodium hydroxide solution or a mixed solution of one or more of sodium phosphate, sodium carbonate and sodium silicate solution containing sodium hydroxide on the Magnesium or magnesium alloy is degreased; b. The degreased magnesium or magnesium alloy is pickled with a mixed solution of phosphoric acid and sodium phosphate; c. The pickled magnesium is treated with a mixed solution of hydrofluoric acid and sodium phosphate. or magnesium alloy for activation treatment; d, use a mixed solution of calcium nitrate hexahydrate, sodium nitrite, sodium iodide, hydrogen peroxide to carry out chemical conversion treatment on activated magnesium or magnesium alloy; e, use deionized water to chemical conversion treatment Magnesium or magnesium alloy for sealing. Because the present invention does not contain chromium compounds in the treatment liquid, it eliminates possible harm to the environment caused by toxic substances. The invention also has the characteristics of simple process and operation method, low cost, suitable for batch production and the like.

Description

technical field [0001] The invention relates to a metal surface treatment process, in particular to a chromate-free anti-corrosion treatment process for magnesium and magnesium alloys. Background technique [0002] Magnesium alloy is currently the lightest metal engineering material. Its density is 1.74g / cm3, which is only 2 / 3 of aluminum and 1 / 4 of iron. At the same time, it has the characteristics of high specific strength and good processing performance. , aerospace, electronic IT, and military products have broad application prospects, and are known as "green engineering materials in the 21st century". However, magnesium has active chemical properties, low stability, negative standard electrode potential (-2.36eV), and extremely poor corrosion resistance. It will also oxidize in the air even at room temperature, and the surface oxide film is loose and alkaline. Its pH value is about 10.5, which is not conducive to painting. Therefore, poor corrosion resistance has beco...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C22/05C23C22/78
Inventor 肖美群
Owner 靖江市华信科技创业园有限公司
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