JPH0288470A - Method for joining silicon carbide material - Google Patents

Abstract

PURPOSE:To improve joining strength and reliability of the joining part of silicon carbide material by chemically treating the face to be joined of silicon carbide material and forming open pores a bonding agent to penetrate in and thereafter joining material to be joined. CONSTITUTION:The face to be joined of silicon carbide material obtained by a reaction sintering method is chemically treated by strong alkaline chemicals or strong acidic chemicals. The components which are interposed between silicon carbide grains in the vicinity of the face to be joined of the above-mentioned silicon carbide material and can be dissolved out by the chemicals are removed by this treatment. In such a way, the open pores having prescribed depth are formed on the face to be joined of silicon carbide material and a joining agent holdable in a fluidized state is allowed to penetrate into the open pores and thereafter material to be joined is joined to this joining face. The open pores having a complex shape are formed on the surface layer part of silicon carbide material by performing joining in the above method. The bonding agent or the material to be joined is introduced into the open pores and thereby both silicon carbide material and the material to be joined can be tightly joined by so-called anchoring action.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for joining silicon carbide, and more specifically, to a method for joining silicon carbide with an organic material, an inorganic material, or a metal material that is easy to machine, and silicon carbide that has excellent properties. This invention relates to a method of joining with a joint surface having stable strength and high reliability.

[Conventional technology]

In general, silicon carbide is a very chemically stable material and is also a dense material, so it has excellent bending strength, fracture toughness, hardness, heat shock resistance, etc., and has a low coefficient of thermal expansion, making it desirable as a structural material. It has characteristics.

As described above, silicon carbide is chemically stable and dense, so it has disadvantages in terms of machining, etc. Therefore, it cannot be used as an organic material, an inorganic material, or a metal material that is easy to machine. They are joined together to form structural materials suitable for each purpose.

When joining silicon carbide and other materials as described above, +11 A method of roughening the joining surface of silicon carbide by machining or sanding before sintering the silicon carbide, ( 2) After sintering silicon carbide, a method of roughening the hard surface using short blasting, diamond filing, etc. is adopted.

[Problem to be solved by the invention]

However, in the +11 and (2) methods described above, when the roughened area is enlarged as shown in Figure 5, the uneven parts have a relatively smooth shape. The material to be welded has entered the joint, making it impossible to ensure a sufficiently strong welding condition.

In addition, in the method of mechanically roughening the joint surface of silicon carbide,
It is difficult to uniformly roughen the entire joint surface.

For this reason, the joint strength and reliability of the joint between silicon carbide and other materials have not been sufficient.

An object of the present invention is to solve the problems of the prior art described above, and to improve the bonding strength and reliability of silicon carbide and other materials when they are bonded together. The object of the present invention is to provide a method for joining materials.

[Means to solve the problem]

In order to achieve the above-mentioned object, the first aspect of the present invention is to chemically treat the surface to be joined of a silicon carbide material obtained by a reaction sintering method with a strong alkaline agent or a strong acidic agent, and to Remove components that can be eluted by the drug that are present between silicon carbide grains near the surface of the silicon carbide material to be joined, and form open pores with a predetermined depth from the surface of the silicon carbide material to be joined. The second aspect of the present invention is that after a bonding material that can be maintained in a fluid state is infiltrated into the open pores, a material to be bonded is bonded to the surface of the bonded material. It is characterized by permeating or diffusing materials.

[Effect]

When a silicon carbide material is chemically treated with a strong alkaline agent or a strong acidic agent, components such as unreacted metallic silicon present in the silicon carbide material are eluted, creating complex-shaped open pores in the surface layer of the silicon carbide material. is formed.

When a bonding material made of a flowable material is infiltrated into the surface layer where open pores are formed by means such as coating, this bonding material enters into the open pores and interacts with the silicon carbide material due to the so-called anchoring action. Strongly bonded.

Therefore, a material having high chemical affinity with the bonding material can be selected as the material to be bonded, and the bonding strength between the two can be improved.

Similarly, when the material to be joined permeates or diffuses into the open pores, the material to be joined is firmly joined to the silicon carbide material due to the anchoring action.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic diagram of the structure of a silicon carbide material applied to the joining method of the present invention.

This silicon carbide material is formed by a reaction sintering method,
It has a structure in which unreacted metal silicon 2 and carbon particles are mixed in the gaps between granular silicon carbide 1.

The surfaces to be joined of silicon carbide materials made of such mm are chemically treated with strong alkaline chemicals (e.g., sodium hydroxide, potassium hydroxide, etc.) or strong acid chemicals (hydrofluoric acid, hydrofluoric acid + nitric acid). to be processed.

FIG. 2 shows a schematic diagram of the structure of the surface to be joined of the silicon carbide material after this chemical treatment.

As is clear from Figure 2, the silicon carbide material surface (surface layer)
Nearby, the metal silicon 2 is eluted and removed by a strong alkaline or acidic chemical, and open pores 4 having a complicated communicating hole shape are formed in the surface layer.

In this case, the size, shape, etc. of the open pores 4 formed in the surface layer portion are adjusted by the composition of the silicon carbide material and manufacturing conditions.

In addition, the depth of the open pores 4 formed in the surface layer is adjusted depending on the chemical treatment conditions (for example, the concentration of the chemical, the temperature, the immersion time of the silicon carbide material in the chemical, etc.), and the required depth can do.

After the complex-shaped open pores 4 are formed in the surface layer of the silicon carbide material in this way, the surface layer is bonded to an easily machinable organic material, an inorganic material, or a bonding material 5. Other materials (materials to be joined 6) such as metal materials are joined.

When bonding the material 6 to be bonded to the silicon carbide material via the bonding material 5, the bonding material 5 penetrates into the open pores 4 in a heated and molten state, or in a liquid state, as shown in FIG. In the figure, the layer is filled in the region indicated by the layer thickness T.

In this case, the bonding material 5 can be selected from a material that has excellent chemical affinity with the materials 6 to be bonded.

The bonding material 5 can be physically strongly bonded to the silicon carbide material by a so-called anchoring effect, and the bonding material 5 and the material to be bonded 6 can be chemically strongly bonded.

Note that the surface layer portion of the bonding material 5 may be appropriately roughened to chemically and physically bond the bonding surfaces of the bonding material 5 and the material to be bonded 6.

When joining the material to be joined 6 directly to a silicon carbide material, the material to be joined 6, which can flow under pressure and heat, is placed on the surface layer where the open holes 4 are formed, and then the material to be joined 6, which can flow under pressure and heat, is placed on the surface layer in which the open holes 4 are formed, and then the material to be joined is placed on the surface layer in which the open holes 4 are formed, and the material is heated under pressure, etc. The fluidized material 6 to be joined is diffused into the open hole 4.

In this method, as shown in FIG. 4, the material to be joined 6 directly diffuses and permeates into the open pores 4, so that the two are firmly joined by a so-called anchoring effect.

〔Effect of the invention〕

As described above, according to the present invention, components such as unreacted metal silicon interposed in the granular silicon carbide gaps in the silicon carbide material are eluted and removed by a strong alkaline agent or a strong acid agent, and the silicon carbide material is Complex-shaped open pores are formed in the surface layer, and the joining material or the material to be joined enters into these open pores, and the silicon carbide material and the material to be joined can be firmly joined by a so-called anchoring effect. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the structure of the silicon carbide material applied to the present invention, FIG. 2 is a schematic diagram of the structure of the surface layer when the silicon carbide material is chemically treated with a strong alkaline agent or a strong acid agent, and FIG. Figure 3 is a schematic diagram of the cross-sectional structure of a joint when a material to be joined is joined to a silicon carbide material via a bonding material, and Figure 4 is a diagram of a joint when a material to be joined is joined directly to a silicon carbide material. Fig. 5 is a schematic cross-sectional view of the weave of a joint by a conventional joining method. l...Silicon carbide 2...Metal silicon 3...Carbon grains 4...Open pores 5...Binding material 6...・・To be joined material diagram 3rgJ diagram 4

Claims (2)

[Claims] (1) The surface of the silicon carbide material obtained by the reaction sintering method is chemically treated with a strong alkaline agent or a strong acidic agent, and the silicon carbide grains near the surface of the silicon carbide material are Remove the intervening components that can be eluted by the drug, form open pores with a predetermined depth from the surface of the silicon carbide material to be joined, and infiltrate a bonding material that can be maintained in a fluid state into the open pores. 1. A method for joining silicon carbide materials, comprising: bonding a material to be joined to the surface of the material to be joined. (2) The surface of the silicon carbide material obtained by the reaction sintering method is chemically treated with a strong alkaline agent or a strong acidic agent, and the silicon carbide grains near the surface of the silicon carbide material are The intervening components that can be eluted by the drug are removed to form open pores with a predetermined depth from the surface of the silicon carbide material to be joined, and the material to be joined that can be held in a fluid state is placed in the open pores. A method for joining silicon carbide materials characterized by penetration or diffusion.