JPH05170565A - Method for carrying out treatment for joining nitride ceramics to metal - Google Patents

Abstract

PURPOSE:To obtain the subject joined material capable of producing in simple step, high in joining strength and action for relaxing heat stress and capable of preventing occurrence of crack in ceramics. CONSTITUTION:Foil of 100% or nearly 100% active metal (e.g. Ti or Zr) is put on the ceramic side of a joining part of nitride ceramics (e.g. AlN or Si3N4) and metal (e.g. Cu or Ni) and a foil of a transition metal (e.g. Cu or Ni) having purity similar to the active metal foil is put on the metal side and short-term heat treatment is carried out at >=900 deg.C, preferably 920-1050 deg.C for about 1-20min to provide the subject joined material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for joining nitride ceramics and metal.

[0002]

2. Description of the Related Art Recently, ceramic materials have been used in a wide range of fields such as structural materials and functional materials due to their excellent characteristics. In many cases, ceramics are used to form parts, but in order to use ceramics in more fields, it is necessary to be able to bond with metals. In this case, structural parts are required to have sufficient joint strength, while functional parts are required to have continuity at the joint interface.
However, ceramics and metals have different atomic bond states, so when bonding metals and ceramics, their chemical properties such as reactivity, thermal expansion coefficient,
Physical properties such as electrical conductivity differ greatly. Therefore, it is considerably difficult to wet both members well and perform highly reliable alloy-like joining.

By the way, conventionally, a method using an active metal (US Pat. No. 2,857,663) is known as one of the methods for joining ceramics and metal. This method takes advantage of the fact that active metals such as Ti and Zr and alloys of transition metals such as Cu and Ni lower their melting points by several hundreds of degrees Celsius, thereby oxidizing metals and alumina, forsterite, beryllia, zirconia, etc. This is a method of joining physical ceramics.

However, when a ceramic-metal bonded body, particularly a nitride ceramics such as AlN or Si ₃ N ₄ and a metal such as Cu or Ni, is manufactured by the above-mentioned method, the bonded body is subjected to thermal shock. When added, thermal stress is generated due to the difference in thermal expansion between them, and there is a defect that cracks occur in the nitride ceramics. That is, the thermal expansion coefficient of the conventional oxide ceramics as shown in the following Table was ^{8.6 × 10 -6 /℃~13.5×10 -6 / ℃} ,
The coefficient of thermal expansion of AlN or Si ₃ N ₄ is about 5 × 10 ^-6 /
℃, 2.5 × 10 ^-6 / ℃ is larger than Cu, Fe
Shows a value close to the coefficient of thermal expansion of. For this reason, a larger thermal stress is generated in the bonded body of Cu, Fe, etc. of the nitride ceramics than in the bonded body of the oxide ceramics and the metal, and cracks are easily generated in the ceramics.

[0005]

[Table 1] For this reason, a brazing filler metal containing an active metal and a brazing filler metal are intercalated with a thin metallic plate made of Cu, Cu alloy, Al or the like, and the brazing filler metal and the metallic brazing plate are spot-welded and integrally joined. A method of joining a nitride ceramics and a metal by using a material (Japanese Patent Laid-Open No. 56-163093) has been proposed.
Also, a joined body has been developed in which a brazing material containing an active metal is diffused into a ceramic and a metal base material. However, these methods and the like have problems in that they involve complicated steps and heat treatment for a long time. Therefore, a bonded body of a nitride ceramic and a transition metal, which can be manufactured by a more simplified process and which has a high bonding strength and can relieve thermal stress, has been earnestly desired.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a bonded body of a nitride ceramic and a metal, which can be manufactured by a simple process, has a high bonding strength, a high thermal stress relaxation effect, and can prevent the crack generation of the nitride ceramic. The present invention is intended to provide a method of joining treatment.

[0007]

Means and Actions for Solving the Problems The present inventors have succeeded in developing a joining treatment method for producing a joined body of a nitride ceramic and a metal, paying attention to the points described below.

That is, the brazing material containing an active metal such as Ti or Zr has good wettability with the nitride ceramics. It has already been confirmed that this is because Ti and Zr react with nitride ceramics to form a nitride (TiN, ZrN, etc.).

Ti and Zr are intermediate values of the coefficient of thermal expansion of the nitride ceramics of AlN or Si ₃ N ₄ and the metals of Cu or Ni, and are 8.9 × 10 ^-6 / ° C. and 5 × 10 5, respectively. ^-6 /
Having a ° C.

Further, the coefficient of thermal expansion of an alloy composed of metals A and B is generally expressed by the following equation.

[0011]

[Formula 1] α alloy = αA MA + αB MB [where α is the coefficient of thermal expansion, A and B are elements, and M is the concentration of the alloy component. ]] Is represented. That is, when considering an alloy of Zr and Cu, the composition and the thermal expansion coefficient have a proportional relationship as shown in FIG.

From the above-mentioned investigation results, however, in a joined body of a nitride ceramics such as AlN or Si ₃ N ₄ having a relatively small thermal expansion coefficient and a metal such as Cu or Ni,
The joining portion is rich in an active metal nitride layer from the nitride ceramics side, at least one layer of active metal-rich (99 to 50% by weight) transition metal, and at least one layer of transition metal (99 ˜50% by weight) and the active metal and the composite metal are sequentially arranged to form a multilayer structure, the difference in the coefficient of thermal expansion between the nitride ceramics and the transition metal can be gradually reduced at the joint. It has been found that the thermal stress between the two can be reduced to prevent cracking of the nitride ceramics, and a bonded body in which the nitride ceramics and the transition metal are firmly bonded is formed. The effect of relaxing the thermal stress of such a bonded body is also apparent from the following description.

That is, when the stress generated in the bonded body of ceramics and metal is σ,

[0014]

[Equation 2] [Wherein Δα is the difference in coefficient of thermal expansion between ceramics and metal, ΔT is the temperature difference between molding temperature and room temperature, E is Young's modulus, t is thickness, c and m are ceramics and metal, respectively. ]] Is represented. From this equation, it can be seen that the stress σ generated is small when Δα is small in the joined body under the same conditions other than Δα.

In order to form a bonded body as described above, the present invention provides 100% bonding to the nitride ceramics and the metal.
Alternatively, a transition metal foil having a purity similar to that of the active metal foil of nearly 100% is interposed so that the active metal foil is located on the ceramic side and the transition metal foil is located on the metal side, and then 900
A method for joining metal and nitride ceramics is characterized by performing heat treatment at a temperature of ℃ or more.

In the bonding treatment method according to the present invention, the heating temperature is 900 ° C. or higher, preferably 920 to 1050 ° C.

According to the bonding treatment of the present invention, an active metal nitride layer, an alloy layer with an active metal-rich transition metal, and an alloy layer with a transition metal-rich active metal are formed between the nitride ceramics and the metal. The joint portion is formed, and the joint body having the good characteristics described above is manufactured.

[0018]

【Example】

Example 1 First, between the AlN member and the Cu member, Zr having a thickness of 50 μm was used.
With a foil interposed, and a thickness of 50μ between the Zr foil and the Cu member.
Cu foil of m was interposed. Then, it was heat-treated at 920 ° C. for 5 minutes to manufacture a joined body of the AlN member and the Cu member.

The obtained joined body is a ZrN layer, 95 to 98 atomic% Z between the AlN member and the Cu member from the AlN member side.
A joint part having a multilayer structure in which an alloy layer of r-remainder Cu and an alloy layer of 75 atom% Cu-remainder Zr were sequentially arranged was formed. Cross section of such a bonded body with an optical microscope 1
When observed at a magnification of 00, no cracks were found on the AlN member.

Further, a Cu tensile test jig was soldered to the Cu member of the obtained joined body with Pb-Sn solder, and a constant speed tensile test was carried out at room temperature. As a result, it was confirmed that the fracture always occurred at the soldered portion, and the joined body was firmly joined at the joined portion of the multilayer structure. Example 2 A Ti foil having a thickness of 10 μm was interposed between the AlN member and the Cu member, and a Cu foil having a thickness of 100 μm was interposed between the Ti foil and the Cu member. Then, the same heat treatment as in Example 1 was performed to manufacture a joined body.

The obtained joined body was composed of an AlN member and a Cu member, a TiN layer, and 95 to 98 atomic% T from the AlN member side.
A junction having a multi-layer structure in which an i-balance Cu alloy layer and a 75 atom% Cu-balance Ti alloy layer were sequentially arranged was formed. When the cross section of such a bonded body was observed in the same manner as in Example 1, no cracks were found in the AlN member. Also, the bonding strength was extremely high.

[0022]

As described in detail above, according to the present invention, it is possible to manufacture by a simple process, the bonding strength is high, and the thermal stress relaxation effect upon thermal influence is high, so that the cracking of nitride ceramics occurs. It is possible to provide a bonded body of a nitride ceramic and a metal, which is effective for various functional parts that can prevent the above.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a function of a composition and a coefficient of thermal expansion in a Zr—Cu alloy.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Yamazaki 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Inside the Toshiba Research Institute Co., Ltd. (72) Inventor Makoto Shirakane, Komukai Toshiba, Kawasaki-shi, Kanagawa Town No. 1 Incorporated company Toshiba Research Institute

Claims (1)

[Claims] 1. At the joint of nitride ceramics and metal, 10
A transition metal foil having a purity similar to that of the active metal foil of 0% or nearly 100% is interposed so that the active metal foil is located on the ceramic side and the transition metal foil is located on the metal side. Then
A method for joining a nitride ceramic and a metal, which comprises performing a heat treatment at 900 ° C. or higher for a short time of about 1 to 20 minutes.