JPS60246279A - Bonded structure of ceramic body and metal body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a bonding structure between a ceramic body and a metal body, and reduces the difference in thermal expansion coefficient between the ceramic body and the metal body, thereby reducing the thermal expansion of both. This is intended to solve problems such as cracking of the ceramic body caused by differences in coefficients, and is effective for joining the ceramic element and metal sleeve of a ceramic glow plug, for example.

(Prior Art) Currently, the use of ceramics in various fields is being studied1), but a problem often arises in such cases is the method of joining the ceramic body and the metal body. As a general joining method, for example, as described in Japanese Patent Application Laid-Open No. 55-51777 (M) on the ceramic surface.

There is a method of metallizing it with metal, applying metal plating to the metalized surface, and then brazing it with the metal body to be joined.

However, because the coefficient of thermal expansion between the metal body and the ceramic body is significantly different, if the ceramic body is used in a manufacturing process that is exposed to high temperatures such as a brazing process or under conditions where the joint part is exposed to high temperatures, the ceramic body may Problems often occurred such as the crank becoming stuck or the joints breaking. Therefore, in order to solve the above problem, it may be possible to use a metal such as Kovar (trade name), which has a coefficient of thermal expansion close to that of a ceramic body, as the joining metal, but Kovar is extremely expensive and costs is the cause of the increase.

(Problems to be Solved by the Invention) The present invention attempts to reduce the stress caused by the difference in coefficient of thermal expansion (2) between the ceramic body and the metal body, thereby suppressing the sealing from breaking of the ceramic body. It is something to do.

(Means for Solving the Problems) The present invention has a metal layer on the surface of a ceramic body, and a metal layer in which inorganic particles are dispersed, formed on the metal layer, and a metal layer in which inorganic particles are dispersed. It has a structure in which a metal body is connected to the layer through a brazing material.

(Example) In FIG. 1, a heating element 1 made by sintering a mixture of molybdenum disilicide (MOSi2) and silicon nitride is bonded to the outer end surface of a support member 2 of a sintered body of a mixture of silicon nitride and aluminum oxide. - Tungsten glue 1$3a, 3b connected to the heating element 1 is embedded in the support member 2. A pipe-shaped metal sleeve 4 is attached to the outer periphery of the support member 2.
One end of a cylindrical metal body 5 is joined to the sleeve 4. An electrically insulating bushing 8 is interposed in the opening at the other end of the metal body 5 to form a tlJ heart electrode 7, and the center electrode 7 and bushing 8 are fixed to the body 5 with a mounting nut 9. The nut 9 and the body (3) are connected to the sole by the O-ring 0. Lee-1
In addition to wire 3b, vli+ is connected to the center electrode by a holding pillow, and wire 1 of wire 3a is connected to metal sleeve 4.
is connected to. The glow plug is fixed in a perforated hole in the combustion chamber wall of the enclosure by means of a screw 51 formed in its body 5.

When this glow plug is energized, the current flows from the center electrode 7 through the poled pin 6 and the goo 1 wire 3b to the heating element, and further flows through the -l' wire 3d from the metal sleeve 4 to the metal tenon 5. Grounded.

The ceramic body and the metal body are bonded using ceramic support +
This is done between A2 and the metal sleeve 4.

Support part (A2 is 5j3Na60 mol%, Al 20
A mixture of 140 mol % and sintered under pressure using a Honoi press machine was used, and TiO, + (] weight %) was applied to the surface of the support member 2 in terms of MO gold and non-metallic weight %.

S! Adding an organic solvent to the mixture with 02 (5% by weight),
The paste is screen-printed and baked at 1350°C in an atmosphere containing hydrogen, nitrogen, a) or water (4) to coat the surface of the support member 2 with Mo.
A metal layer consisting of the following was provided. Electroless N on the surface of this metal layer
Two types of samples were made: one with normal Ni electrolytic plating and one with composite plating in which ceramic particles were diffused in the electrolytic plating layer. The temperature between the plating layer and the metal sleeve is 780°C in a hydrogen atmosphere.
I did silver brazing. The above composite plating is nickel sulfamate 3QOg/7! To a solution containing 30 g/β of boric acid and 300 g/l of concentrated nickel bromide solution, hensyl ammonium salt was added as a dispersant, and the average particle size was 1.
It can be obtained by adding 50 g/l of SiN4 with a particle diameter of less than μm and electrolyzing it.

FIG. 2 shows a cross-sectional view of a product subjected to normal NI plating, and FIG. 3 shows a cross-sectional view of a product subjected to composite plating. An MO layer 11 is provided on the surface of the ceramic support member 2, and an electroless plated Ni layer 12. Electroplated N1 layer 13. Brazed Ag layer 1
4 is present and joins with the stainless metal sleeve 4. On the other hand, in the case of composite metal (5), there is a contact point N15 instead of the electroplated Ni layer + 3, and the bonding plating layer 15 is made of silicon nitride particles inside the bonding plating Ni layer + 5b. 15a.

FIG. 4 shows a cross-sectional view of the ceramic support member 2 and metal sleeve 4 joined as described above, which were diamond-polished in the length direction of the ceramic heating element 1. Cracks 16 are found in joints with such a structure.
was observed. FIG. 5 is a diagram in which the element is cut in the direction of the cross section shown in FIG. On the other hand, in the case where a composite plating layer was provided and the structure was joined as shown in FIG. 3, the crack LJ as described above was not observed. For the test, we manufactured 10 pieces of each type and compared the occurrence of cracks after brazing. In the case of I(r), cracks were observed in 8 out of 10, but in the case of composite plating as shown in Figure 3, no cracks were observed out of 10. This occurs when Ag(6) brazing is performed between the plating layer and the metal sleeve in an H2 atmosphere, and the metal sleeve 4
This is due to the difference in thermal expansion between the ceramic support member 2 and the ceramic support member 2. Since the composite plating layer contains ceramic particles with small thermal expansion in the plating metal layer, the coefficient of thermal expansion of the composite plating layer is lower than that of a normal plating layer and approaches the thermal expansion of the ceramic support member 2. It is believed that an intermediate layer for mitigating thermal expansion is provided between the sleeve and the support member 2, and as a result of mitigating the stress caused by the difference in thermal expansion, it is possible to prevent the occurrence of cracks. Although the electroless plating Ni layer is provided on the MO layer in FIG. 2.3, this need not be done in order to make the electrolytic M plating easier. Further, although this embodiment has been described with reference to the joining of the metal sleeve 4 and the rod-shaped ceramic support member 2, the present invention can of course be applied to the joining of a metal plate and a ceramic plate.

In addition, the inorganic particles dispersed in the composite plating layer are Si
In addition to 3N4, metal oxides such as A7!203, ZrO2, metal carbides such as SiC and TiC, and Si
Totally flexible nitrides such as 3N4, gold (such as MoS i 2)
7) Metal borides such as metal silicides and CrB2 may be used.

(Effect of the invention) A metal layer containing inorganic particles is present in a structure in which a metal layer is present on the surface of a ceramic body, and a metal layer containing inorganic particles is present between this metal layer and a metal body to be bonded. has a coefficient of thermal expansion between that of the ceramic body and that of the metal body, so the partner's! 'Oh! The stress caused by the difference in lIv tension can be alleviated, and damage to the ceramic body caused by the difference in thermal expansion between the metal body, the ceramic body, and the resin body can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of application to which the structure of the present invention is applied;
FIG. 2 is a schematic sectional view showing a conventional joining structure to explain the operation of the present invention, FIG. 3 is a schematic sectional view showing an embodiment of the present invention, and FIG. 4 is a detailed explanation of the present invention. Figures 5 and 84 A-A of Figure 1 for detailed explanation of the present invention
FIG. 2... Ceramic support part) A, 6... Metal sleeve,
11.12... Metal layer, 14... Brazing metal, 15...
Composite (8) Plating layer, 15a... Inorganic particles, 15b... Metal layer. Representative Patent Attorney Takashi Okabe (9) Figure 1-1 Figure 2 Figure 5 1^

Claims (1)

[Claims] The ceramic body has a metal layer on the surface thereof, and a metal layer in which inorganic particles are dispersed formed on the metal layer, and the metal body is connected to the metal layer in which inorganic particles are dispersed through a brazing material. A bonding structure between a ceramic body and a metal body.