JPH05310478A - Method for joining carbon member - Google Patents

Abstract

PURPOSE:To obtain a sound composite of a carbon member with other members such as a metal by arranging a member to be joined through Ti or Cr and a metal brazing material on a joining surface of the carbon member and heating the resultant assembly. CONSTITUTION:A joining surface of a carbon member is printed or coated with pasty metallic powder composed of Ti or Cr and a metallic brazing material is then arranged on the metallic powder. A member to be joined is further arranged on the metallic brazing material. The resultant assembly is subsequently heated to a temperature above the melting point of the metallic brazing material in a nonoxidizing atmosphere to carry out the joining of the carbon member. The element (Ti or Cr), reactive with the carbon member and forming a carbide is heated in a state of close contact with the surface of the carbon member by arranging the element forming the carbide separately from the brazing material. Thereby, excessive reaction of the element forming the carbide with the brazing material or the joining member on the opposite side is suppressed. As a result, a reactional layer required for the joining is formed in the interface between the element forming the carbide and the brazing material to afford the objective sound joined body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial product using a carbon member such as a furnace wall for aerospace equipment and a nuclear fusion device or a high temperature gas reactor.

[0002]

2. Description of the Related Art Conventionally, a method of joining carbon members to each other or other materials is an active metal brazing material (USA Patent No. 2739375) in which Ti is added to an Ag-Cu alloy brazing material, Fe-Ni-.
Ti alloy wax (Japanese Patent No. 290561), Ti-Zr-Be
Alloy wax (Wel. J., Vol41, No.68), Ni
-Cr-Pd-Si alloy brazing material (JP-A-178399)
A carbon member is directly bonded to another member by a brazing material or foil such as Mo-Ni-Cr-Fe alloy brazing material (JP-A-62-21768) or V-Ti alloy foil (JP-A-2-23499). A method for doing so is disclosed. This brazing material contains an element that reacts with carbon to form a carbide near the interface.

On the other hand, as a method of brazing after forming a metallized layer on the surface of a carbon member, Japanese Patent Publication No. 3-54182 discloses that a eutectic alloy of Mo or W and Zr is arranged on the surface of graphite. Then, a method of heating in a non-oxidizing atmosphere is disclosed. However, this method requires heating at a high temperature of 1600 ° C., and there is a problem in workability.

[0004]

The conventional methods for directly joining a carbon member and a metal with a brazing material have the following problems.

In the method of directly joining with a brazing material containing a carbide-forming element, there are cases where the brazing material cannot be adhered to the carbon member when the carbon member has a complicated shape. In this case, before the brazing material reacts with the carbon member, the mating metal member to be joined reacts with the brazing material. For this reason, a phenomenon that a carbide forming element that reacts with the carbon member is insufficient, or a phenomenon that the composition of the brazing filler metal changes, does not form a carbide layer necessary for bonding at the bonding interface, or even if it does, a carbide layer is formed. May have a non-uniform thickness. Therefore, there arises a problem that a sound joined body cannot be obtained.

For example, in the case of directly joining a carbon member and a metal with a brazing material containing Ti, before Ti in the brazing material reacts with the carbon member to form a carbide layer necessary for joining at the joining interface, During the heating process, Ag or Cu of the brazing material composition diffuses to the metal side of the material to be joined, and the proportion of Ti in the brazing material composition changes. For this reason, a reaction layer having an appropriate thickness is not formed between the carbon member and the metal, and a sound bonding layer cannot be obtained.
This phenomenon occurs when the metal element that constitutes the brazing filler metal is included in the metal member side of the joining side, for example, Cu or A
This is remarkable when a metal member having a main composition of g is directly joined by a silver brazing alloy containing Ti.

On the other hand, when a carbon member and a metal member are directly joined by a brazing material containing Ti or Cr, the metal side of the joined member contains a metal having a high reactivity with Ti or Cr, such as Ni. The composition of the metal side, especially Ni, before Ti or Cr in the brazing material reacts with the carbon member.
Reacts with. For this reason, the amount of Ti or Cr that reacts with the carbon member is insufficient, a reaction layer having an appropriate thickness is not formed between the carbon member and the metal, and a sound bonding layer cannot be obtained. This phenomenon is caused by Ni on the other metal member side that is joined to the carbon member.
Is especially noticeable when included.

[0008] Further, when the metallized layer is previously formed on the joining surface of the carbon member and then the metal member is brazed, the same problem as described above occurs.

An object of the present invention is to provide a joining method for obtaining a sound composite of an isotropic carbon member or a carbon fiber reinforced carbon composite member and another member such as metal.

[0010]

According to the present invention, the carbide element contained in the brazing filler metal or the metallized layer disclosed above is separated from the brazing filler metal and placed in advance on the joining surface of the carbon member to form a carbide. Excessive reaction between the element and the brazing material or the brazing material containing the element and the metal can be suppressed. Therefore, even in the case of a carbon member having a complicated shape, a uniform carbide layer is formed at the bonding interface, and a sound bonded body can be obtained.

In order to achieve this object, the present invention provides a step of printing or applying a paste-like metal powder made of Ti or Cr on the bonding surface of a carbon member, a step of disposing a metal brazing material on the metal powder, It comprises a step of disposing a member to be joined to the carbon member on the metal brazing material, and a step of heating to a melting point of the brazing material or higher in a non-oxidizing atmosphere.

As a method of arranging the element that reacts with the carbon member to form a carbide separately from the brazing material, Ti or C is used.
The r powder is mixed with an organic solvent to form a paste, which is applied or printed on the surface of the carbon member to bring the above elements into close contact with the bonding surface of the carbon member. Next, a silver solder or a nickel solder is further placed thereon, and a metal member or a ceramic member is placed thereon, and the solder is heated to a temperature higher than the melting point of the brazing material. As a result, the carbide forming element is heated while being in close contact with the surface of the carbon member, and an excessive reaction between the carbide forming element and the brazing material or the mating joining member is suppressed. Therefore, a reaction layer having a uniform thickness is formed at the interface between the carbide forming element and the brazing material, and a sound bonded body is obtained.

[0013]

By disposing the element that reacts with the carbon member to form a carbide separately from the brazing material, the carbide forming element is heated while being in close contact with the surface of the carbon member. Therefore, an excessive reaction between the carbide forming element and the brazing material or the mating joining member is suppressed. Therefore, a reaction layer necessary for bonding is formed at the interface between the carbide forming element and the brazing material, and a sound bonded body is obtained. The elements that react with the carbon member to form carbides include Ti, Zr, Cr, Mo, Nb,
V is desirable. Among these, Ti and Cr are particularly desirable.
As a method for bringing the element into close contact with the surface of the carbon member, a method of mixing the element with an organic solvent to form a paste and applying or printing the paste on the surface of the carbon member is desirable. When Ti or Cr is uniformly mixed or alloyed in the brazing material, the amount of Ti or Cr in the brazing material is 1 to 30 wt%.
Is desirable.

[0014]

【Example】

<Example 1> One surface of isotropic graphite and carbon fiber-carbon composite material is mixed with Ti powder in an organic solvent to form a paste, which is applied to a thickness of 10 to 100 m. A 100 μm thick silver brazing foil made of a eutectic alloy is placed on this, and a copper block is placed thereon. This in a vacuum furnace at 850 ℃
By heating to, the graphite and the carbon fiber reinforced carbon composite member and the copper block are firmly bonded by TiC formed by the reaction of Ti and carbon.

As a result of a shear test of the joined body joined by this method, the addition amount of Ti in the silver solder is 1 to 30 ma.
In the case of ss%, the shear strength equivalent to that of the graphite member or the carbon fiber-carbon composite material was obtained.

Example 2 One surface of isotropic graphite and carbon fiber reinforced carbon composite material is coated with a paste in which Cr powder is mixed in an organic solvent. Ni-
A 100 μm thick Ni braze foil made of the alloy of B is placed on top of which a block of carbon steel is placed. 1 in a vacuum furnace
By heating to 000 ° C., the graphite / carbon fiber-carbon composite member and the copper block are firmly bonded. Also in this case, between the graphite and carbon fiber reinforced carbon composite material and the metallized layer,
It is strongly bonded by the Cr carbide formed by the reaction of Cr and carbon.

As a result of the shear test of this composite, the same shear strength as that of the isotropic graphite and the carbon fiber-carbon composite material was obtained.

Example 3 One side of a carbon fiber reinforced carbon composite member having a thickness of 20 mm and a size of 30 mm is processed into an arc shape having a radius of 10.5 mm. 20 pieces of paste-like Ti powder coated on the surface of the carbon composite material processed into the arc shape to a thickness of 20 μm are produced.

Next, an outer diameter of 20 mm and an inner diameter of 16 m were applied to the arc-shaped portion of the carbon composite member coated with the pasty Ti powder.
A copper pipe with a length of m and a length of 1000 mm, with a thickness of 100 μ
Place m silver brazing foil. Then, this is placed in a vacuum oven at 85
By heating to 0 ° C., the T formed between the carbon fiber-carbon composite member and the copper pipe by the reaction of Ti and carbon.
It is tightly bound by iC. By this method,
The joined joined body was used as a diverter wall for a nuclear fusion device. When the inner surface of the copper pipe of this diverter was cooled with cooling water having a flow rate of 1 m / s, irradiation of hydrogen ion beam with a heat flux of 20 MW / m ² was continuously performed, and the bonded body was sound. It should be noted that a Mo pipe or copper having the same shape as the above is used as Al.
Similar results were obtained in the case of a diverter in which copper alloys dispersion-strengthened with ₂ O ₃ were joined in the same manner.

[0020]

EFFECTS OF THE INVENTION According to the present invention, even in the case of a carbon member having a complicated shape, the carbide forming element is heated in a state in which it is in close contact with the joint surface of the carbon member. A carbide layer is formed. Therefore, a sound carbon joined body can be obtained. Further, since it is possible to easily join a large-sized carbon member having a complicated shape, it is possible to easily manufacture a large-scale structure such as a reactor wall for a fusion device.

Claims (2)

[Claims] 1. A step of printing or applying a paste-like metal powder made of Ti or Cr on the bonding surface of a carbon member, a step of disposing a metal brazing material on the metal powder, and a step of coating the metal brazing material on the metal brazing material. A method for joining carbon members, comprising the steps of arranging a joining member and then heating the melting point of the metal brazing material to a temperature above the melting point in a non-oxidizing atmosphere. 2. The amount of Ti or Cr in the brazing filler metal according to claim 1, when the Ti or Cr is uniformly mixed or alloyed with the metallic brazing filler metal, the amount is 1 to 30 w.
The joining method of the carbon member which is t%.