JPH0881290A - Copper alloy-coated carbon material and its production and plasma counter material using copper alloy-coated carbon material - Google Patents

Abstract

PURPOSE: To improve the surface strength of a plasma counter surface, prevent the complication of its mass-production process, prevent the release from the surface, and improve thermal impact resistance by melt-coating holes or grooves formed on a carbon material with a copper alloy. CONSTITUTION: The foil or plate-like article of a copper alloy comprising 98-60wt.% of copper and 2-40wt.% of titanium is arranged on circular grooves (c) 3, oval or polygonal holes or U-shaped grooves (a) 1 or V-shaped grooves 2 having a depth of >=0.5mm from the surface and a distance of >=2.0mm to the opposite side surface and formed in a carbon material such as an isotropic or anisotropic artificial graphite material or carbon/carbon composite material. A paste produced by adding an organic binder, a solvent, etc., to the powdery mixture of the above composition is coated on the grooves. The foil, plate-like article or the coating layer to the carbon material is heated at 900-1600 deg.C in vacuo or in an inert gas atmosphere to obtain the copper alloy-coated carbon material whose holes or grooves are covered with the copper alloy. The copper alloy-coated carbon material is subjected to a metallurgic adhesion to a cooling material comprising the metal or alloy of copper, molybdenum or tungsten on the surface of the copper alloy to obtain the plasma counter material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon material having a hole or groove processed surface coated with a copper alloy, particularly a copper alloy-coated carbon material suitable for a plasma facing material of a fusion reactor and a method for producing the same. And a plasma facing material using a copper alloy coating material.

[0002]

2. Description of the Related Art Carbon materials have excellent heat resistance and chemical stability and are therefore extremely useful as various members used at high temperatures. The metallurgically bonded member of carbon material and metal is used for the plasma facing material of the fusion device, the semiconductor manufacturing device, etc. for the purpose of utilizing this excellent feature, improving cooling efficiency, reinforcing mechanical strength, etc. Is required. As a method of metallurgically joining the carbon material and the metal, brazing with a brazing material between the carbon material and the metal is generally performed.

However, in the case of mere brazing, there are problems that the carbon material and the metal are easily separated from each other due to the difference in thermal expansion coefficient, and the pores are present on the surface of the carbon material, so that the bonding strength and reliability are low. is there. In addition, it is necessary to add an active metal such as titanium or chromium to the brazing filler metal to form a carbide layer of the active metal at the interface between the carbon material and the metal. The thickness of this metal carbide layer should be controlled uniformly. Since it is difficult to do so, there was a problem in the reliability of the bonding strength.

As a method for solving such a problem, for example, in Japanese Unexamined Patent Publication No. 62-130383, a high melting point, low sputtering rate material (graphite etc.) and a high thermal conductivity metal (copper etc.) are used. A method is proposed in which the content is integrated under pressure so that the content is higher than that of the plasma surface, and the difference in coefficient of thermal expansion is relaxed to join the cooling pipe. In addition, JP-A-5-18
In the 6276 publication, a carbon fiber reinforced carbon composite material (C / C composite material) having a dense surface and a sparse inside is made of copper or the like by HIP (hot isostatic press (hot isostatic press)). We have proposed a bonding material that is impregnated with a high thermal conductivity material and has a copper composition with gradient functionality. Further, Japanese Patent Laid-Open No. 63-310778 proposes a method of metalizing a bonding surface of a carbon material and then bonding the metal material to a metal base material via a stress relaxation layer such as nickel.

[0005]

In order to effectively utilize the heat resistance and chemical stability of the carbon material, it is necessary that the surface opposite to the joining surface contains no metal. In the method disclosed in Japanese Unexamined Patent Publication No. 62-130383, graphite and metal are pressure-integrated, so that when only the surface facing the plasma is made of graphite, the graphite particles are weakly bonded to each other, so that a strong surface is obtained. Cannot be formed.

Further, in the method disclosed in Japanese Patent Laid-Open No. 5-186276, the depth of penetration of copper by pressure impregnation is C / C.
It depends on the pore distribution of the composite. Therefore, strict control of the pore distribution is necessary in order to make the plasma facing surface contain no metal at all and to make the copper content of the bonding surface sufficient. Mass production is considered to be difficult.

Further, in the method disclosed in Japanese Patent Laid-Open No. 63-310778, since the joining is performed via the stress relaxation layer, the joining is performed on two sides, which complicates the joining process. Further, since the metallized layer and the carbon material have different coefficients of thermal expansion, thermal stress may cause peeling from the interface.

[0008]

The present invention provides a hole or groove formed in a carbon material, the hole or groove having a depth of 0.5 mm or more,
Copper alloy-coated carbon material obtained by melting and coating a copper alloy at a temperature higher than 900 ° C. and lower than 1600 ° C. and a hole formed in the carbon material with a mixture of copper powder and titanium powder to be a copper alloy or a copper alloy after melting. Alternatively, the method for producing a copper alloy-coated carbon material in which a copper alloy is coated by heating and melting in a vacuum or an inert gas atmosphere after placing on a groove, and cooling the above copper alloy-coated carbon material on the surface of the copper alloy The present invention relates to a plasma facing material of a fusion device which is metallurgically bonded to a body.

The carbon material used in the present invention is a generally known isotropic or anisotropic artificial graphite material, C / C.
Although it is a composite material and the like, there is no particular limitation, but since the copper alloy enters into the open pores of the carbon material in addition to the holes and grooves formed in the carbon material to improve the adhesive strength, an open porosity of 3% or more is required. It is preferable to use a carbon material having the same.

The depth, shape and arrangement of the holes or grooves on the surface of the carbon material have a great influence on the adhesion strength, the improvement of the thermal conductivity and the relaxation of the difference in the coefficient of thermal expansion. The depth of the hole or groove from the surface is set to 0.5 mm or more, and if it is less than 0.5 mm, these effects cannot be obtained so much. The depth of the hole or groove is more preferable if the depth is in the range of 1.0 to 2.0 mm because the effect is large, and if the depth is 2.0 mm or more, these characteristics are significantly improved. Particularly preferred. In addition,
It is preferable that the depth of the hole or groove is at most the depth that does not exude to the opposite surface when coated with the copper alloy. More preferably, the distance between the position where the copper alloy has penetrated and the opposite side surface is 2.0 mm or more. In addition,
The penetration depth of the copper alloy in the present invention refers to the depth at which the presence of the copper alloy is confirmed by a technique such as a soft X-ray transmission photograph and an EPMA (electron probe micro analysis) analysis of a cross section.

The shape and arrangement of the holes or grooves are not particularly limited, and the shape of the holes may be any of circle, ellipse, triangle, quadrangle, polygon, etc. The shape of the groove is a round bottom groove (U-shaped etc.), Either a square bottom groove or a V-shape may be used. The holes or grooves may be arranged in parallel in one direction, in a grid pattern, in multiple directions, etc. Also, not only straight lines but also polygonal lines, circles, spirals, and curved lines It may be arranged such as. As the number of holes or grooves increases, the effect of improving the thermal conductivity increases, but if the number of holes or grooves increases too much, the effects of improving the adhesive strength and relaxing the difference in thermal expansion coefficient decrease. Therefore, in order to improve the effect in a well-balanced manner, the area ratio of the holes or grooves is preferably in the range of 20 to 80% with respect to the carbon material.

The copper alloy in the present invention means an alloy composed of copper and titanium. Copper is used because it has high thermal conductivity, can be melted at a relatively low temperature, and is low in price. At the same time, copper is generally used for the cooling body, so it can be easily joined to the cooling body. There is also an advantage. However, even if the simple substance of copper is melted, it does not wet with the carbon material, so it is necessary to add an active metal that improves wettability. Therefore, in the present invention, titanium that reacts with the carbon material to form a carbide is used as the additive metal.

The weight composition of the copper alloy is 98-60% by weight of copper and 2-40% by weight of titanium in terms of the effect of improving the wettability, the ease of infiltration of the alloy, the thermal conductivity of copper, the thermal shock resistance and the like. It is preferably in the range of. A more preferable composition range is 96 to 70% by weight of copper and 4 to 30% by weight of titanium.

The coating of the copper alloy with the carbon material is carried out by arranging a foil or plate-shaped copper alloy having the above-mentioned composition on the carbon material and heating or melting it, or mixing the copper alloy after the melting so as to have the above-mentioned composition. A mixture of copper powder and titanium powder to be placed on the carbon material is heated and melted. In the method using the mixture, the form of the mixture may simply be a mixed powder of copper powder and titanium powder, but an organic binder, a solvent or the like is added to these mixed powders to form a paste, which is applied onto a carbon material. It is preferable to use a method of heating and melting after that, because more uniform coating is possible.

In the method using a paste, a known thermosetting resin, thermoplastic resin, or the like is used as the organic binder, and there is no particular limitation, but the higher the carbonization rate, the higher the copper after heat treatment. Since a large amount of carbon remains in the alloy, it is preferable to use a binder having a low carbonization rate such as acrylic resin, epoxy resin, polyvinyl alcohol, and methyl cellulose.

The solvent preferably has a boiling point range of about 100 to 200 ° C. from the stability and workability of the paste, and an organic solvent such as ethylene glycol or butanol or water is selected in consideration of the compatibility with the organic binder. It is preferable to use.

The heating temperature (melting temperature) for coating the carbon material by placing a copper alloy or a mixture of copper powder and titanium powder on the carbon material, heating and melting, exceeds 900 ° C.,
The temperature is lower than 1600 ° C, and the temperature lower than 900 ° C does not melt the copper alloy. Therefore, 950 ° C or higher is preferable,
More preferably, it is 1050 ° C or higher. Meanwhile, 1600 ° C
If it is above, the composition may change due to evaporation.

Since copper, titanium and carbon materials easily react with oxygen, it is necessary that the atmosphere for heating and melting is free of oxygen. Titanium also reacts with nitrogen. For this reason, heating and melting are performed in vacuum or in an inert gas atmosphere. When heating and melting in a vacuum, the degree of vacuum is preferably at least higher than ¹ Pa, and more preferably higher than 1 × 10 ⁻¹ Pa, in order to prevent oxidation.

When the atmosphere is an inert gas, it is preferable to use a high-purity gas having a low oxygen content, for example, a gas having oxygen impurities of 20 ppm or less. However,
Since nitrogen gas reacts with titanium, it is necessary to use an inert gas other than nitrogen gas, such as argon and helium.

A copper alloy-coated carbon material in which a hole or groove formed in the carbon material is coated with a copper alloy is metallurgically bonded to the cooling body on the copper alloy surface, thereby providing a nucleus having high bonding strength and reliability. It can be the plasma facing material of the fusion device.

In the present invention, the cooling body means a metal such as copper, molybdenum, tungsten, iron or titanium or an alloy thereof, which has a function of cooling the copper alloy infiltrated carbon material bonded to the surface. Say. The structure preferably has a structure capable of cooling with a liquid such as gas or water in order to enhance cooling efficiency, and for example, a through hole for circulating a refrigerant in a block-shaped or plate-shaped cooling body is provided. It is preferable to use a structure provided, a structure in which a pipe through which a refrigerant flows is joined to a cooling body, or the like.

The metallurgical joining means joining by brazing, diffusion joining and the like, and in the present invention, joining by brazing, which enables joining at a relatively low temperature, is preferable. For brazing, Ag, Ag-Cu, Pd, Pd-Ag, Pd-
Ag-Cu, Ni, Mn, Ni-Cu, Cu-Mn, A
A brazing material such as g-Cu-In or Ag-Cu-Sn is used. In addition, Ti, Zr, Hf, Be,
It is preferable to use a material to which an active metal such as W, V, Nb or Ta is added, since the wettability of the brazing material is improved. The brazing conditions are appropriately selected according to the brazing material used.

[0023]

The function of the copper alloy-coated carbon material according to the present invention is that the surface of the carbon material is coated with the copper alloy and the copper alloy penetrates into the holes or grooves formed in the carbon material. In addition, the structure is such that the copper alloy grows roots in the carbon material. This structure improves the adhesive strength. Also,
With such a structure, thermal stress is relieved and thermal conductivity is also improved, so that thermal shock resistance is excellent. Since the joining with the metal cooling body is joining between the metal surfaces, the joining strength and reliability are higher than those of the conventional carbon-metal joining.

[0024]

EXAMPLES Examples of the present invention will be described below. Examples 1 to 9 and Comparative Examples 1 to 6 C / C composite material (manufactured by Hitachi Chemical Co., Ltd., trade name PCC-2S, open porosity 8%) processed into dimensions of 25 × 25 × 25 mm was used as a base material. Further, the mixed powder of copper powder (Nikko CCS Chemical, electrolytic copper powder) and titanium powder (Wako Pure Chemical Industries, average particle size 250 μm), which become a copper alloy after melting, is mixed in the mixing ratio shown in Table 1. It was used. For hole or groove processing,
U-shaped groove (width 1.5mm) 1 as shown in Fig. 1 (a)
Is processed into type A, and as shown in FIG. 1 (b), a V-shaped groove (width 1.5 mm) 2 is processed into type B
Further, as shown in FIG. 1 (c), a hole having a circular hole (diameter of 1.5 mm) 3 was machined as a type C.

Next, to 60% by weight of the above mixed powder, 30% by weight of alkyd resin (Hitachi Chemical Co., Ltd., trade name V901) and 10% by weight of butanol (Wako Pure Chemical Industries, reagent first grade) were added and mixed to form a paste. After arranging (applying) the converted products on the substrate, respectively, in a vacuum atmosphere of 1 × 10 ⁻¹ Pa,
Each was heated to the temperature shown in Table 1 and held for 1 hour to obtain a copper alloy-coated carbon material.

A copper block was silver-brazed to the obtained copper alloy-coated carbon material, and the joint strength was determined by a tensile test.
The results are shown in Table 1. However, in the above test, in Comparative Example 5, the bonding strength was measured for a copper block which was not brazed with a copper alloy and was brazed with silver, and in Comparative Example 6, the strength of a single substrate was measured.

Further, a thermal shock test of irradiating an electron beam in a vacuum on the typical copper alloy-coated carbon materials obtained in the above-mentioned Examples and Comparative Examples and the carbon material not coated with the copper alloy of Comparative Example 5 I went. The irradiation energy of the electron beam was (1) 10 MW / m ² and (2) 15 MW / m ² , the irradiation time was 1 second, and the irradiation was performed up to 5 times. Table 3 shows the number of irradiations until peeling after each irradiation.

[0028]

[Table 1]

Examples 10 to 16 and Comparative Examples 7 to 10 Isotropic graphite material processed to a size of 25 × 25 × 25 mm (Hitachi Chemical Co., Ltd., trade name PD-600, open porosity 12%).
Is used as a base material, and a mixed powder of copper powder and titanium powder that becomes a copper alloy after melting (all using the same powder as that used in Examples 1 to 9) has a mixing ratio shown in Table 2. A mixture was used. Grooving is performed by machining three U-shaped grooves (width 1 mm) as shown in FIG.
As shown in Fig. 2 (b), 6 pieces of U-shaped groove (width 1mm) were machined to form type E and U-shaped groove (width 1mm) as shown in Fig. 2 (c). , Type 10 was processed laterally.

Next, 20% by weight of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, degree of polymerization 1500) and 15% by weight of water were added to 65% by weight of the above mixed powder and mixed to form a paste. After the arrangement (coating), each was heated to a temperature shown in Table 2 in an argon gas atmosphere (oxygen and nitrogen impurities were 10 ppm or less) and held for 1 hour to obtain a copper alloy-coated carbon material.

A copper block was silver brazed to the obtained copper alloy-coated carbon material, and the bonding strength was determined by the same method as in Examples 1-9. The results are shown in Table 2. However, in the above test, in Comparative Example 9, the joint strength was measured for a copper block which was not brazed with a copper alloy and was brazed with silver, and in Comparative Example 10, the strength of a single substrate was measured.

Further, the typical copper alloy-coated carbon materials obtained in the above-mentioned Examples and Comparative Examples and the carbon material of Comparative Example 9 not coated with the copper alloy were subjected to a thermal shock test of irradiating them with an electron beam in a vacuum. I went. The irradiation energy of the electron beam was (1) 5 MW / m ² and (2) 10 MW / m ² (only Example 13 was added up to 15 MW / m ² ), irradiation time was 1 second, and irradiation was performed up to 5 times. It was Table 3 shows the number of irradiations until peeling after each irradiation.

[0033]

[Table 2]

[0034]

[Table 3]

As shown in Table 1, Table 2 and Table 3, the copper alloy-coated carbon materials according to the examples of the present invention were compared with the copper alloy-coated carbon materials according to the comparative examples and the carbon materials without copper alloy coating. It is shown that the bonding strength and thermal shock resistance are excellent.

[0036]

According to the present invention, it is possible to provide a copper alloy-coated carbon material having excellent bonding strength with metal and thermal shock resistance, a method for producing the same, and a plasma facing material using the copper alloy-coated carbon material. it can.

[Brief description of drawings]

1A, 1B and 1C are perspective views showing a state in which a groove and a hole are formed in a carbon material according to an embodiment of the present invention.

2 (a), (b) and (c) are perspective views showing a state in which a carbon material according to another embodiment of the present invention is grooved.

[Explanation of symbols]

 1 U-shaped groove 2 V-shaped groove 3 Circular hole

Claims (3)

[Claims] 1. A hole or groove formed in a carbon material and having a depth of 0.5 mm or more exceeds 900 ° C. and 1600.
A copper alloy-coated carbon material obtained by melting and coating a copper alloy at a temperature of less than ℃. 2. A copper alloy or a mixture of copper powder and titanium powder to be a copper alloy after melting is placed on a hole or groove formed in a carbon material, and then heated and melted in a vacuum or in an inert gas atmosphere. A method for producing a copper alloy-coated carbon material, which comprises coating a copper alloy with a copper alloy. 3. The copper alloy-coated carbon material according to claim 1,
A plasma facing material for a fusion device that is metallurgically bonded to a cooling body on the surface of a copper alloy.