CN102199775A - Pickling solution and method for treating magnesium alloy - Google Patents

Abstract

A magnesium alloy pickling solution for pickling and activation treatment of magnesium alloys, using water as a solvent, including the following components calculated by concentration: 2-5g/L sulfuric acid, 6-10g/L phosphoric acid and 3-5g /L of fluoride. The invention also provides a magnesium alloy pickling method. The magnesium alloy pickling solution and method of the present invention uses a mixture of inorganic strong acid and fluoride, does not contain chromium, has no pollution to the environment, and the solution reacts quickly, and can quickly remove oxides, release agents and oxides on the surface of magnesium alloys. Silicon impurities, and make the surface of the magnesium alloy have good adhesion.

Description

Magnesium alloy pickling solution and method

【Technical field】

The invention relates to a pickling solution and method, in particular to a magnesium alloy pickling solution and method for pickling activation treatment of magnesium alloys.

【Background technique】

Magnesium alloy is lighter than engineering plastics, and with the gradual reduction in weight and thickness of consumer electronic products, it has gradually become the main basic material in consumer electronic products such as notebook computers, mobile phones, PDAs and projectors, and has become a material for electronic information products. As a rising star, the scope of application of magnesium alloys has rapidly expanded. In industrial production, the surface treatment of magnesium alloys is becoming more and more important. The surface treatment is mainly to improve the appearance of the product and improve the wear resistance and corrosion resistance.

Before the magnesium alloy chemical conversion treatment, the magnesium alloy material must be pickled and activated to remove oxides, corrosion products and other pollutants on its surface, so as to improve its surface quality. At present, many magnesium alloy pickling processes still use solutions containing chromium compounds. However, because hexavalent chromium is discharged through wastewater, it will cause water and soil pollution, and harm animals and plants, so it does not meet the requirements of environmental protection. Countries around the world have successively banned the use of chromium-containing compounds.

【Content of invention】

In view of this, the object of the present invention is to provide a magnesium alloy pickling solution and method that does not contain chromium compounds and is beneficial to environmental protection.

In order to achieve the above object, a kind of magnesium alloy pickling solution for magnesium alloy pickling activation treatment provided by the invention, with water as solvent, includes the following components calculated by concentration:

(a) sulfuric acid 2-5g/L;

(b) phosphoric acid 6-10g/L;

(c) Fluoride 3-5g/L.

In order to achieve the above object, the present invention also provides a magnesium alloy pickling method for carrying out pickling and activation treatment of a magnesium alloy material, comprising the following steps:

Degreasing the magnesium alloy material to remove grease on the surface of the magnesium alloy;

The degreased magnesium alloy material is placed in a magnesium alloy pickling solution for pickling activation treatment. The magnesium alloy pickling solution uses water as a solvent and includes the following components calculated by concentration: 2-5g/L sulfuric acid, 6-10g/L phosphoric acid and 3-5g/L fluoride, the treatment temperature is at room temperature, and the treatment time is between 60-120 seconds; and the magnesium alloy material is ultrasonically washed with pure water.

The magnesium alloy pickling solution and method of the present invention uses a mixture of inorganic strong acid and fluoride, does not contain chromium, has no pollution to the environment, and the solution reacts quickly, and can quickly remove oxides, release agents and oxides on the surface of magnesium alloys. Silicon impurities, and the surface of the magnesium alloy has good adhesion.

【Description of drawings】

FIG. 1 is a flow chart of a preferred embodiment of the magnesium alloy pickling method of the present invention.

【Detailed ways】

Below in conjunction with specific embodiment the present invention is described in further detail:

The magnesium alloy pickling solution of the present invention uses water as a solvent, and comprises the following components calculated by concentration:

(a) sulfuric acid 2-5g/L;

(b) phosphoric acid 6-10g/L;

(c) Fluoride 3-5g/L;

(d) Corrosion inhibitor 0.001-0.025g/L.

In this preferred embodiment, the sulfuric acid is a strong inorganic acid, which reacts quickly and is highly corrosive, and can quickly remove impurities such as oxides and release agents on the surface of the magnesium alloy, and make the surface of the magnesium alloy have good adhesion. The phosphoric acid is a strong acid in the inorganic medium. Since the corrosivity of sulfuric acid is too strong, phosphoric acid and the sulfuric acid are compounded.

In this preferred embodiment, the fluoride is sodium fluoride, which is used to remove silicon impurities on the surface of the magnesium alloy. In other embodiments, the fluoride may also be potassium fluoride, which is used to react with silicon impurities on the surface of the magnesium alloy to remove silicon impurities.

The model of the corrosion inhibitor is LAN826, which is used to slow down the corrosion of the magnesium alloy surface by inorganic strong acid during the pickling process, and can inhibit the corrosion of the magnesium alloy by metal ions such as iron and copper during the pickling process, so that the surface of the magnesium alloy does not produce Pitting corrosion, and at the same time cooperate with the above-mentioned inorganic acid and fluoride to remove oxides, release agents, silicon impurities and other dirt on the surface of magnesium alloys.

Please refer to Fig. 1, the present invention also provides a magnesium alloy pickling method for carrying out pickling and activation treatment of magnesium alloy materials, comprising the following steps:

Step S11: Degreasing the magnesium alloy material with a degreasing solution to remove grease on the surface of the magnesium alloy;

Step S12: washing the degreased magnesium alloy material with pure water at least once;

Step S13: placing the magnesium alloy material in the above pickling solution for pickling activation treatment, the treatment temperature is at room temperature, and the treatment time is between 60-120 seconds;

Step S14: ultrasonically washing the magnesium alloy material with pure water to remove impurities on the surface of the magnesium alloy;

Step S15 : washing the magnesium alloy after ultrasonic pure water washing at least once again with pure water.

Afterwards, the surface conditioning treatment can be performed on the magnesium alloy material after pickling and activation to make the surface of the magnesium alloy uniform, which is conducive to the progress of the chemical formation reaction and the uniformity of the film; Anti-corrosion film.

The following specific examples are given to illustrate the magnesium alloy surface conditioning treatment solution and method of the present invention.

Example 1

First, after the magnesium alloy material is degreased and washed with water, the magnesium alloy material is placed in a pickling solution formulated according to the following composition concentration:

(a) sulfuric acid 4g/L;

(b) phosphoric acid 6g/L;

(c) Sodium fluoride 4g/L;

(d) Corrosion inhibitor 0.020g/L;

Secondly, the magnesium alloy material is subjected to pickling and activation treatment, the treatment temperature is at room temperature, and the treatment time is 70 seconds;

Finally, surface conditioning treatment and chemical conversion treatment are performed on the magnesium alloy material after the pickling treatment.

The atomic percentage (Atomic%) of the silicon element content of the magnesium alloy material after the pickling and activation treatment was tested at each stage of surface treatment by using the above pickling solution, and the results are as follows:

Degreasing Pickling activation treatment Surface treatment Chemical treatment 0.75% 0.24% 0.20% 0.01%

From the analysis of the test results, the silicon content of the magnesium alloy material after the degreasing treatment is 0.75%. The silicon content on the surface is only 0.01%, so the silicon impurities are basically removed.

Example 2

First, after the magnesium alloy material is degreased and washed with water, the magnesium alloy material is placed in a pickling solution formulated according to the following composition concentration:

(a) Sulfuric acid 3g/L;

(b) phosphoric acid 8g/L;

(c) Sodium fluoride 3.5g/L;

(d) Corrosion inhibitor 0.015g/L;

Secondly, the magnesium alloy material is subjected to pickling and activation treatment, the treatment temperature is at room temperature, and the treatment time is 100 seconds;

Finally, surface conditioning treatment and chemical conversion treatment are performed on the magnesium alloy material after the pickling treatment.

The atomic percentage (Atomic%) of the silicon element content of the magnesium alloy material after the pickling and activation treatment was tested at each stage of surface treatment by using the above pickling solution, and the results are as follows:

Degreasing Pickling activation treatment Surface treatment Chemical treatment 0.75% 0.26% 0.19% 0.01%

From the analysis of the test results, the silicon content of the magnesium alloy material after the degreasing treatment is 0.75%. After the pickling and activation treatment with the above pickling solution, the silicon content drops to 0.26%. The silicon content on the surface is only 0.01%, so the silicon impurities are basically removed.

The magnesium alloy pickling solution and method of the present invention use a mixture of inorganic strong acid and fluoride, so it does not contain chromium, has no pollution to the environment, and the solution reacts quickly, and can quickly remove oxides and release agents on the surface of the magnesium alloy. and silicon impurities, and the surface of the magnesium alloy has good adhesion.

Claims (8)

1. A magnesium alloy pickling solution for carrying out pickling and activation treatment to a magnesium alloy material, with water as solvent, comprising the following components calculated by concentration: (a) Sulfuric acid 2-5g/L; (b) phosphoric acid 6-10g/L; (c) Fluoride 3-5g/L. 2. The magnesium alloy pickling solution according to claim 1, further comprising a corrosion inhibitor of 0.001-0.025g/L. 3. The magnesium alloy pickling solution according to claim 2, characterized in that: the fluoride is sodium fluoride. 4. magnesium alloy pickling solution as claimed in claim 3 is characterized in that: take water as solvent, comprise the following components calculated by concentration: (a) Sulfuric acid 4g/L; (b) phosphoric acid 6g/L; (c) Sodium fluoride 4g/L; (d) Corrosion inhibitor 0.020g/L. 5. magnesium alloy pickling solution as claimed in claim 3 is characterized in that: take water as solvent, comprise the following components calculated by concentration: (a) Sulfuric acid 3g/L; (b) phosphoric acid 8g/L; (c) Sodium fluoride 3.5g/L; (d) Corrosion inhibitor 0.015g/L. 6. A magnesium alloy pickling method for carrying out pickling and activation treatment to a magnesium alloy material, comprising the following steps: Degreasing the magnesium alloy material to remove grease on the surface of the magnesium alloy; The degreased magnesium alloy material is placed in a magnesium alloy pickling solution for pickling activation treatment. The magnesium alloy pickling solution uses water as a solvent and includes the following components calculated by concentration: 2-5g/L sulfuric acid, 6-10g/L phosphoric acid and 3-5g/L fluoride, the treatment temperature is at room temperature, and the treatment time is between 60-120 seconds; and The magnesium alloy material was subjected to ultrasonic pure water washing. 7. The magnesium alloy pickling method according to claim 6, characterized in that: the magnesium alloy pickling solution further includes 0.001-0.025g/L corrosion inhibitor. 8. The magnesium alloy pickling method according to claim 6, characterized in that: the fluoride in the magnesium alloy pickling solution is sodium fluoride.

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