JPH04108675A - Ceramics-metal bonded body - Google Patents

Abstract

PURPOSE:To improve the bonding strength by reducing the stress of the surface of a ceramic member by machining or releasing the stress of the surface of the bonded body including the maximum principal stress point by irradiating the surface with an energy beam. CONSTITUTION:The surface of a ceramic member 12 of Si3N4, etc. is machined by a barrel finishing machine to reduce its stress, the surface roughness (Rmax)is controlled to about 4mum, and a non-oriented compressive residual stress of about 80 MPa is imparted. The member 12 and a metallic member 13 of steel, etc., are heated in vacuum with Cu as a buffer 14 and brazed together with an active metal to obtain a ceramics metal bonded body 11. Meanwhile, ceramic members 32a and 32b and a metallic member 33 are bonded with a buffer metal Cu 34 in-between to obtain a ceramics-metal bonded body 31. The bonding interface including the maximum principal stress point extending over the ceramics 32a and 32b and metallic member 33 with the Cu sheet 34 as the center is irradiated with an energy beam such as a laser beam to release its stress.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a ceramic-metal bonded body in which a ceramic member and a metal member are bonded.

(Prior Art) Ceramics are characterized by being lightweight and high hardness, and the high strength and wear resistance due to this hardness are actively utilized.

Furthermore, the superiority of ceramics is exhibited at high temperatures of 1000° C. or higher. For example, silicon nitride has 120
It has heat resistance up to 0°C, while silicon carbide has heat resistance up to nearly 1500°C, and it can be expected to significantly improve thermal efficiency when applied in temperature ranges that metals cannot withstand.

However, since ceramics are inherently brittle materials, it is difficult to use them alone; therefore, it is rational to use ceramics only in areas where properties are required and to use them in combination with other materials.

As bonding techniques for such ceramics, methods using mechanical bonding or organic adhesives, or chemical bonding methods that involve some kind of reaction such as diffusion of constituent elements at the interface, solid solution, or reaction product formation, have been attempted. ing.

In the case of structural ceramics, the mainstream chemical bonding methods for ceramics include solid-phase bonding, which involves direct bonding without inclusions, and active metal methods, which use insert materials that easily react with ceramics. For example, metallization method is used.

For example, in order to bond silicon nitride, which is a typical structural ceramic, to a metal member, there are two methods: interposing an active metal such as Ti and using eutectic formation with the active metal; Metal brazing is often used, in which a ductile metal (usually Cu) is placed between the ceramic and the metal as a buffer material to alleviate the stress, and the metal is soldered with a brazing material such as Ag-Cu-Tj. has been done.

(Problems to be Solved by the Invention) However, ceramics have a smaller thermal expansion than metals, and especially silicon nitride and silicon carbide, which have high heat resistance and are useful as structural ceramics, have a very small thermal expansion.

Therefore, when joining ceramics and metal materials,
Residual stress is generated during the cooling process after bonding due to the difference in thermal expansion, causing various problems.

In other words, large residual stress is generated near the joint, especially near the singular point at the joint interface, and joint strength can be significantly reduced due to synergy with external stress, or the maximum stress point may be reduced due to the cooling process after joining or thermal cycles. This causes cracks to occur, leading to destruction of the ceramic.

Under these circumstances, there is a demand for a ceramic-metal bonded body that can reduce the residual stress on the surface of the ceramic, improve the bonding strength between the ceramic and the metal member, and take advantage of the excellent properties of the ceramic.

The present invention was made to solve these problems, and the purpose is to provide a healthy and stable ceramic-metal bonded body that has high bonding strength between ceramic and metal members, does not generate cracks, etc. shall be.

[Structure of the Invention] (Means for Solving the Problems) The ceramic-metal bonded body of the first aspect of the present invention is a bonded body of a ceramic member and a metal member, and the surface of the ceramic member is machined. It is characterized by having been subjected to stress reduction treatment that imparts non-directional compressive stress.

The ceramic-metal bonded body of the second invention is a bonded body of a ceramic member and a metal member, and the surface of the bonded body including the maximum principal stress point is subjected to stress release treatment by energy beam irradiation. It is characterized by

In the first invention, methods for performing stress reduction treatment include, for example, machining methods such as barrel polishing, shot peening, and honing. A stress reduction treatment is applied to impart a strong compressive stress.

The stress reduction treatment may be applied to the entire surface of the ceramic member, or may be applied locally to the most stressed portion.

Ceramic members with such non-directional compressive stress remaining inside can reduce the tensile stress generated on the ceramic surface when bonded to metal members, and maintain a healthy ceramic-metal bonded body. Obtainable.

In the second invention, examples of the energy beam used in the stress release treatment include energy beam bundles such as electron beams, far infrared rays, lasers, ion beams, SOR light, and X-rays.

These energy beams are applied to the ceramics after bonding.
Irradiation is applied locally to the area containing the maximum principal stress point on the surface of the metal bonded body, and is applied only to the ceramic component side of the bonded body, only to the metal component side, or to both the ceramic component and the metal component by sandwiching the joint interface of the bonded body. Irradiation is applied to the joint area including the maximum principal stress point across.

In the present invention, irradiation with these energy beams exhibits an annealing effect.

Annealing is a treatment method that reduces residual stress in a molded body by heating it for a long time at a temperature lower than the thermal deformation temperature of the material. In the present invention, for example, for silicon nitride ceramic members, 063 ~2
When irradiating silicon nitride ceramics and steel materials, irradiation is preferably performed at 4aO to 600°C for 0.1 to 5 hours.

By such stress release treatment using energy beam irradiation, stress remaining in the bonded body due to the difference in thermal expansion during bonding is relaxed and released.

Particularly, local treatment is effective because it does not impair the properties of each component of the joined body and leads to cost reduction.

Further, the ceramic members and metal members used in the present invention are not particularly limited, and examples of ceramics include silicon nitride, silicon carbide, alumina, zirconia, and sialon, and examples of metals include steel materials, copper plates, heat-resistant alloys, cemented carbide, and W.
It is applicable to various members such as pure metals such as SNo and Nf.

(Function) An example of residual stress distribution in a ceramic-metal bonded body is shown in Fig. 9.

This is a Si3N4 composite of Sf3N4-Cu-8teel plate-shaped joint (Cu is inserted as a buffer material).
Fig. 9(a) is the measurement result at y-0,
1 mm, (b) shows the distribution of normal stress and shear stress on a line away from the y-0,5txtx bonding interface.

At the extreme end, which is the singular point of the zygote, σR8, σ2.
Any normal stress becomes a tensile stress, especially when σRY is 2
It shows a large value exceeding 00 MPa.

In other words, this tensile stress means that the stress acting in the direction perpendicular to the bonding interface A between the ceramic member 1 and the metal member 2 (in the direction of arrow Y) is large, as shown in FIG.

On the other hand, in the ceramic-metal bonded body of the first invention, stress reduction treatment is performed on the ceramic members by machining before joining, and non-directional compressive stress is applied to the ceramic members.

This compressive stress cancels out the tensile stress in the direction of arrow Y,
Reduces residual stress after bonding.

In addition, in the ceramic-metal bonded body of the second invention, the surface of the bonded body including the maximum principal stress point after bonding is subjected to stress release treatment by energy beam irradiation to release residual stress and maintain the soundness of the bonded body. We aim to make this possible.

These reduce the residual stress of the ceramic-metal bonded body and improve the bonding strength.

(Example) Next, examples of the present invention will be described.

Example 1 FIG. 1 is a diagram showing a ceramic-metal bonded body according to an example of the present invention.

The ceramic-metal bonded body 11 shown in the figure is made by joining a silicon nitride ceramic 12 with a cross section of 125 m x 1.2 m and a length of 20 mm to a 545C steel material 13 of the same size by active metal brazing. The surface of the silicon nitride ceramic 12 is subjected to stress reduction treatment by barrel polishing.

This ceramic-metal bonded body 11 is produced as follows.

First, the entire surface of the silicon nitride ceramic 12 is subjected to barrel polishing using a wet centrifugal barrel polishing machine at a rotation speed of 1100 rpm and a polishing time of 1 hr.

By this stress reduction treatment, silicon nitride ceramic 12
The surface roughness was Rmax 4 μm, and a non-directional compressive residual stress of 80 MPa was applied.

Next, this silicon nitride ceramic 12 and the 545C steel material 13 are joined by active metal brazing at 830° C. for 6 minutes in a vacuum using Cu as a buffer material.

When the bending strength of the ceramic-metal bonded body according to this example was measured, a result of 370 MPa was obtained.

On the other hand, for comparison, a ceramic-metal bonded body was prepared under the same conditions as this example except that barrel polishing was not performed on the silicon nitride ceramic, and the bending strength was measured. Then, the bonded body of this comparative example had a low value of 320 MPa.

Example 2 FIG. 2 is a diagram showing a ceramic-metal bonded body according to another example of the present invention.

The ceramic-metal bonded body 21 shown in the figure consists of a silicon nitride ceramic 22 with a cross section of 10 m × 3-■ and a length of 20-■, and a 5US304 material 23 of the same size.
The surfaces of the silicon nitride ceramics 22 are subjected to stress reduction treatment by honing.

This ceramic-metal bonded body 21 is produced as follows.

First, the silicon nitride ceramic 22 was sprayed at a rate of 100 g/min from a nozzle with a diameter of 0.5 layers.
Spraying was done using glass beads at a speed of 15 seconds/sec.
Perform et honing.

By this stress reduction treatment, the silicon nitride ceramic 22
The surface roughness was Rsax8μs, and a non-directional compressive residual stress of 120MPa was applied.

Next, this silicon nitride ceramic 22 and 5US30
4 materials 23 are joined by active metal brazing in vacuum at 830° C. for 6 minutes.

When the bending strength of the ceramic-metal bonded body according to this example was measured, a result of 150 MPa was obtained.

On the other hand, for comparison, a ceramic-metal bonded body was fabricated under the same conditions as this example without honing the silicon nitride ceramic, and its bending strength was measured. As a result, cracks occurred in the joined body of this comparative example near the joint interface between the two members, resulting in a defective product that could not be used as a product.

Example 3 FIG. 3 shows a ceramic material which is one of the examples of the present invention.
It is a figure showing a metal joint.

The ceramic bonded body 31 shown in the same figure has a cross section of 2hi x 3 mm and a length of 20 m between silicon nitride ceramics 32a and 32b.
*This is a joined body in which 545C steel material 33 having a length of 31Il and a length of 3+g is sandwiched.

Silicon nitride ceramics 32a and 32b and 545C
A copper plate 34 is inserted between the steel member 33 and the steel member 33 as a buffer metal.

In addition, silicon nitride ceramics 3 are made around the copper plate 34.
The bonding interface between 2a and 32b and the 545C steel material 33 is subjected to stress release treatment by laser irradiation.

This ceramic-metal bonded body 31 is made by bonding each constituent member in advance using a normal method, and then attaching a diameter of 2.0 square meters near the bond singular point including the maximum principal stress point of the bonded body and around the center of the bond interface. 5K11 CO in 5 locations in total
Partial annealing was performed by irradiating two lasers for 5 minutes.

As shown in Fig. 4, the maximum principal stress appears in the axial direction of both ends of the bond at a portion approximately 0.51 m from the bond interface between Cu, which is a buffer metal, and silicon nitride, toward the silicon nitride side. Laser irradiation is performed to include the

After such stress release treatment, the residual stress distribution on the maximum principal stress line along the above-mentioned bonding interface was measured. As a result, the residual stress value at the maximum point was 120 MPa.

On the other hand, the maximum principal stress value without laser irradiation is 3]
It was 0 MPa.

These results are shown in FIG. The results of the example are shown as a solid line,
The results of the comparative example are shown by dotted lines.

Example 4 FIG. 6 shows ceramics according to an example of the present invention.
It is a figure showing a metal joint.

A ceramic bonded body 41 shown in the figure has a Cu plate 43 bonded onto an alumina substrate 42 by the DBC method.

A portion of each corner of the Cu plate 43 was annealed by irradiating it with a CO2 laser (diameter 1.5 mm) of 5.nu. for 10 minutes while scanning as shown in FIG. 644.

Subsequent thermal shock test (300'C - water quenching at 0°C)
) withstood.

On the other hand, peeling occurred in the Cu plate in the case where the annealing treatment was not performed.

Embodiment 5 Figure M7 is a diagram showing a ceramic-metal bonded body which is one of the embodiments of the present invention.

A ceramic bonded body 51 shown in the figure has four Cu plates 53 dispersively bonded to an aluminum nitride substrate 52 by a direct bonding method.

A portion of each corner of this Cu plate 53 is partially annealed by irradiating a YAG laser of 3KV for 20 minutes with a diameter of 2.times.1.

A thermal cycle test was conducted on the aluminum nitride substrate subjected to the stress relief treatment as described above and the aluminum nitride substrate not subjected to the stress relief treatment.

The results showed that the substrates that were irradiated with laser had twice the lifespan of the substrates that were not irradiated with laser irradiation.

Embodiment 6 FIG.
It is a figure showing a metal joint.

A ceramic-metal bonded body 61 shown in the figure has been irradiated with far infrared rays.

This is a PGA with an AIN 8-layer structure, in which the AIN is metallized, N1 plated, Ag brazed, and a KOv lead 62 is connected. The area around the joint 63 is irradiated with far infrared rays, and the AI is higher than that without this treatment.
No defects such as N breakage occurred.

In addition, 64 in the figure is an enlarged view of the vicinity of the joint 63, and K
An anil portion 65 exists concentrically around the OV lead 62.

As is clear from these results, the ceramic-metal bonded body subjected to stress reduction treatment or stress release treatment has
It is possible to absorb and reduce residual stress caused by non-directional compressive stress applied to ceramic members or thermal expansion difference during bonding of bonded bodies, and energy beams can also be used for bonded bodies with residual stress. We were able to alleviate the stress and improve the bonding strength through partial annealing.

[Effects of the Invention] As explained above, according to the ceramic-metal bonded body of the present invention, non-directional compressive stress can be applied to the surface of the ceramic member, and the area containing the maximum principal stress point of the bonded body can be By performing energy beam irradiation, it is possible to reduce the residual stress generated in the bonded body, improve the bonding strength, and obtain a healthy ceramic-metal bonded body with a low incidence of defects such as cracks.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a ceramic-metal bonded body according to an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing a ceramic-metal bonded body according to another embodiment of the present invention, and FIG. 4 is a diagram showing a ceramic-metal bonded body according to another embodiment of the present invention. FIG. 5 is a diagram showing the planar distribution of the maximum principal stress near the interface, FIG. 5 is a diagram showing the measurement results of residual stress distribution in a ceramic-metal bonded body, and FIGS. 6 to 8 are diagrams showing still other embodiments of the present invention. FIG. 9 is a diagram showing an example of residual stress distribution in a conventional ceramic-metal bonded body, and FIG. 10 is a diagram for explaining a conventional ceramic-metal bonded body. 11.21...Ceramics-metal bonded body, 12.2
2...Silicon nitride ceramics, 13.23...Metal member, 34...Copper plate, 35...Irradiation trace, 42...Alumina substrate, 43...Copper plate, 52...
Aluminum nitride substrate, 61... Ceramic-metal bonded body, A... Bonding interface. Figure 1 Applicant: Toshiba Corporation

Claims (2)

[Claims] (1) A joined body of a ceramic member and a metal member,
A ceramic-metal bonded body, characterized in that the surface of the ceramic member is subjected to stress reduction treatment that applies non-directional compressive stress by machining. (2) A joined body of a ceramic member and a metal member,
A ceramic-metal bonded body characterized in that the surface of the bonded body including the maximum principal stress point of the bonded body is subjected to stress release treatment by energy beam irradiation.