JPH0446068A - Joined body composed of ceramic body and metal body - Google Patents

Abstract

PURPOSE:To enhance bonding strength by forming an active middle layer reacting with the principal constituent of a ceramic body on the surface of the ceramic body contg. a specified amt. of a spinel compd. and joining the ceramic body to a metal body. CONSTITUTION:The surface of an Al2O3-based ceramic sintered body contg. >=70wt.% spinel compd. such as MgAl2O4 is polished and washed with a solvent. An active metal reacting with the principal constituent of the ceramic body, e.g., Ti or Zr and an Ag-Cu alloy as a brazing filler metal are put on the washed surface to be joined and a metal body such as stainless steel is further put. A middle layer is then formed by heating to a prescribed temp. in vacuum or in an inert gaseous atmosphere and the ceramics sintered body is joined to the metal body with the middle layer in-between to obtain a joined body having superior bonding strength and radiation resistance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a joined body of a ceramic body and a metal body,
More specifically, the present invention relates to a bonded body with excellent radiation tolerance, bonding strength, and airtightness.

INDUSTRIAL APPLICATION This invention is utilized for the components used in the trench boundary exposed to radiation, such as a neutron, for example, the components of a nuclear reactor, a nuclear fusion reactor, etc.

[Conventional technology]

As a conventional joined body of a ceramic body and a metal body, for example, an ion chamber type medium-wavelength detector as shown in the figure is known. In this detector, supporting ceramic bodies 3a and 3b that insulate and support the anode 2 of the ionization chamber 1 are brazed to a container (metallic body) 4, which is the cathode, and are connected to the outer conductive ceramic bodies 11a and 11b. A device is known in which the guide cable 10 and the ionization chamber 1 are hermetically isolated by brazing the body 12. In the above, the guide cable side support ceramic body 3as partition wall ceramic body 11a and ll
The airtightness of the ionization chamber 1 is maintained by at least one brazing.

Note that a neutron exchange substance 5 such as uranium is attached to the inner surface of the cathode 4, and an inert ionized gas 6 such as argon is sealed inside the ionization chamber 1, that is, between the anode 2 and the cathode 4. ing.

Furthermore, the materials for the ceramic bodies 3a, 3b, ll & 11b include general alumina, magnesia,
Boron nitride, silica, etc. are known (Japanese Patent Application Laid-Open No. 56-7
No. 0481, No. 57-52877, No. 60-
Since the body of No. 230349 is simply brazed with conventional materials such as silver-copper alloy, its bonding strength and airtightness are insufficient in a superior environment. Moreover, the alumina used for ships is J, Nuc 1. Mata
rl, 122/123 (1984), P, 1386~
Approximately 22 x 10 as reported in 1392
When irradiated with neutrons at a dose of ``n/m'', swelling occurs and the volume increases by 3.5%, causing severe damage.
Cracks occur in the ceramic body. Therefore, in this case, a gap occurs in bonding strength and airtightness.

Furthermore, ceramic body materials other than alumina, such as magnesia, have the same problems as alumina.

The present invention solves the above eight problems, and aims to provide a joined body of a ceramic body and a metal body that has excellent radiation resistance, bonding strength, and airtightness.

[Means for Solving the Problems] The present invention has discovered a spinel compound as a ceramic material with excellent radiation resistance. The reason for setting this blending ratio to 70% or more is to ensure joint strength, airtightness of the joint, and radiation resistance.

The above-mentioned active metal is one that reacts with the main components of the ceramic body other than the grain boundary components, and it does not matter whether or not it reacts with the grain boundary components. Here, grain boundary constituents include sintering aids, impurities originally contained in ceramic raw materials, and the like.

[Effect]

Spinel compounds are described in J. Nucl. Mater.
122/123 (1984), P, 1386-13
22 X 1026n/ as reported in 92
Even with neutron irradiation at a dose of about m2, the volume change is -0
, 39%, which is very small and has excellent radiation resistance. In addition, the active metal is one that directly reacts with the main constituent components of the ceramic, and a bonded body with excellent bonding strength and airtightness can be obtained.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 The joined body of this example is a cylindrical metal body (outer diameter 6 wφ x height 5 Company Ro×
0.6I1m) are joined via an intermediate layer. This sintered body is Mg A 1 * O-90
% and 10% alumina. The metal body is made from copper;
The end surface is the joint surface. The middle layer is titanium (
It is an alloy layer of Ti (hereinafter referred to as Ti), silver, and copper.

This joined body was manufactured as follows.

First, the joint surfaces of the sintered bodies were polished with a #600 abrasive, and then washed with acetone. Next, on this joint surface, Ti foil (thickness 0°01), which is an active metal, and silver 7
A brazing material (thickness: 0.6 mm) of 2% copper and 28% copper was placed, and a metal body was placed thereon so that its end surface was aligned with the joint surface.

Next, this was held in vacuum at 850° C. for 10 minutes to form an intermediate layer, and the sintered body and the metal body were joined via this intermediate layer to produce a joined body.

The bonding strength of this bonded body was 5 kg f/3. Further, the airtightness of the joint of this assembly was 10-'' cc/sec or less in terms of helium leakage.

Note that the joint strength was determined by a tensile strength test using a strength testing machine, and the airtightness was measured using a helium leak detector.

Example 2 Kovar plate (10X10X2 (thickness)) as a metal body
A joined body was manufactured in the same manner as in Example 1 except that 111m was used 5). The strength of this joint is 7Kgf/c
tb", and the hermeticity of the joint was less than 10-" cc/sec.

Example 3 The blending ratio of MgAJz 04 as the ceramic sintered body is 70%, the shape of the sintered body is cylindrical (outer diameter 8 isφ, height 5M), and the active metal usage form is Ti2%- Using brazing material made of 98% copper,
Example 1 was carried out in the same manner as in Example 1, except that a SUS 304 cylindrical body (outer diameter 8 holes, height 4 in order, wall thickness O95) was used as the metal body, and the intermediate layer formation temperature was 1200°C. A zygote was fabricated. The strength of this joint is 3.6K
gf/m1N2, and the airtightness of the joint was 10-1 occ/sec or less.

Example 4 As a ceramic sintered body, a plate-like body with a blending ratio of M g A l 20 s of 85% and a thickness of 5 ml++ was used, and as an active metal, zirconium (hereinafter referred to as , Zr) was used, an alloy of 37.5% gold and 62.5% copper with a thickness ratio of 0.5 was used as the brazing material, and a nickel plate <1 was used as the metal body.
0XI OX2 (l! [su) am) The strength of the wo F'A joint is 3Kgf/me", and the airtightness of the joint is 10
-1 c'cc/sec or less.

Comparative Example A bonded body was manufactured in the same manner as in Example 1, except that the conventional brazing material used in Example 1 (72% silver-28% copper) containing no active metal was used as the intermediate layer. As a result, the brazing material simply peeled off at the interface between the intermediate material and the ceramic body.

Effects of Examples Examples 1 to 4 show that the main constituents (Mg
Since they have an intermediate layer containing an active metal (T1 or Zr) that reacts with A120 (and alumina) to improve the bondability with the ceramic body, they all had excellent strength and airtightness compared to the comparative example. In particular, in Example 2 in which a Kovar plate was used as the metal body, the bonding strength was even better than in Example 1. This is because Kovar plate has a smaller coefficient of thermal expansion.
This is thought to be because the stress generated at the interface was small. In addition, the active metal used to form an intermediate layer may be used in the case of a chair in the form of a foil (Example 1.2), an abnormal brazing material shape (Example 2), or a base-bonded shape (Example 4). It showed good day performance.

Further, it is thought that the higher the blending ratio of MgAlzC)t, the better the bonding strength will be, but even when it was 70% (Example 3), the strength and airtightness were superior to the conventional one.

Furthermore, spinel compounds have excellent radiation tolerance. Even when the blending ratio of MgAla○ is 70%, 85%, or 90% as in Examples 1 to 2, it is a waste that the radiation resistance is significantly superior to that of alumina.

It should be noted that the present invention is not limited to what is shown in the above-mentioned specific examples, but can be variously modified within the scope of the present invention depending on the purpose and use.

That is, as a spinel compound, Mg is replaced with Fe(It)
, Mn (II) etc., replacing A1 with Fe (II[), C
It can be replaced with r([l), etc.

As other compounded ceramic materials, in addition to superimposed alumina, magnuar, boron nitride, silicon nitride, silicon carbide, etc. can be used, and various sintering aids are selected and used depending on these types. . Other active metals that can be used include niobium (Nb) and Mn. Also, the effect of its use is that the intermediate layer can be formed depending on the intermediate layer forming conditions used. As the material of the metal body, other types of stainless steel, titanium, iron-nickel alloy, etc. can be used. The shapes, sizes, etc. of the ceramic body and metal body are selected depending on the purpose and use.

Furthermore, in addition to the ionization type neutron detector shown in the figure, the conjugate of the present invention can be used with other types of neutron detectors such as L'f;U' proportional counter tubes, and various types of ionization chambers. It is also applied to detectors used not only inside nuclear reactors but also outside nuclear reactors, and various parts used in environments exposed to other radiation.

[Effects of the Invention] The bonded body of the ceramic body and metal body of the present invention has an intermediate layer containing an active metal that reacts with the main constituent components of the ceramic body, so the bonding strength and bonding are improved. Excellent airtightness.

Furthermore, since the present invention uses a ceramic body containing a spinel compound, it has excellent radiation resistance, and even when used in an environment exposed to radiation such as neutrons, there is little damage.
The lifespan of the eight items used can be improved. Furthermore, for the same reason, the occurrence of cracks in the ceramic body can be prevented, so that the strength of the joined body and the airtightness of the joint can be maintained.

[Brief explanation of the drawing]

The figure is a sectional view of a main part of a conventional ionization chamber type neutron detector. i, separated from the register, 2; electrode opening, 3; supporting ceramic body, 4;
Cathode (container), 5; Neutron conversion substance, 6; Inert a i
n cass, 10; IK'y-1 ru, 11; partition wall ceramic body.

Claims (1)

[Claims] (1) A ceramic body containing 70% by weight or more of a spinel compound, a metal body, and an intermediate layer that joins the ceramic body and the metal body and includes an active metal that reacts with at least the main constituent components of the ceramic body. A joined body of a ceramic body and a metal body, characterized by comprising: