JPH0827584A - Method for cleaning and surface-treating metallic material - Google Patents

Abstract

PURPOSE:To remove contaminants in the oxide film on the surface of a metallic material by irradiating the surface of a component material of an equipment such as vacuum vessel, semiconductor manufacturing equipment, medicinal equipment, etc., with a laser beam. CONSTITUTION:In this method, the surface of a metallic material is irradiated with a laser beam having a 10 to 100J/mm<2> energy density to clean it. Preferably, the oxide film present on the surface of the material is once removed with the laser beam irradiation and thereafter, a new oxide film contg. no contaminant is formed. Also, the water repellency of the surface of the material can be enhanced with this laser beam irradiation. At the time of treating an aluminum material 1, the surface of the oxide film 2 is irradiated with a laser beam 4 through a lens 3 while adjusting the energy per shot to 215J/pulse. By repeating this laser beam irradiation, contaminants 5 are removed in a short time, however, since the cleaning effect by irradiation varies with the energy density, preferably, the focal length is changed as indicated by arrows 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an accelerator, a synchrotron radiation device,
TECHNICAL FIELD The present invention relates to a method for cleaning a metal material used in a vacuum container such as an analyzer, a semiconductor manufacturing apparatus, a pharmaceutical device, and the like with a laser, and a surface treatment method for enhancing the water repellency of the surface of the vacuum container and the food-related container.

[0002]

Generally, an accelerator, a synchrotron radiation device, an analyzer,
The metal member in semiconductor manufacturing equipment, pharmaceutical equipment, pharmaceutical manufacturing equipment, etc. must have a clean surface. That is, if the surface of the metal member is contaminated, not only the function of the device is impaired, but also the product may be defective.

Therefore, in order to clean the surface of the metal member, cleaning with acid or electrolytic polishing is performed. In addition, pickling and solvent (alcohol, acetone, etc.), electropolishing to increase the degree of vacuum on stainless steel, complex electropolishing, and aluminum alloy processing using alcohol and processing in atmospheric gas are performed. In such a surface treatment, a large amount of water is adsorbed on the surface of the material, and a large amount of water molecules are incorporated in the film formed on the surface.For example, in a vacuum container, heating is performed to increase the degree of vacuum. Degassing is being carried out to drive out water molecules. The heating degassing process is performed every time the vacuum container is opened to the atmosphere.

[0004]

By the way, there is an oxide film on the surface of the metal member, and the oxide film contains contaminants.
Not only could the contaminants in the oxide film be unable to be removed, but there were cases where the oxide film was contaminated by forming hydroxides.

Further, the heat degassing treatment has a problem that when a high vacuum or higher is required, it takes a very long time to start up the vacuum. The present invention, in consideration of the above-mentioned conventional problems, a method for cleaning a dry metal material capable of surely removing contaminants remaining on the surface of a metal member and an oxide film,
An object of the present invention is to provide a surface treatment method for a metal material, which can remove water molecules taken in on the surface of the metal material in a short time to enhance water repellency.

[0006]

In order to achieve the above-mentioned object, a method for cleaning a metal material according to the present invention comprises:
Energy density of laser light is 10 J / mm ^{2 to} 100 J /
The method for cleaning the metal material is to irradiate with mm ² .

Further, the method for cleaning a metal material according to the present invention is such that the oxide film on the surface of the metal material is irradiated with laser light to remove the oxide film, and then a new oxide film is formed on the surface of the metal material. Cleaning method

Furthermore, the surface treatment method for a metal material of the present invention comprises irradiating the surface of the metal material with a laser beam,
The water repellency of the material surface shall be enhanced.

[0009]

According to the above-mentioned method for cleaning a metal material, contaminants existing in the oxide film on the metal surface are removed by laser irradiation, and inclusions are often present at the grain boundaries of the metal material which serve as nests of the contaminants. For example, intermetallic compounds and non-metallic inclusions can be removed.

Furthermore, by removing the oxide film by laser irradiation, contaminants can be removed upside down, and by forming a new oxide film free of contaminants, it can be used in accelerators, semiconductor manufacturing equipment, pharmaceutical equipment, etc. It will be a useful metal material.

Further, the surface treatment method for the metal material is such that the surface of the metal material is exposed in the atmosphere by irradiating with a laser beam.
It is possible to form a dense oxide film in which water molecules are separated, which can enhance water repellency. For example, in a vacuum container, heating degassing treatment can be eliminated or treated in a short time, and high vacuum degree can be achieved. Can be obtained. Alternatively, in a food container, corrosion resistance can be improved by increasing water repellency.

[0012]

EXAMPLES Examples of the method for cleaning a metal material according to the present invention will be described below. In FIG. 1, 1 is an aluminum material. This aluminum material 1 is extruded in an argon atmosphere and has an oxide film 2 on its surface. Then, some contaminants remain on the surface of the oxide film 2.

The laser light 4 is applied to the aluminum material 1 through the lens 3. More specifically, 5 x 20 m
The laser beam 4 is irradiated through a mask (not shown) having a beam passage hole of m, and the energy per shot is 215 joules / pulse. The most favorable condition was 52 Joules / mm ² , and the proper energy density range was 10 to 100 Joules / mm ² .

Outside this range, for example, when the joule is 130 joules / mm ² , the surface of the metal material is melted and the metal material is damaged, which is inconvenient. By repeating the irradiation of the laser beam 4 in the range of the appropriate energy density, the desired contaminants could be removed. Since the cleaning effect by irradiation changes depending on the energy density, it is preferable to change the focal length as shown by 6 in FIG.

The evaluation of the above laser cleaning was carried out by optical microscope observation and Auger analysis, and it was as follows. First, in an optical microscope observation, although not shown as an observation image, the laser irradiation portion has a high surface light brightness,
It was confirmed that the surface contaminants were removed and the crystal grain boundaries were also cleaned. On the other hand, it was confirmed that the laser non-irradiated portion had low light brightness and surface contaminants remained. Observing the case where the energy density was too high, the surface was melted and the cleaning effect was poor.

Next, FIGS. 2 and 3 show the results of Auger analysis before and after laser irradiation. FIG. 2 shows an Auger analysis result of the aluminum material before laser irradiation, and FIG. 3 shows an Auger result of the aluminum material after laser irradiation. As shown in the figure, compared to before laser irradiation, carbon C, which is an impurity, was extremely reduced after laser irradiation, and surface contamination was drastically reduced to form a new thick oxide film without contamination. Can be seen.

Next, one embodiment of the surface treatment method for enhancing the water repellency of the metallic material according to the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 shows a schematic configuration of an experimental apparatus used in the atmosphere, and 11 is a 50 W infrared CO ₂ laser beam 1
The laser beam 12 oscillated from the laser oscillator 11 oscillates 2 through the condensing lens 13 on the rotary movement holder 14 whose rotation axis is inclined by 45 ° (metal material to be processed (metal material). ) 15 is irradiated onto the surface of the laser beam 15, and the rotary movement holder 14 is moved left and right by a driving device (not shown) and rotated and scanned so that the laser beam 12 is uniformly irradiated. Reference numeral 16 is a reflected light trap plate.

Here, an aluminum alloy is used for the metal material 15 to be treated, the surface of which is pre-wetted with water, and the surface of the metal material 5 is irradiated with the laser beam 12 for 1 minute or less and 2 minutes or more. Processed. Water repellency was judged by observing the spread state of the water droplets with a microscope by dropping water droplets on the surface of the irradiated metal material 15 to be treated and the unirradiated metal material.

As a result, it has been proved that irradiation with laser light enhances the volatility of the surface of the metal material 15 to be treated. It was also found that at the same energy density, the longer the irradiation time, the greater the water repellency.

As shown in FIG. 5, in the metal material 5-1 made of aluminum alloy after rolling, the surface layer (contaminated oxide film) 21 has Al ₂ O ₃ and Al (OH). ) ₃ are mixed, and infrared CO ₂ laser light 1
In case of ₂ , Al ₂ O ₃ + 2Al (OH) ₃ → 2Al ₂ O ₃ +3
This is because it becomes H ₂ O and the densified oxide film layer 22 is formed.

According to the above method, by forming the dense oxide film surface layer 22 on the surface of the metal material 3 to be treated, the water molecules of the surface layer 21 can be evaporated to enhance the water repellency. Therefore, for example, by irradiating the inner surface of the metal vacuum container with the laser beam, the heating and degassing process can be omitted or the predetermined vacuum degree can be achieved by the heating and degassing process for a short time. Further, by irradiating the surface of the metal food container with the laser beam 12, the water repellency can be increased and the corrosion resistance can be improved.

The new oxide film obtained by the cleaning method and the new oxide film obtained by the surface treatment method are the same, and both improved cleaning effect and improved water repellency.

[0023]

As described above, according to the method for cleaning a metallic material of the present invention, since the cleaning of the metallic material is performed by laser light, the cleaning operation is easy and the contaminants remaining on the oxide film are also present. Can be removed together with the oxide film to form a newly cleaned oxide film, so that the cleaning effect is great, and the effect is great as a method for cleaning metal members of equipment and manufacturing equipment that dislike contaminants.

Further, according to the surface treatment method for a metal material of the present invention, by irradiating with a laser beam, a dense oxide film in which water molecules are separated can be formed on the surface of the metal material in the atmosphere. Therefore, the water repellency can be enhanced. Therefore, for example, a vacuum container can be processed in a short time to obtain a high degree of vacuum, and in a food container,
Corrosion resistance can be improved by increasing water repellency.

[Brief description of drawings]

FIG. 1 is an explanatory view of a state in which a method for cleaning a metal material of the present invention is being performed

FIG. 2 is a graph showing an Auger analysis of an aluminum material before laser irradiation.

FIG. 3 is a graph showing an Auger analysis of an aluminum material after laser irradiation.

FIG. 4 is a schematic configuration diagram showing an experimental device for a surface treatment method according to the present invention.

5A is an explanatory view of a surface state of a rolled aluminum material before processing, and FIG. 5B is an explanatory view of a surface state of an aluminum material after laser light irradiation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum material 2 Oxide film 3 Lens 4 Laser light 5 Pollutant 11 Laser oscillator 12 Laser light 13 Condensing lens 14 Metal material to be processed 15 Rotating movable holder 16 Metal material to be processed 21 Surface layer 22 Oxide film surface layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motoko Suzuki, 3-28 Nishikujo 5-chome, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. 3-28, Hitachi Shipbuilding Co., Ltd. (72) Inventor, Jiro Ishibe 5--3-28, Nishikujo, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd.

Claims (3)

[Claims] 1. An energy density of 10 on a surface of a metal material.
The method of cleaning metal material, characterized by irradiating a laser beam of ^{J / mm 2 ~100J / mm 2} . 2. A method for cleaning a metal material, which comprises irradiating a laser beam onto the surface of the metal material to remove an oxide film existing on the surface of the material, and then forming a new oxide film on the surface of the metal film. . 3. A surface treatment method for a metal material, which comprises increasing the water repellency of the surface of the metal material by irradiating the surface of the metal material with laser light.