JPH028828B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention relates to a method for manufacturing 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 an inner wall material for a vacuum furnace. It is. [Prior Art] Conventionally, for example, as a carbon dioxide gas reflecting mirror, a mirror-finished pure Cu surface or a mirror-finished surface, or a mirror plated with Au plating, etc., have been used. However, with these Cu reflectors, when the laser irradiation time becomes long, metal and non-metal vapors generated from the processed materials are deposited on the mirror surface, which not only reduces the reflectance, but also causes the mirror surface to be exposed to the laser. Accidents have occurred in which the mirror absorbs energy and melts, damaging the reflector. To prevent such accidents, it is necessary to regularly remove deposits from the mirror surface, but since the pure Cu and Au plating that makes up the reflective mirror is very soft, it is easy to damage the mirror surface when wiping it off. , the reflective properties were frequently impaired. For this reason, in recent years, hard Mo has been used as a material for carbon dioxide laser reflectors instead of pure Cu.
The use of . As for this Mo reflector, single-crystal ones and polycrystal ones with fine crystal grains exhibit excellent performance with less adhesion of evaporated matter. [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 Mo reflectors that have a high specific gravity (heavy). [Means for Solving the Problems] Therefore, from the above-mentioned viewpoint, the present inventors developed Mo members such as Mo reflectors, Mo alloy members, and similar heavy W members and W alloys. As a result of focusing on components and conducting research to measure their weight ratios, we found that some components made of pure Mo, Mo alloy, pure W, and W alloy are lightweight (low specific gravity). Composed of pure Al or Al alloy, while
For example, the specific gravity of pure Mo and pure Al (pure Mo: 10.2, pure
Al: 2.7), thermal expansion coefficient (pure Mo: 5×10 ^-6 /℃, pure
Al: 23.3×10 ^-6 /℃), and thermal conductivity (pure Mo:
0.35cal/cm-s-℃, pure Al: 0.53cal/cm-s-
It is extremely difficult to braze these two parts with high bonding strength because their properties differ significantly in various respects such as
The brazing surface of a member made of either pure W or W alloy is coated with an average layer thickness in advance by known means such as ion plating or plating.
A Cu layer of 0.01 to 50 μm is fixedly formed, and in this state, a pure Al or Al alloy member is sandwiched between the Cu layer and a brazing filler metal made of an Al alloy containing 6 to 14% by weight of Si. They discovered that if they are placed over the brazing surface and heated in a vacuum, brazing with high bonding strength is possible. This invention was made based on the above knowledge, and is based on the above-mentioned findings. A Cu layer is fixedly formed in advance, and the member to be brazed is made of pure Al or an Al alloy using a brazing material made of an Al alloy containing 6 to 14% by weight of Si, via the Cu layer. This method is characterized by a method for manufacturing a composite brazing member that is vacuum brazed to a base. In addition, in the method of this invention, the average layer thickness of the Cu layer is limited to 0.01 to 50 μm because if the average layer thickness is less than 0.01 μm, it is not possible to secure the desired bonding strength. This is based on the reason that if the thickness exceeds 50 μm, the internal residual strain generated during the formation of the Cu layer causes the Cu layer to peel off from the brazing surface of the component to be brazed during brazing. Similarly, regarding the Si content of the filler metal, if the content is less than 6% by weight, the melting point of the filler metal will be too high, exceeding 660°C, and a brazing temperature higher than the melting point of the base material may be required. As a result, brazing becomes impossible in some cases, and even if the content exceeds 14% by weight, the melting point of the brazing filler metal often exceeds 660°C. The content should be reduced to 6 to 14% by weight, as the reaction with the parts to be brazed would become significant and cause erosion.
It was established that [Example] Next, the method of the present invention will be explained with reference to an example. Each member to be brazed has the composition shown in Table 1, and diameter: 200 mm x thickness: 2 mm.
Prepare various members with the dimensions of , and pre-coat one side of the member to be brazed with a layer of Cu having the average layer thickness also shown in Table 1 using the forming means shown in Table 1.
The layer is fixedly formed, and then this member to be brazed is placed on the upper surface of a substrate having the composition shown in Table 1 and dimensions of 200 mm in diameter and 18 mm in thickness, with the Cu layer interposed therebetween. , a brazing filler metal made of an Al alloy having the composition and average layer thickness shown in Table 1 was stacked on top of each other, a 3 kg weight was placed on top of the brazing filler metal, and in a vacuum of 1×10 ^-5 torr,
to a predetermined temperature within the range of 600-630℃

【table】

〔Effect of the invention〕

From the results shown in Table 1, in methods 1 to 8 of the present invention, pure Mo, Mo alloy, pure W, which were conventionally considered to be extremely difficult to join by brazing,
and a member made of any one of W alloy,
It is clear that a member made of pure Al or an Al alloy can be brazed with strong bonding strength. As mentioned above, according to the method of this invention, pure
Part of a heavy member made of Mo, Mo alloy, pure W, or W alloy is replaced with light pure Al
Or it can be replaced with Al alloy, so
It is now possible to reduce the weight of various heavy components, making it even more pure.
Al or Al alloy has an excellent cooling effect, so
For example, when applied to the manufacture of reflectors for carbon dioxide lasers and inner wall materials for vacuum furnaces, these materials exhibit industrially useful effects such as superior performance over a long period of time.

Claims (1)

[Claims] 1. A Cu layer having an average layer thickness of 0.01 to 50 μm is fixedly formed on the brazing surface of a member to be brazed made of pure Mo, Mo alloy, pure W, or W alloy. Then, this member to be brazed is vacuum brazed to a base made of pure Al or an Al alloy through the Cu layer using a brazing material made of an Al alloy containing 6 to 14% by weight of Si. A method for manufacturing a composite brazing member characterized by: