JP2515927Y2 - Bonding structure of ceramic members and metal members - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a joining structure between a ceramic member and a metal member, which are required to have high temperature durability.

[Prior Art] In recent years, mechanical parts that are used under high load and high temperature atmosphere in various industrial machinery have various types of ceramic members that are excellent in heat resistance, corrosion resistance and wear resistance, and have high strength and light weight. It started to come.

However, since the ceramic member has a difficulty in workability and the toughness of ceramics is poor, the part where high temperature acts is composed of a ceramic member having excellent heat resistance, corrosion resistance, and wear resistance and a small specific gravity, and a high load. The part that acts on is composed of a metal member with high strength and excellent workability, etc.
Attention has been paid to a composite structure in which a ceramic member and a metal member are combined, and various joining structures of the ceramic member and the metal member have been studied and proposed.

Conventionally, as a joining structure of a ceramic member and a metal member, as shown in FIG. 4, the joining portion of the ceramic member 11 is polished to form a flat surface or a convex portion, and the ceramic member is formed at one end of the metal member 14. Iron-nickel alloy having a similar thermal expansion coefficient or the intermediate member 19 made of a heat-resistant alloy such as Incoloy having a low coefficient of thermal expansion, the ceramic member 11 is closely adhered or pressed into the flat surface or the concave portion, and diffusion bonding or brazing is performed. A joint structure of a composite structure joined by shrink fitting has been proposed (see JP-A-63-297279).

[Problems to be solved by the invention] However, in recent years, the demand for a composite structure having a joint portion that can be used at high temperatures and has excellent durability has been increasing year by year, and conventional intermediate members have been It was difficult to satisfy the above requirements for a composite structure joined by diffusion bonding, brazing, shrink fitting, etc.

That is, in a conventional composite structure in which a diffusion bonding method, a brazing using a brazing material, or a shrink fitting by heating at a high temperature is used to bond the metal member after the bonding, the diffusion bonding method, the brazing or the brazing method is used. By being heated to a high temperature at the time of fitting, it becomes an annealed state at room temperature, resulting in insufficient strength as a metal member of the composite structure. Therefore, it is necessary to heat-treat the metal member again after joining to recover the strength, but cracks may occur in the ceramic member due to increase in internal stress and shrinkage fitting force due to thermal strain on the intermediate member generated by the heat treatment. However, there is a problem that the intermediate member itself is broken or the joint is broken.

[Means for Solving the Problems] The joining structure of the ceramic member and the metal member of the present invention is
The first and second buffer layers brazed to the end surface of the ceramic member are fitted so as to cover from the end portion of the ceramic member to the end portion of the metal member arranged with a slight gap from the end surface of the second buffer layer. It is characterized in that the inserted metal sleeve is joined and integrated with a metal member arranged so as to have a slight gap with the end face of the second buffer layer.

As the first buffer layer, a Ni-Ti alloy or a low Young's modulus alloy such as Cu is desirable.

Further, as the second buffer layer, a metal containing W as a main component such as WC having a low coefficient of thermal expansion is preferable.

Further, as the metal sleeve, a heat-resistant alloy having a thermal expansion coefficient close to that of ceramics is desirable, and a heat-resistant alloy having a thermal expansion coefficient of less than 9 × 10 ⁻⁶ / ° C. at 40 ° C. to 1000 ° C. is particularly preferable.

On the other hand, for the joining of the metal sleeve and the metal member, electron beam welding, laser welding, or the like can be suitably adopted in addition to brazing.

[Operation] In the bonding structure of the ceramic member and the metal member as described above, the ceramic member end face and the first buffer layer are brazed, and the second buffer layer is further brazed to the first buffer layer,
The first and second buffer layers and the metal sleeve are joined,
Since the metal sleeve and the metal member are joined and integrated as a composite structure, the metal sleeve only holds the ceramic member via the brazing material, and the metal sleeve and the second buffer Since the coefficient of thermal expansion is similar to that of the layer, it alleviates thermal strain on the metal sleeve due to heat treatment of the metal member, and further alleviates the effect of thermal strain on the metal sleeve on the ceramic member, and Since the second buffer layer and the metal member have a slight gap, they act to reduce heat conduction from the ceramic member to the metal member.

[Examples] Hereinafter, the present invention will be described in detail.

FIG. 1 is a partial cross-sectional view of an embodiment showing a joining structure of a ceramic member and a metal member according to the present invention.

In FIG. 1, 1 is a ceramic member, 2 and 3 are first buffer layer and second buffer layer, respectively, 4 is a metal member, 5
Indicates a metal sleeve, and the ceramic member 1 is brazed to the first buffer layer 2 and the second buffer layer 3 by the brazing material 6 and the end surface of the second buffer layer 3 has a slight gap G. The metal member 4 thus arranged is brazed and integrated with the first buffer layer 2 and the second buffer layer 3 by the brazing material 6 on the inner peripheral surface of the metal sleeve 5 fitted on the outer periphery thereof. Has been done.

Next, the joint structure of the ceramic member and the metal member according to the present invention will be specifically described in detail by taking a composite structure of the evaluation ceramic member and the metal member as an example.

A silicon nitride sintered body containing silicon nitride (Si ₃ N ₄ ) as a main component, yttria (Y ₂ O ₃ ) and tungsten oxide (WO ₃ ) as a sintering aid, and sintered in a nitrogen atmosphere was used. 170
The end face was ground by a universal grinder using a diamond grindstone corresponding to the No. standard, and a cylindrical ceramic member 1 having a diameter of 11 mm and a length of 70 mm was obtained.

On the other hand, a heat-resistant steel material equivalent to the SUH600 standard is used as a metal material, and a cylindrical body having a diameter of 11 mm and a length of 150 mm is machined to form a metal member 4 with 38% Ni, 15% Co corresponding to Incoloy 909, and the balance
Using a nickel-based alloy material consisting of e, outer diameter 16 mm, length 1
3 mm, the inner diameter has a clearance of 10 to 1 from the outer diameter of the metal member 4.
A metal sleeve 5 was obtained by cutting while matching the actual product so as to have a diameter of 00 μm.

Also, a wire rod made of BAg-8 standard silver braze having a diameter of 0.8 mm is formed into a ring shape having an inner diameter of 11 mm, and a 0.2 mm thick foil member made of the same silver braze is cut out to have a diameter of 11 mm, and Diameter 11 mm as the first buffer layer and the second buffer layer
Prepare the materials shown in Table 1 of.

First, the ceramic member 1, the first and second buffer layer materials 2 and 3, the metal member 4, the metal sleeve 5, and the silver brazing material are washed with a degreasing agent or the like.

Then, after depositing a metallized metal layer containing silver (Ag) as a main component on the end surface of the ceramic member 1, a thickness of 0.2 m
1 m silver brazing foil, first buffer layer 2 with the thickness shown in Table 1
Then, four silver brazing foils having a thickness of 0.2 mm and then the second buffer layer 3 having the thickness shown in Table 1 are sequentially laminated, and the metal sleeve 5 is fitted into them.

Next, a mixture of graphite powder and an organic solvent is applied to the end face of either the second buffer layer 3 or the metal member 4 to a film thickness of 20 to 100 μm.
After applying about m, the metal member 4 is fitted into the metal sleeve 5 until it comes into contact with the end surface of the second buffer layer, and three silver brazing rings are placed near the boundary between the metal member 4 and the metal sleeve 5. Place them, fix them with a graphite jig, and then in a vacuum furnace 850-9
Heat treatment at a temperature of 50 ° C and braze.

The depth at which the metal member 4 was fitted into the metal sleeve 5 was 6 mm, which showed the highest bending strength as a result of preliminary tests in which various settings were made from 1 to 12 mm.

Regarding the composite structure of the ceramic member and the metal member thus obtained, 4 parts of the metal member of the composite structure is gripped by a chuck of a tester in a high temperature atmosphere of 550 ° C., and the tip of the ceramic member 1 is projected upward. The pressure was further increased, the load at break was measured, and the high temperature cantilever bending strength was determined and evaluated.

A composite structure without the first buffer layer and a composite structure without the first and second buffer layers were used as comparative examples.

 The above results are shown in Table 1.

As is clear from Table 1, the thickness of the second buffer layer is 1.0m.
In the sample Nos. 1, 4, and 7 of m, the second buffer layer peeled off from the metal sleeve and broke, and the high temperature cantilever bending strength was 16
It is as low as kg / mm ^2, which is not much different from the comparative example. On the other hand, the sample numbers 2, 3, 5, 6 in which the thickness of the second buffer layer is 2.0 mm or more,
In Nos. 8 and 9, fracture occurred at the brazing surface between the ceramic member and the first buffer layer, and the high temperature cantilever bending strength was also extremely large at 21 kg / mm ² or more, so the thickness of the second buffer layer was 2.0. mm or more is desirable.

FIG. 2 shows an example in which the joining structure of a ceramic member and a metal member according to the present invention is applied to a radial type rotor such as a turbocharger or a gas turbine. The rotor is a ceramic member 1 made of a silicon nitride sintered material. The first buffer layer 2, the second buffer layer 3, and the metal sleeve 5 are brazed to each other, and the rotary shaft is the metal member 4 arranged so as to have a slight gap G from the end surface of the second buffer layer 3. The metal sleeve 5 and the metal sleeve 5 are electron-beam welded at the joint S.

In the case where the metal sleeve 5 and the metal member 4 are joined by electron beam welding, the hardness of the rotating shaft, which is the metal member 4 that has been quench-hardened in advance, does not deteriorate.

FIG. 3 is an example in which the joining structure of the present invention is applied to a graphite tile fixture on the inner wall of a fusion reactor, and a ceramic member made of a silicon carbide sintered body using boron (B) as a sintering aid. The first buffer layer 2 and the second buffer layer 3 are brazed to the pin 1 and the graphite tile 7 and the holder 8 made of a silicon carbide sintered body are assembled in advance, and then the metal sleeve 5 is used.
Brazed. After that, the metal member 4 having the screw portion arranged so as to have a slight gap G from the end surface of the second buffer layer 3 is electron beam welded to the metal sleeve at the joint portion S. The obtained graphite tile fixture is screwed and fixed to a screw portion (not shown) provided on the inner wall of the fusion reactor.

[Advantage of Invention] According to the joining structure of the ceramic member and the metal member of the present invention, the thermal strain to the metal sleeve due to the heat treatment of the metal member is mitigated, and the thermal strain of the metal sleeve is almost eliminated to the ceramic member. In addition to not affecting the ceramic member and the metal sleeve even in a high temperature atmosphere, the metal member itself does not break and has excellent heat insulating properties, high bonding strength, and a highly reliable ceramic member and metal. A composite structure of members can be obtained.

[Brief description of drawings]

FIG. 1 is a partially broken sectional view showing a joining structure of a ceramic member and a metal member according to the present invention, and FIG. 2 is a partially broken sectional view showing an embodiment in which the joining structure of the present invention is applied to a radial rotor, FIG. 3 is a sectional view showing an embodiment in which the joint structure of the present invention is applied to a graphite tile fixture on the inner wall of a fusion reactor, and FIG. 4 is a partially broken cross section showing the joint structure of a conventional ceramic member and a metal member. It is a figure. DESCRIPTION OF SYMBOLS 1 ... Ceramics member 2 ... 1st buffer layer 3 ... 2nd buffer layer 4 ... Metal member 5 ... Metal sleeve G ... Gap

Claims (1)

(57) [Scope of utility model registration request] 1. A first buffer layer and a second buffer layer are sequentially brazed to an end surface of a ceramic member, and a metal member is disposed so as to have a slight gap with the end surface of the second buffer layer. A metal sleeve is fitted so as to cover the end of the ceramic member, the first and second buffer layers, and the end of the metal member,
A joined structure of a ceramic member and a metal member, characterized in that the ceramic member and the metal member are joined and integrated via the first and second buffer layers.