JP2000313677A - Joined product of carbon-based material with metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make both joint strength and a carbon-based material be highly strong by brazing/joining surfaces of a carbon-based material and a metal in a nonoxidizing atmosphere with palladium alloy powder or foil each containing silicon or titanium in a specific content based on the total weight of a brazing material. SOLUTION: This joined product is obtained by brazing/heat-treating surfaces of a carbon-based material and a metal with palladium alloy powder or foil each containing silicon or titanium in a content of 5-45 wt.% based on the total weight of a brazing material. The carbon-based material is obtained e.g. by formulating a carbide, boride and/or nitride of boron, silicon, zirconium, titanium, nickel or the like with carbon and by uniformly dispersing the composition in a carbon-based or graphite-based matrix. A cost in a joining process is remarkably reduced. The strength of the joined product is increased because the decomposition of compounds contained in the carbon-based material due to excess reaction is inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint between a carbon-based material and a metal.

[0002]

2. Description of the Related Art In general, a carbon-based material and a metal are joined by a mechanical joining method or a method using a brazing material. The mechanical joining method involves complicated processes such as processing of a carbon-based material and is expensive. When a brazing material is used, it is difficult to obtain a reaction layer having a uniform thickness due to the shape of the joining surface.

[0003] In order to obtain a uniform and high-strength joint using a brazing material, it is necessary to impregnate a carbon-based material or metal with a surface treatment such as impregnation, metallization, or CVD for the purpose of controlling the reaction. The process becomes complicated.

[0004] When brazing by heat treatment in a non-oxidizing atmosphere, the brazing material melts and penetrates into the carbon-based material while reacting with the carbon-based material. May drop. As a specific example, at the time of heat treatment, when a large amount of carbide generated by the reaction between the element contained in the brazing material and the carbon-based material is present in the reaction layer, a phenomenon occurs in which the reaction layer becomes brittle.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the joint portion strength and the carbon-based material can be reduced by a single heat treatment without performing a pre-treatment on the surface to be joined by the reaction between the brazing material and the element contained in the carbon-based material. Is to obtain a joined body with a metal which is in a high strength state.

[0006]

According to the present invention, there is provided a bonding structure of a carbon-based material and a metal, wherein an element selected from silicon and titanium is added between the surfaces to be bonded of the carbon-based material and the metal to the total weight of the brazing material. A palladium alloy powder or foil containing a weight ratio of 5 to 45% is subjected to brazing heat treatment, and reacts with carbon, boron, silicon, zirconium, and other elements contained in the carbon-based material to form a high-strength bonded structure. This is a feature and is a means for solving the conventional problem.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A brazing material made of a palladium alloy powder or a foil is placed at a joint between a carbon-based material and a metal, and heated to a temperature equal to or higher than the melting point, so that the brazing material component enters the carbon-based material. When the carbon-based material has open pores, the penetration of the molten brazing material into the carbon-based material is promoted. The brazing filler metal that has infiltrated into the carbon-based material reacts with carbon contained in the carbon-based material and other elements described above to form a reaction layer. The reaction layer formed by these phenomena forms a bond between the carbon-based material and the metal.

The carbon-based material in the present invention is a composite of carbon and ceramics, for example, boron, silicon carbide, boron carbide, zirconium boride, silicon carbide, zirconium, titanium, nickel, and other carbides, borides, nitrides, and the like. The compound is mixed with carbon and uniformly dispersed in a carbonaceous or graphitic matrix.

It is also preferable to provide a stress relaxation layer between the carbon-based material and the metal to relieve stress due to the difference in thermal expansion coefficient, if necessary. When the stress relieving layer is arranged, the stress relieving layer and the metal are joined by a nickel brazing filler metal, a palladium brazing filler metal or the like.

[0010] Palladium, which is a component of the brazing material, reacts with silicon contained in the carbon-based material to lower the melting point. This reaction is accelerated as the amount of silicon in the carbon-based material increases, and the penetration of the brazing filler metal component into the carbon-based material is facilitated.
Even if the brazing material is palladium alone, if silicon is contained in the carbon-based composite material, the bonding strength is secured by the reaction with the brazing material, but the silicon compound in the carbon-based material is decomposed by the reaction Therefore, when a destructive test is performed, the fracture occurs at this portion and the strength is lower than that of the carbon-based material itself.

When a palladium alloy powder or foil containing 5 to 45% by weight of an element selected from silicon and titanium with respect to the total weight of the brazing filler metal is used, the melting point of the brazing filler metal is lower than that of palladium alone and carbon is reduced. Infiltration into the system material becomes easy. Further, excessive reaction between the brazing filler metal component and the compound contained in the carbon-based material is suppressed, and the decomposition of the compound is suppressed. As a result, a joined body having high strength is obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to embodiments. Example 1 Palladium-on one surface of a carbon-based material
Silicon alloy powder or foil was placed. The powder was applied in the form of a paste by mixing with an organic solvent. Molybdenum was laminated thereon as a stress relaxation layer, and a nickel brazing material and a metal were further disposed. By heating this in a vacuum furnace to 1200 ° C. or higher, the carbon-based material and the metal were strongly bonded.

As a result of conducting a shear test on the joined body joined by this method, when the amount of silicon contained in the palladium brazing material is 5 to 45% by weight, it is stronger than the joined body using only the palladium brazing material. And a shear strength equivalent to that of a carbon-based material was obtained.

Example 2 A palladium-titanium alloy powder or foil was disposed on one surface of a carbon-based material. The powder was applied in the form of a paste by mixing with an organic solvent. Molybdenum was laminated thereon as a stress relaxation layer, and a nickel brazing material and a metal were further disposed. By heating this in a vacuum furnace to 1200 ° C. or higher, the carbon-based material and the metal were firmly joined.

As a result of conducting a shear test of the joined body joined by this method, when the amount of titanium contained in the palladium brazing material is 5 to 45% by weight, it is stronger than the joined body using only the palladium brazing material. And a shear strength equivalent to that of a carbon-based material was obtained.

[0016]

According to the present invention, the bonding structure between a carbon-based material and a metal according to the present invention is such that an element selected from silicon and titanium is applied to the bonding surface between the carbon-based material and the metal which are not subjected to surface treatment, etc. Since it is brazed with a palladium alloy powder or foil containing 5 to 45% by weight based on the weight, a processing step required for mechanical joining is unnecessary.
In addition, since the pretreatment of the surface of the carbon-based material and the metal for brazing is not required, the cost for the joining process can be significantly reduced, and the decomposition of the compound contained in the carbon-based material due to an excessive reaction is suppressed. Therefore, an excellent effect that the strength of the joined body was very high was obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C22C 5/04 C22C 5/04 // B23K 103: 18 F term (Reference) 4E067 AA01 AA16 AA18 AB01 AB06 DB02 DD01 4G026 BA13 BB21 BF22 BF24 BF38 BF42 BF44 BG02

Claims (2)

[Claims] 1. A palladium alloy powder or foil containing 5 to 45% by weight of an element selected from silicon and titanium with respect to the total weight of a brazing filler metal between surfaces to be bonded of a carbon-based material and a metal. A method for joining a carbon-based material and a metal, characterized by a structure obtained by attaching and joining. 2. The carbon-based material contains one or more of boron, silicon, zirconium, aluminum, molybdenum, chromium, nickel, cobalt, iron and titanium in addition to carbon, and is brazed to the metal in a non-oxidizing atmosphere. 2. The bonded body of a carbon-based material and a metal according to claim 1, wherein the bonded body is heat-treated.