JPH0338947B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a method for producing a composite brazed member that is lightweight, has a high cooling effect, and is suitable for use as, for example, a reflector for a carbon dioxide laser or a heat-reflecting wall material for a vacuum furnace. It is related to. [Prior art] Conventionally, for example, as a reflecting mirror for a carbon dioxide laser, a pure Cu surface with a mirror finish,
Furthermore, those with Au plating applied to this surface are also used. However, with these pure Cu reflectors,
As the laser irradiation time becomes longer, metal and non-metal vapors generated from the processed material will deposit on the mirror surface, reducing its reflectance, and the mirror surface will absorb the laser energy and melt, causing reflections. Accidents such as damaging mirrors begin to occur. To prevent such accidents, it is necessary to periodically remove deposits from the mirror surface, but since the pure Cu and Al plating that makes up the reflector is very soft,
The mirror surface was easily damaged when wiping it off, often impairing its reflective properties. For these reasons, in recent years, the use of hard metals Mo and W as materials for carbon dioxide laser reflectors instead of pure Cu has become commonplace. As the reflecting mirror made of metal Mo or metal W, single-crystal mirrors and polycrystal mirrors with fine crystal grains are particularly excellent because they have less adhesion of evaporated substances. [Problems to be solved by the invention] On the other hand, since carbon dioxide laser devices are installed not only in ground equipment but also in space stations, there is a growing demand for the device itself to be lightweight. Along with this, there is a strong desire to reduce the weight of reflective mirrors made of metal Mo or metal W, which have a large specific gravity, that is, are heavy. [Means for Solving the Problems] Therefore, from the above-mentioned viewpoint, the present inventors developed metal Mo members such as reflectors for carbon dioxide lasers and heat reflecting wall materials for vacuum furnaces, Mo alloy members, Furthermore, we focused on metal W members and W alloy members and conducted research to reduce their weight.
A part of a member made of any one of Mo alloy, metal W, and W alloy is made of lightweight pure Al or Al alloy, while, for example, metal Mo and pure Al have a specific gravity (metal Mo is 10.2, pure Al is 2.7), thermal expansion coefficient (metallic Mo is 5×10 ^-6 /℃, pure Al is 23.3×10 ^-6 /℃),
and thermal conductivity (metal Mo is 0.35 cal/cm-s-
℃, pure Al is 0.53 cal/cm-s-℃), and it is extremely difficult to braze these two parts with high bonding strength. , Mo alloy, metal W, and W alloy. A thin film of Al-Si alloy is formed on the brazing surface of a member made of any one of the following: Si:6~ 14% by weight
(Hereinafter, % indicates weight %) When vacuum brazing is performed using a brazing filler metal made of Al-Si alloy containing
These parts have a base made of pure Al or Al alloy,
They obtained the knowledge that brazing can be performed with extremely high bonding strength. This invention was made based on the above findings, and is based on the fact that an average layer thickness of 0.1 to 70 μm is applied to the brazing surface of a member to be brazed made of any one of metal Mo, Mo alloy, metal W, and W alloy. A thin Al-Si alloy thin film is formed, and then a thin film diffusion treatment is performed on the parts to be brazed on which the thin film is formed, under heating conditions of 670 to 850°C in a vacuum or non-oxidizing atmosphere. Subsequently, this member to be brazed is vacuum brazed to a pure Al or Al alloy base via a thin film diffusion layer using a brazing material made of an Al-Si alloy containing 6 to 14% Si. This method is characterized by a method of manufacturing a composite brazing member consisting of the following. In addition, in the method of this invention, the average layer thickness of the Al-Si alloy thin film is limited to 0.1 to 70 μm because
If the average layer thickness is less than 0.1 μm, the thin film diffusion layer may be too thin or may not exist in some areas, making it difficult to secure the desired bonding strength. On the other hand, if the average layer thickness exceeds 70 μm, This is because when a thin film is formed by sputtering or the like, the generated internal residual strain causes the thin film to peel off from the surface of the member to be brazed during the thin film diffusion process. In addition, the thin film diffusion treatment temperature was set at 670 to 850°C because if the temperature is less than 670°C, the diffusion between the thin film and the brazed component will be insufficient, making it impossible to secure the desired brazing joint strength. while its temperature is 850
When the temperature exceeds ℃, the diffusion reaction of the thin film progresses too much,
This is because the brazability of the brazing surface of the member to be brazed with the base body is reduced. Furthermore, the Si content of the brazing filler metal is limited to 6 to 14% because if the Si content is less than 6%, the melting point of the brazing filler metal becomes too high and requires a brazing temperature higher than the melting point of the base material. On the other hand, even if the content exceeds 14%, the melting point of the filler metal may exceed 650℃, and brazing may become impossible. This is based on the reason that the joint strength of the parts is significantly reduced. [Example] Next, the method of the present invention will be specifically explained with reference to Examples. Prepare parts to be brazed that have dimensions of diameter: 100 mm x thickness: 2 mm and have the compositions shown in Table 1, and place a regular planar magnetron on one side of these parts. Using sputtering equipment, atmosphere: Ar, atmospheric pressure: 1 x 10 ^-3 torr, target: various Al-Si alloys with dimensions of 100 mm in diameter x 5 mm in thickness, distance between brazing member and target: 60 mm. , Sputtering voltage: 2000V, Sputtering power: 1.5KW, Time: A predetermined time within the range of 8 seconds to 90 minutes, under the following conditions, an Al-Si alloy thin film having the composition and average layer thickness shown in Table 1 was formed. form, then
Pressure: 5 on the parts to be brazed with these thin films formed.
After performing thin film diffusion treatment in an Ar atmosphere of ×10 ^-6 torr under the conditions shown in Table 1, a wax having dimensions of diameter: 100 mm x thickness: 0.3 mm having the composition also shown in Table 1 is formed. The material to be brazed is placed on the upper surface of a substrate having the composition shown in Table 1 and having dimensions of 100 mm in diameter and 18 mm in thickness, via the brazing material and the thin film diffusion layer. Methods 1 to ⁵ of the present invention and Comparative methods 1 to 5 were each carried out. In addition, Comparative Methods 1 to 5 were carried out under conditions in which one of the conditions constituting the present invention (the conditions marked with an asterisk in Table 1) was outside the scope of the present invention. Then, the shear strength at the brazed portion of the resulting composite brazed member was measured. The measurement results are also shown in Table 1.

〔Effect of the invention〕

From the results shown in Table 1, in Methods 1 to 5 of the present invention, members made of any one of metal Mo, Mo alloy, metal W, and W alloy, which were conventionally considered impossible to braze. And, pure Al also
It is clear that it is possible to braze with a member made of an Al alloy with strong joint strength. On the other hand, as seen in Comparative Methods 1 to 5, it can be seen that if any of the conditions deviates from the scope of the present invention, good bonding strength cannot be obtained. As mentioned above, according to the method of the present invention, metal
Part of a heavy member made of Mo, Mo alloy, metal W, or W alloy is replaced with light pure Al
Alternatively, since it is possible to replace the structure with Al alloy, it is possible to reduce the weight of these heavy components, and since pure Al and Al alloy have excellent cooling effects,
When the resulting composite brazed parts are used, for example, as reflective mirrors for carbon dioxide lasers or heat-reflecting wall materials for vacuum furnaces, they exhibit excellent performance over a long period of time, resulting in industrially useful effects. is brought about.

Claims (1)

[Claims] 1. An Al-Si alloy thin film having an average layer thickness of 0.1 to 70 μm on the brazing surface of a member to be brazed made of any one of metal Mo, Mo alloy, metal W, and W alloy. This thin-film-formed brazing member is subjected to thin-film diffusion treatment by heating at a temperature of 670 to 850°C in a vacuum or non-oxidizing atmosphere. A composite brazing member characterized by vacuum brazing to a pure Al or Al alloy substrate via a diffusion layer using a brazing filler metal made of an Al-Si alloy containing 6 to 14% by weight of Si. Manufacturing method.