JPH0441181A - Processing method for vacuum exposed face of metal made work - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for treating a vacuum-exposed surface of a metal workpiece, and more particularly to a method for forming a stable oxide layer on a vacuum-exposed surface.

(Prior Art) Generally, aluminum is oxidized under various conditions to form an oxide layer on its surface. This oxide layer is usually formed as a hydroxide film by water vapor in the air. However, this hydroxide film tends to grow and not only causes cloudiness on the aluminum surface, but also has the effect of absorbing moisture.

For this reason, in an aluminum vacuum container, water is released as outgas from the hydroxide film on the surface, and it is difficult to obtain a high degree of vacuum of about 10''1° Torr due to the volumetric expansion of this water.

Therefore, conventionally, when manufacturing vacuum containers from aluminum, when extruding or machining the aluminum, the forming and processing was done without lubrication and in a mixed gas of an inert gas such as argon and oxygen. By this method, an oxide film (A1203) is formed on the virgin surface of aluminum that appears during processing and molding using oxygen while removing non-oxygen components such as moisture in the air with an inert gas, and this stable oxide film creates a stable oxide film. It is known to improve vacuum performance by eliminating moisture release in vacuum.

(Problem to be solved by the invention) However, this method requires advanced technology to form or process aluminum without using lubricating oil, making it difficult to perform processing that generates a large amount of heat or complex processing, and is expensive. There was a problem in that a dedicated device was required and the cost of the product was high.

The present invention has been made in view of the above, and its purpose is to treat the vacuum-exposed surface of a vacuum workpiece made of metal such as aluminum using a predetermined method. The purpose is to form a stable oxide layer on an exposed surface at low cost.

(Means for Solving the Problems) In order to achieve the above object, the present invention exposes the virgin surface on the metal surface by glass bead blasting, and performs the blasting using the same inert gas and oxygen as above. A stable oxide film was formed on the virgin surface by performing the process in a mixed gas with

Specifically, the method of the present invention involves performing glass bead blasting by blowing glass beads with a mixed gas of inert gas and oxygen onto the vacuum-exposed surface of a vacuum workpiece such as a vacuum container. The method is characterized in that an old oxide layer is removed to expose a virgin metal surface, and at the same time a new oxide layer is formed on the virgin metal surface.

(Function) With the above configuration, in the present invention, glass beads are sprayed onto the vacuum-exposed surface of a metal workpiece using a mixed gas of inert gas and oxygen to form an oxide layer, so this blasting treatment is performed after processing. What is necessary is to apply it to the workpiece, and general methods can be used for processing and shaping the workpiece. Therefore, an expensive and dedicated device is not required, and a stable oxide layer can be formed at low cost.

Further, a virgin metal surface is exposed on the exposed metal surface by glass bead blasting, and a new oxide layer is formed on the virgin metal surface by oxygen in the gas, so that the oxide layer becomes a stable oxide layer. Therefore, when the workpiece is exposed to vacuum, gas occlusion on the vacuum-exposed surface, which hinders achieving a high degree of vacuum, can be effectively suppressed, and the effect can be stably maintained over a long period of time.

(Example) Embodiments of the present invention will be described below based on the drawings.

In this example, an aluminum vacuum container (work)
In this case, an oxide film is formed on the inner surface (vacuum-exposed surface) of a vacuum vessel.The vacuum vessel is, for example, a sealed cylindrical one, which is formed by extrusion molding and then subjected to welding and various machining processes. At this time, extrusion molding, machining, etc. are carried out in a conventional manner by spraying a lubricating oil for processing.

Next, in the final step after all of these processes are completed, as shown in FIG. Glass beads B are sprayed with a mixed gas G of argon gas and oxygen to perform glass bead blasting. The glass bead blasting device 2 has a nozzle 3 that can be held by an operator or moved by a machine, and this nozzle 3 has an inner tube 4 and an outer tube arranged concentrically at a constant interval on the outside of the inner tube 4. It has a double structure with the tube 5. A blast passage 6 is formed inside the inner tube 4,
This blast passage 6 is located at the left end of the figure or at the jet port 6a. The blast passage 5 is connected via a mixing device 8 to a blast supply device 9 and a high pressure gas supply device 10 . The high-pressure gas supply device 10 compresses a mixed gas G of argon gas Ar as an inert gas and oxygen 02 to a high pressure. The glass beads B are mixed with the glass beads B, and the glass beads B are ejected from the jet port 6a through the blast passage 6 by the gas pressure of the mixed gas G, and are sprayed onto the inner surface 1a of the vacuum container 1 at high speed.

On the other hand, the space between the inner tube 4 and the outer tube 5 is a gas passage 7, and the left end of this gas passage 7 in the figure is the ejection lower a. The gas passage 7 is connected to the high-pressure gas supply device 10, and the mixed gas G from the gas supply device 10 is blown out around the glass bead blast B from the outlet 6a of the blast passage 6.

Then, as shown in FIG. 1, the blast passage 6 of the nozzle 3
By spraying glass beads B onto the inner surface 1a of the vacuum container 1, the old oxide layer formed on the inner surface 1a of the container 1 after processing is removed to expose the virgin metal surface, and almost at the same time, the virgin metal surface is Oxygen 02 in mixed gas G
to form a new oxide layer.

Therefore, in this embodiment, the glass beads B are blown onto the inner surface 1a of the aluminum vacuum container 1 using a mixed gas G of argon gas Ar and oxygen 02 to form an oxidized layer on the exposed surface. may be applied to the processed container 1, and general methods can be used for processing and molding the vacuum container 1. Therefore, an expensive and dedicated device is not required, and a stable oxide layer can be formed at low cost.

In addition, the inner surface 1 of the container 1 is
A virgin metal surface is exposed at point a, and a new oxide layer is formed on the virgin metal surface by oxygen 02 in the gas. Moreover, at this time, the inner surface 1a of the container 1, whose virgin metal surface is exposed by the glass bead blast B from the nozzle 3, is exposed not only to the mixed gas G blown out from the blast passage 6 together with the blast, but also to the lower blowout of the gas passage 7. Since it is also covered with the mixed gas G blown out from a, there is no risk of moisture in the air coming into contact with the inner surface 1a. As a result, the oxide film becomes an extremely stable oxide layer, which can effectively suppress gas occlusion on the inner surface 1a, which hinders achieving a high degree of vacuum, and can maintain this effect stably over a long period of time. .

Incidentally, the inert gas forming the mixed gas G is argon gas A.
It goes without saying that other gases than r may be used.

Further, in the above embodiment, the inner surface 1a of the vacuum container 1 is treated, but the same treatment can be performed on the vacuum-exposed surface of a component that is exposed to vacuum.

Furthermore, the present invention can also be applied to maintenance and inspection of vacuum containers and parts. Furthermore, the present invention can be similarly applied to other metals other than aluminum, such as copper, iron, and stainless steel, which form an oxide film that easily absorbs gas in the air.

(Effects of the Invention) As explained above, according to the present invention, by performing glass bead blasting on the vacuum-exposed surface of a metal workpiece with a mixed gas of inert gas and oxygen, the vacuum-exposed surface of the metal workpiece can be treated at low cost. A stable oxide film can be formed, and gas occlusion on the vacuum-exposed surface, which hinders the achievement of a high degree of vacuum, can be prevented for a long period of time, making it possible to achieve both a high degree of vacuum and cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a processing state according to an embodiment of the present invention. 1... Vacuum container (work) 1a... Inner surface (vacuum exposed surface) 2... Glass bead blasting device 3... Nozzle G... Mixed gas of argon gas (inert gas) and oxygen B. ··Glass beads

Claims (1)

[Claims] (1) By performing glass bead blasting on the vacuum-exposed surface of a metal workpiece using a mixed gas of inert gas and oxygen, the old oxide layer on the exposed surface is removed and the virgin metal surface is exposed, and at the same time A method for treating a vacuum-exposed surface of a metal workpiece, which is characterized by forming a new oxide layer on a virgin metal surface.