JP5647073B2 - Surface treatment method of magnesium and magnesium alloy extruded material - Google Patents

Description

  The present invention relates to a surface treatment method for magnesium and magnesium alloy extruded material.

The magnesium alloy extruded material has a die line peculiar to extrusion processing on the surface. Since the die line is non-uniform and poor in design, conventionally, the die line is removed by mechanical processing such as shot blasting or barrel polishing. However, mechanical processing such as shot blasting may cause deformation and dust explosion, and the extruded material having a complicated cross-sectional shape may not be sufficiently uniform in surface.
Patent Document 1 discloses a technique for obtaining a glossy textured surface by chemical treatment in which a magnesium alloy is brought into contact with a treatment solution. However, in this method, since the treatment solution contains iron (chemical blast treatment solution), a process for removing iron is necessary later, and the treatment process is very complicated. Further, if the removal of iron is insufficient, the corrosion resistance decreases due to the remaining iron.

JP 2005-538249 A

  In view of the circumstances described above, an object of the present invention is to provide a surface treatment method of magnesium and a magnesium alloy extruded material that can obtain a uniform surface without a die line with a small number of treatment steps.

Surface treatment method of the magnesium and magnesium alloy extruded material according to the invention of claim 1, wherein in order to attain the aforementioned object, a solution containing a single inorganic acid extruded material magnesium or magnesium alloy, of an inorganic acid concentration a solution comprising the steps of satin the surface in contact with the solution below 4.5 vol% or more 10 vol%, a single inorganic acid extruded material then magnesium or magnesium alloy, the concentration of an inorganic acid Is characterized by having a step of glossing the surface by contacting with a solution of 0.5 vol% or more and less than 4.5 vol%.

The surface treatment method according to claim 1 Magnesium according the invention described and magnesium alloy extruded material, an extruded material of magnesium or magnesium alloy a solution containing a single inorganic acids, the concentration of the inorganic acid or 4.5 vol% 10 vol %, The die line is removed to form a uniform satin finish surface, and the solution further contains a single inorganic acid, and the concentration of the inorganic acid is 0. By the process of making the surface glossy by bringing it into contact with a solution of not less than 5 vol% and less than 4.5 vol%, a textured surface with a metallic feeling can be obtained. Unlike mechanical processing such as shot blasting, it can handle extruded materials with complicated cross-sectional shapes, and there is no risk of deformation or dust explosion. Since the processing solution does not contain a foreign metal such as iron, there is no step of removing the foreign metal, and the processing step can be simplified.

(A) is a photograph of the surface of Example 1, (b) is a photograph of the surface of Comparative Example 1, (c) is a photograph of the surface of Comparative Example 2, and (d) is a photograph of the surface of Comparative Example 3. is there. It is a flowchart which shows the example of the process process of the surface treatment method of this invention.

  Embodiments of the present invention will be described below. In the surface treatment method of magnesium and magnesium alloy extruded material of the present invention, as shown in FIG. 2, first, degreasing is performed to remove oil on the surface, and then contact is made with a solution containing a single inorganic acid. Thus, a satin finish treatment is performed by forming fine irregularities on the surface of the extruded material to make the surface a satin finish. Next, a desmut treatment is performed to remove surface smut. Next, a glossing treatment for improving the metallic appearance of the surface is performed by contacting with a solution containing a single inorganic acid. Next, desmutting is performed again to remove the surface smut. Thereafter, in order to maintain the effect of the surface treatment of the present invention for a long period of time, an anodizing treatment is performed. Note that the anodizing treatment is not necessarily performed.

  The treatment solution used for the satin treatment may be a solution containing a single inorganic acid, and examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid and the like. The concentration of the inorganic acid in the treatment solution may be appropriately adjusted according to the type of inorganic acid, the type of magnesium alloy, and the like, but is preferably 4.5 vol% or more and 10 vol% or less. If the concentration of the inorganic acid is less than 4.5 vol%, the removal of the die line may be insufficient. If it is greater than 10 vol%, the die line is removed, but rough irregularities are formed, resulting in a non-uniform appearance. It is. If the density | concentration of an inorganic acid is 4.5 vol% or more and 10 vol% or less, a die line can be removed reliably and the uniform appearance of a satin finish can be obtained. The temperature of the treatment solution can be set to 5 to 50 ° C., for example, and the time of contact with the treatment solution may be appropriately adjusted according to the concentration and temperature of the inorganic acid, but for example 10 to 1800 sec. Can do. While it is in contact with the treatment solution, it may be unstirred, or may be stirred or ultrasonic waves may be applied.

  The treatment solution used for the brightening treatment may be a solution containing a single inorganic acid, and examples of the inorganic acid include sulfuric acid and phosphoric acid. The concentration of the inorganic acid in the treatment solution may be appropriately adjusted according to the type of inorganic acid, the type of magnesium alloy, etc., but is preferably 0.5 vol% or more and less than 4.5 vol%. When the concentration of the inorganic acid is less than 0.5 vol%, chemical polishing is not sufficient and the appearance of metal is poor, and when it is 4.5 vol% or more, the chemical polishing becomes excessive, and the unevenness obtained in the matte finishing process is It is because it will be smoothed. If the concentration of the inorganic acid is 0.5 vol% or more and less than 4.5 vol%, it can be appropriately chemically polished while leaving the satin-like irregularities, and a beautiful satin-like appearance rich in metal feeling can be obtained. The temperature of the treatment solution can be, for example, 5 to 50 ° C., and the time for which the treatment solution is kept in contact with the treatment solution may be appropriately adjusted according to the concentration and temperature of the inorganic acid, for example, 10 to 1200 sec. Can do. While it is in contact with the treatment solution, it may be unstirred, or may be stirred or ultrasonic waves may be applied. In the brightening treatment process, the unevenness (pear finish) formed on the surface of the magnesium and magnesium alloy by the matte finish should not be dissolved so as to be smooth, and the amount of magnesium dissolved is [satin finish> gloss finish] The processing conditions are adjusted so that

  The degreasing and desmutting treatments may be treatments generally used for surface treatment of magnesium alloys. Note that the degreasing and desmutting treatments may be omitted.

Examples of the present invention and comparative examples are shown in Table 1. In each case, an extruded material (70 × 70 × 3 mm) of AZ31 magnesium alloy was used. The presence or absence of was evaluated. The treatment solution for the satin treatment and the gloss treatment is both an aqueous solution and the concentration is vol%.
Comparative Example 1 is one in which neither the satin treatment or the gloss treatment is performed (fabric itself), Comparative Example 2 is the one in which only the gloss treatment is performed, and Comparative Example 3 is the one in which only the satin treatment is performed. .
In both Examples and Comparative Examples, degreasing is performed under general conditions before the matte finish treatment, and desmutting is performed under the general conditions after the matte finish treatment and after the glossing treatment.
The photograph of the surface of Example 1 after a process and the photograph of the surface of Comparative Examples 1-3 are shown in FIG.

  As shown in FIG. 1 (a), Example 1 of the present invention had a satin finish with no fine lines and a uniform surface and a very beautiful surface rich in metallic feeling and gloss. Examples 2 to 6 also had a satin finish surface with a metallic feeling in substantially the same manner as Example 1. In Comparative Example 1 in which neither the satin treatment nor the gloss treatment was performed, as shown in FIG. 1B, the die lines appeared irregularly on the surface, and there was no metal feeling or gloss. In Comparative Example 2 in which only the glossing treatment was performed, as shown in FIG. 1 (c), although there was a metallic feeling and gloss, a die line remained on the surface, and it did not become satin. As shown in FIG. 1 (d), Comparative Example 3 in which only the satin treatment was performed has almost a satin finish without a die line, but the surface unevenness is rougher than that of Example 1, and the metal feeling and There was no luster.

  As described above, according to the surface treatment method of the present invention, it is possible to obtain a clean surface with a satin finish that has no die line, is uniform throughout, and has a metallic feeling. Unlike the mechanical treatment such as shot blasting, the surface treatment method of the present invention can cope with an extruded material having a complicated cross-sectional shape, and there is no fear of deformation or dust explosion. Since the processing solution does not contain a foreign metal such as iron, there is no step of removing the foreign metal, and the processing step can be simplified.

  The present invention is not limited to the embodiments described above. The treatment solution used for the satin treatment may be a solution containing a single inorganic acid, and an inorganic acid other than sulfuric acid, hydrochloric acid, or nitric acid may be used. What is necessary is just to adjust processing time suitably according to it. The treatment solution used for the brightening treatment may be a solution containing a single inorganic acid, and an inorganic acid other than phosphoric acid and sulfuric acid may be used. The concentration can be changed as appropriate, and the temperature and treatment can be changed. What is necessary is just to adjust time suitably according to it. After the glossing treatment, coating may be performed instead of anodic oxidation. The present invention can be used for extruded materials of any magnesium alloy, and can also be used for extruded materials of pure magnesium. The surface-treated magnesium and magnesium alloy extruded material of the present invention can be used in various fields such as automobile parts, electrical appliances, personal computers, mobile phones, and building materials.

Claims (1)

A step of bringing the extruded material of magnesium or a magnesium alloy into a solution containing a single inorganic acid and bringing the inorganic acid concentration into contact with a solution having a concentration of 4.5 vol% or more and 10 vol% or less to make the surface matte; Or having a step of glossing the surface by bringing the extruded material of a magnesium alloy into a solution containing a single inorganic acid and having a concentration of the inorganic acid of 0.5 vol% or more and less than 4.5 vol%. The surface treatment method of the magnesium and magnesium alloy extrusion material characterized.