JPH0354802B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a titanium evaporation line used in a nuclear fusion device. Nuclear fusion devices are being developed that attempt to make the nuclei of light elements, such as deuterium and tritium, collide with each other to cause a fusion reaction, and utilize the large amount of energy released at that time. In a nuclear fusion device, it is necessary to confine plasma in a vacuum container and heat it to a high temperature.In order to prevent the plasma from coming into direct contact with the vacuum container, the first wall directly facing the plasma is made of carbonized Must be coated with titanium (TiC). The above-mentioned titanium carbide is obtained by heating and evaporating titanium in a hydrocarbon gas atmosphere such as acetylene gas. That is, the following reaction 2Ti+C ₂ H ₂ →2TiC+H ₂ is caused to occur on the surface of the first wall, so that the titanium carbide film is coated on the surface of the first wall. As a titanium source, a titanium evaporation wire with a tungsten wire as a core and a titanium wire wound around the core is being used. Attempts have been made to evaporate titanium by applying electricity and utilizing the difference in their melting points, boiling points, etc. In this case, the operating cost required for evaporating titanium can be reduced as the amount of titanium evaporated at one time is large, and for this purpose, it is said that the amount of titanium loaded and the evaporation effect must be high. Regarding the conventional titanium evaporation wire mentioned above, that is, one in which a titanium wire is wound around a single tungsten wire,
The amount of titanium loaded is said to be limited to about 0.7g, and the titanium evaporation effect is only about 20% of that amount, and the remaining 80% is discarded as unevaporated titanium, and there are disadvantages such as wire breakage during evaporation of titanium. It was hot. Additionally, in general, tungsten materials have the property that once they have been subjected to a thermal history of approximately 1000°C or higher, their mechanical strength becomes extremely weak. Therefore, with a titanium evaporation wire that has only a combination of titanium and tungsten core, if you touch the evaporation wire to remove a used titanium evaporation wire, the tungsten core will break and fall off. There was also the problem that it was really troublesome to handle. This invention was conceived based on the above, and utilizes the differences in recrystallization, melting point, boiling point, and evaporation of tungsten, molybdenum, and titanium.
Overall, the weight balance of each substance is good, high voltage,
The present invention aims to provide a titanium evaporation wire that can withstand high current and high temperature, does not cause disconnection during titanium evaporation, and has a high titanium loading and evaporation effect. Further, the present invention provides an extremely economical titanium evaporation line that can prevent dripping of molten titanium that occurs with an increase in the amount of titanium loaded, and can further improve titanium evaporation efficiency. One of the inventions according to the above-mentioned object is a titanium evaporated wire formed by twisting a plurality of tungsten wires to form a core, and winding a molybdenum wire and a plurality of titanium wires around the core. Another invention resides in a titanium evaporated wire having a guard member made of a molybdenum wire wound around a tungsten strand and a tungsten wire wound around a plurality of titanium wires at required intervals. In the above configuration, the molybdenum wire wound together with the titanium wire is heated by the tungsten core, and the titanium wire is also heated from the side.
The titanium melts more uniformly than heating radially from the center using only the tungsten core. In addition, molybdenum wire is used as a side winding wire for the titanium wire, and tungsten wire is used as a guard member.
Since the molten titanium uniformly wets the heated tungsten core, the tungsten is less likely to become brittle due to localized heating. As a result, the mechanical strength deterioration of the tungsten core due to weakening is reinforced by the molybdenum wire, which is less susceptible to weakening due to thermal history, making it extremely easy to handle the used titanium evaporation wire. The wire diameter of the tungsten wire that becomes the core above is 0.8
The range is preferably from 1.0 m/m to 1.0 m/m, and two or three of them are twisted at three pitches within a size of 12 to 14 m/m. In addition, the wire diameter of molybdenum wire is
Range of 0.5 to 10φm/m, titanium wire is 0.8 to 1.2φm/
Preferably, m ranges from 12 to
The titanium wire is wound at a ratio of six titanium wires and one molybdenum wire to a size of 15 m/m, forming a titanium evaporation wire with an outer diameter of 2.8 to 2.6 φm/m. Furthermore, the wire diameter of the tungsten wire wound as a guard member is 0.3~
The wire width may be within the range of 0.4 m/m, and the wires are wound at a pitch of 2 to 4 m/m. Next, the present invention will be explained in more detail with reference to illustrated examples. In the figure, 1 is a tungsten wire, 2 is a molybdenum wire,
3 is a titanium wire. The example shown in Fig. 1 and Fig. 2 is 2 mm of 1.0φm/m.
The length of the tungsten wire 1,1 is 12m/m _{l 1}
A core A is formed by twisting the wires at a ratio of three strands in the area, and around the core A, one molybdenum wire 2 of 0.5φm/m and three titanium wires 3 of 1.0φm/m are connected. ,3,
3 and molybdenum wire 2 in a length l ₂ range of 12m/m.
The wire is wound at a ratio of 7 threads including the wire, and the outer diameter is 2.1φm/m.
This shows the titanium evaporation line. Although the front view is omitted in Fig. 3, it shows a longitudinal cross-sectional view of the case where the core body A is formed by twisting three tungsten wires 1, 1, 1 with the same wire diameter as above. . Figures 4 and 5 show a core A made up of three twisted tungsten wires 1, 1, 1 as in Figure 3, one molybdenum wire 2 and three twisted wires as in the above examples. Wind the titanium wires 3, 3, 3, and further wind the 0.4φm/m tungsten wire 4 as guard member B.
This figure shows a titanium evaporation wire wound with m pitch _l3 . Next, examples are shown below.

[Table] In addition, the code in the drawing and the material symbol are shown to indicate the material. Also, the numbers in the table indicate the number of pieces. When the above-mentioned Example ~ _B2 was heated by directly applying electricity of about 10 V and 200 A, it was difficult to disconnect, and the amount of titanium evaporated was at most 90% of the amount of titanium loaded. In addition, in the example, a water dripping phenomenon occurred in titanium, but in the example in which the guard member B was wound.
_B1 , _B2 , _B1 , and _B2 did not cause water droplet dripping,
There was no disconnection during the evaporation of titanium. As a result, a titanium loading of 3g was possible, and about 80% of the loading was evaporated. For comparative study, a titanium evaporation wire was prepared by winding a titanium wire and a molybdenum wire around a tungsten wire with a wire diameter of 0.8 to 0.9φm/m in the same manner as in the example, and evaporation was attempted by applying electricity. A disconnection occurred and the amount of titanium evaporated was less than 1% of the amount of titanium loaded. Therefore, the titanium evaporation line according to the present invention is
It has the characteristics of being superior in titanium loading and titanium evaporation efficiency than conventional products, being able to prevent disconnection during electrical heating, and being economical as the amount of unevaporated titanium that is discarded is extremely small.

[Brief explanation of drawings]

The drawings illustrate the structure of the titanium evaporation wire according to the present invention.
The figure is an enlarged cross-sectional view, and Figure 3 is an enlarged cross-sectional view of a titanium evaporation wire with three tungsten strands as the core.
FIG. 4 is a partially cutaway front view of the titanium evaporation wire around which the guard member is wound, and FIG. 5 is an enlarged sectional view thereof. 1, 4...Tungsten wire, 2...Molybdenum wire,
3...Titanium wire, A...Core, B...Guard member.

Claims (1)

[Scope of Claims] 1. A titanium evaporated wire characterized in that a plurality of tungsten wires are twisted to form a core, and a molybdenum wire and a plurality of titanium wires are wound around the core. 2. A core made of multiple stranded tungsten wires,
A titanium evaporation wire characterized by comprising a molybdenum wire and a plurality of titanium wires wound around the core, and a guard member made of tungsten wire wound at a required interval around the outer periphery of the winding.