JP2797020B2 - Bonded body of silicon nitride and metal and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a joined body in which a silicon nitride member and a metal member are joined by a metal paste material, and a method for manufacturing the same.
More specifically, it has a strong bonding strength with little variation,
The present invention relates to a joined body that maintains a strong joining strength even when a thermal shock is repeatedly applied to joined members, and a method for manufacturing the joined body.

[Related Art] Conventionally, as a method for joining a ceramic member and a metal member, there is a method in which the surface of the ceramic member is metallized by some method and then brazed in the same manner as ordinary joining of metals. As a method of metallization (metallization), there is a method in which an active metal (Ti, Zr, etc.) or a high melting point metal (Mo, W, etc.) is deposited on ceramics, or a paste of the metal powder is applied and fired. As a metallization method for non-oxide ceramics, a method using a copper sulfide method is known.

Further, as a method of directly joining by one heat treatment, a solid phase joining method, an active metal joining method, and the like are known. In this case, examples of the solid-phase joining method include a high-pressure joining method using high-temperature heating, a friction welding method, and a voltage application method. On the other hand, as an active metal joining method, there is known a method of directly joining a ceramic and a metal via a silver solder, a nickel solder, or the like containing an active metal (Ti, Zr, or the like). This method is disclosed in
As described in JP-A-81252, "Brazing method of graphite", it can be used for bonding graphite and metal, so that it is widely used.

Furthermore, a mechanical joining method for physically joining is also known.
As these means, bolting, fitting, casting, and the like are performed.

Non-oxide ceramics as well as oxide ceramics such as alumina are used as the ceramics used in these joining methods. In particular, a typical non-oxide ceramic is a silicon nitride member, which is used for automobiles such as turbocharger rotors and glow plugs, taking advantage of the excellent properties of this member such as heat resistance, abrasion resistance and corrosion resistance. It is used as a component or a structural member such as a lining material of a wear-resistant blower for a hot stove. In this case, a silicon nitride member is bonded to a metal and used for these applications.

[Problems to be Solved by the Invention] However, when a ceramic such as a silicon nitride member and a metal are joined by a conventional method, a thermal stress generated at the time of joining or at the time of using the joined body due to a difference in the thermal expansion coefficient between the two is caused by the ceramic member. This causes problems such as destruction of the steel and deterioration of the bonding strength.

As a means for solving these problems, a metallization method using an active metal braze as disclosed in Japanese Patent Application Laid-Open No. In between, a method of inserting a ductile metal such as Cu and Al as a thermal stress buffer layer, and a method of inserting a metal having a small coefficient of thermal expansion such as Mo and W as a thermal stress buffer layer are also employed. Was.

However, it has been found that even when these improved methods are used, the following disadvantages still remain.

(1) In the method of metallizing on ceramic members, many steps are required and the manufacturing cost is increased. In addition, in the case of the direct joining method using active metal brazing, if Cu, Mo, or the like is inserted as a thermal stress buffer material. Manufacturing becomes difficult due to problems such as adjustment of the position between members, and the cost increases accordingly.

(2) In direct joining using active metal brazing, if the paste brazing material used for oxide ceramics such as alumina is directly applied to non-oxide ceramics of silicon nitride members, the bonding strength will vary, and highly reliable parts will be manufactured. Can not.

For this reason, this method uses an active metal braze to directly connect the silicon nitride ceramics to the metal. It has been further desired to develop a joined body which has no cracks in ceramics due to repeated thermal shock and has almost no deterioration in joining strength and a joining method thereof, or an active metal brazing material suitable for a silicon nitride member.

An object of the present invention is to provide a heat stress buffer layer using an active metal brazing material suitable for a silicon nitride member when the silicon nitride member having excellent properties such as heat resistance and wear resistance is directly joined to a metal member. It is an object of the present invention to provide a joined body having excellent repeated thermal shock resistance after joining and having high strength with little variation without inserting a Cu foil or the like.

[Means for Solving the Problems] The present inventors have disclosed in Japanese Patent Application No. 2-59890 as a means for solving the above-mentioned problems in a method of first joining a metal member and a ceramic member. The invention of the "joined body of ceramics and metal and a method of manufacturing the same" has been completed. According to the present invention, 60 to 90% by weight of silver, 3 to 38% by weight of copper, and 1 to 5% by weight of titanium
Using a metal paste brazing material having a composition in which 80 to 90 parts by weight of a metal powder and 10 to 20 parts by weight of a vehicle are blended so as to be 0% by weight, so that a total of 100 parts by weight is used. The feature is that the exposed member (fillet) of the protruding brazing material surrounds the metal member with a protrusion width of at least 0.25 mm or more and is present on the ceramic member, and the product obtained in this manner is It was clarified that the thermal shock resistance of the joined body was greatly improved.

The present inventors have conducted intensive research to achieve a bonded body of silicon nitride and a metal member that can be used as a more reliable component in order to achieve the above object. It has been found that by setting the amount to 4 to 10% by weight, it is sufficiently possible to manufacture a bonded body of silicon nitride and metal having a stronger bonding strength with less variation, and reached the present invention.

That is, the present invention firstly provides a joined body composed of a silicon nitride member and a copper or copper alloy metal member interconnected via a fired active metal paste layer, The area of the member is at least one size larger than the area of the metal member, and at least 0.25 mm
A fillet surrounding the periphery of the metal member with the above band width formed by the baked paste, and having a shear strength after thermal shock of 5 kg / mm ² or more; In addition, a silicon member is made of a copper or copper alloy metal member, and screen-printed substantially 60-95% by weight of silver, 3-38% by weight of copper and 4-10% by weight of titanium are added.
80 to 90 parts by weight of a metal powder and 100 to 20 parts by weight of a vehicle, which are blended to be 100% by weight, are placed in contact with each other via an active metal paste material having a composition of 100 parts by weight in total. The method comprises substantially heating the structure in a vacuum or a non-oxidizing atmosphere, followed by cooling. The metal paste material is arranged so as to have a finish that is exposed around the metal member on the silicon nitride member of the product bonded body, and the bonded body has a shear strength after thermal shock of 5 kg / mm ² or more. An object of the present invention is to provide a method for manufacturing a bonded body of silicon nitride and a metal, which is a feature.

In the above-mentioned joined body and the method for producing the same, an active metal paste was used, and substantially 60 to 95% by weight of silver, 3 to 39% by weight of copper and 4 to 10% by weight of titanium were blended so as to be 100% by weight in total. 80 to 90 parts by weight of metal powder and vehicle 10 to 20
It is preferable to use a paste brazing material having a composition of 100 parts by weight in total.

[Operation] The reason why the thermal shock resistance of the joined body manufactured by the method of the present invention is improved by the formation of the above-described fillet portion has not been sufficiently elucidated yet, but due to the presence of the formed fillet portion,
Instead of the stress generated due to the difference in thermal expansion between the metal member and the silicon nitride member acting intensively on the surface of the silicon nitride member corresponding directly below the outer peripheral line of the metal member, these stresses are formed on a wide surface in contact with the silicon nitride and the fillet. It is considered that the stress is dispersed because the stress changes into a stress that causes the surfaces to slide with each other, and the horizontal stress generated in the vertical cross section of the silicon nitride member at a position immediately below the metal member edge (peripheral line) is reduced. .

Preferred examples of the active metal paste brazing material used in the method of the present invention are as described above. In this case, the present inventors have found that the titanium content has a great effect on the joining between the silicon nitride member and the metal member. Confirmed by experiments. That is, the amount of titanium is 4% by weight based on the weight of the metal powder.
If it is less than 3, the brazing material will solidify and shrink at the time of joining, or voids will occur in the brazing material due to the high diffusion speed of silver in the brazing material to copper. On the other hand, when the amount of titanium exceeds 10% by weight, the reaction between silicon nitride and titanium in the brazing material excessively proceeds, and the reaction layer becomes unfavorable. Therefore, the preferable addition amount of titanium in the production method of the present invention is 4 to 10% by weight.

In order to form a fillet according to the method of the present invention, two points should be noted.

First, the bonding process must be performed in a vacuum or non-oxidizing atmosphere. The reason is that the metal paste material is applied so as to protrude around the metal member for the purpose of forming the fillet portion, so that there is oxidation of titanium that contributes to the reaction with the paste material, especially silicon nitride, when heated. Because it does not become. If the titanium oxidizes, the paste does not react with the silicon nitride and does not serve the fillet. In particular, the selection of the atmosphere is important because the paste material to be the fillet portion is in contact with the atmosphere before heating and is more easily oxidized than the paste material sandwiched between the silicon nitride member and the metal member.

Second, it must be placed in a vacuum or non-oxidizing atmosphere during cooling. This is because even at the time of cooling, if the temperature is high, titanium is oxidized and a good bonding interface cannot be obtained. On the other hand, it has been confirmed that the cooling rate needs to be appropriately selected depending on the size of the joined body, but does not need to be strictly specified.

 Next, the present invention will be described in detail based on examples.

Example FIG. 1 is a view showing the structure of a joined body manufactured by the method of the present invention (FIG. 1 (a) is a plan view, and FIG. 1 (b) is a cross-sectional view). Will be explained.

A copper disk having a diameter of 10 mm and a thickness of 1 mm was prepared as a metal member. Titanium 2, 4, 6, 8 as an active metal paste material
90 parts by weight of four kinds of metal mixed powders having a composition of 92 to 86% by weight and 6% by weight, respectively, and 10 parts by weight of a vehicle. Using this roll mill, the mixture was kneaded to prepare a paste-like mixture that could be screen printed. 14mm × as silicon nitride member 1
Twenty rectangular silicon nitride plates of 16 mm × 5 mm (thickness) were prepared.

Then, one side of the silicon nitride plate was screen-printed to a diameter of 1
Five each of the above four kinds of paste brazing materials were printed in a 2.0 mm circle. Then, the center of the circular copper plate 2 was overlapped thereon so as to coincide with the center of the paste brazing material 3 printed thereon, and the fillet portion 4 was adjusted and arranged so as to be 1.0 mm, and then joined in a heat treatment furnace. . The furnace used for the joining was a resistance heating type vacuum heating furnace having an oil diffusion pump, and heating, temperature holding and cooling were performed in a vacuum of 1 × 10 ⁻⁴ Torr or less.

Furnace and temperature conditions were to raise the temperature to 600 ° C at 10 ° C / minute, hold at this temperature for 30 minutes, then raise the temperature to 970 ° C at 5 ° C / minute and hold for 40 minutes, then room temperature at 5 ° C / minute. After cooling, the joined body shown in FIGS. 1A and 1B was taken out.

Further, a normal silver solder (BAg-
8) The steel sheets were overlapped and joined at 85 ° C (set temperature of the furnace).

First, measure the shear strength of the joined body before subjecting it to the thermal shock test. Then, hold the joined body in an oven (atmosphere) preheated to 250 ° C for 15 minutes. After 30 cycles of thermal shock treatment as one cycle, the shear strength was measured, and the thermal shock resistance was repeatedly evaluated as compared to before applying thermal shock.

FIG. 2 shows the relationship between the shear strength and the amount of titanium before being subjected to the thermal shock test.
The value was ² kg / mm ² , and the highest value was about 14 kg / mm ² . As the amount of titanium increased to 4, 6, and 8% by weight, the minimum value of the shear strength also increased to about 5 kg / mm ² , 7 kg / mm ² , and 10 kg / mm ² , but the maximum value was about 14 kg / mm ^2. It was mm ^2. As a result, when the titanium content was 2% by weight, the variation in the shear strength was about 12 kg / mm ^2, and it was found that the joining state was considerably different depending on the sample, and it was not suitable for a part requiring reliability. On the other hand, it was found that a bonded body having a titanium content of 4% by weight or more can stably obtain a bonded body having a shear strength of 5 kg / mm ² or more, and can produce a practically reliable portion.

Similarly, the shear strength after the thermal shock test is shown in FIG. 3. From this figure, a decrease in the strength was not confirmed, and it was confirmed that the thermal shock resistance was high, indicating that there was no practical problem.

Further, by using an active metal paste brazing material having a high melting point composition which is largely deviated from the eutectic of silver-copper as in the present embodiment, the joined body and other metal members can be connected to a normal silver brazing material (for example, BAg). It was also found that -8) can be added later.

[Effects of the Invention] As described above, according to the method of the present invention, when obtaining a joined body with a metal member using a silicon nitride member as the non-oxide ceramic, the titanium content is 4 to 10% by weight. By using an active metal paste brazing material and providing a fillet portion of the paste material protruding from the edge of the metal member to a predetermined width or more, a joined body having excellent repeated thermal shock resistance after joining and high strength with little variation Therefore, it is possible to provide a joined body having high reliability as an electronic component or other components.

[Brief description of the drawings]

FIG. 1 is a view showing the structure of a joined body manufactured according to an embodiment, wherein FIG. 1 (a) is a plan view and FIG. 1 (b) is a sectional view. FIG. 2 is a graph showing the relationship between the shear strength before the thermal shock test and the amount of titanium of the joined body manufactured according to the example. FIG. 3 is a graph showing the relationship between the shear strength after the thermal shock test and the amount of titanium of the joined body manufactured according to the example. DESCRIPTION OF SYMBOLS 1 silicon nitride member 2 copper plate 3 active metal paste brazing material 4 fillet portion

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kenji Ichiya 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Dowa Mining Co., Ltd. (56) References JP-A-63-251127 (JP, A) JP-A Sho 60-200868 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 37/02

Claims (2)

(57) [Claims] 1. A joined body comprising a silicon nitride member and a copper or copper alloy metal member joined to each other via a fired active metal paste layer, wherein the area of the silicon nitride member at the joint surface is At least one size larger than the area of the metal member, a fillet surrounding the metal member with a band width of at least 0.25 mm or more around the metal member outer peripheral line and the silicon nitride member surface at the bonding surface is formed by the firing paste. A bonded body of silicon nitride and a metal, which is formed and has a shear strength after thermal shock of 5 kg / mm ² or more. 2. A silicon nitride member and a metal member of copper or a copper alloy, substantially screen-printed silver of 60 to 95% by weight, copper of 3 to 38% by weight, and titanium of 4 to 10% by weight in total of 100% by weight. 80 to 90 parts by weight of a metal powder and 10 to 20 parts by weight of a vehicle are arranged in contact with each other via an active metal paste material having a composition of 100 parts by weight.
Heating the component in a substantially vacuum or non-oxidizing atmosphere followed by cooling, and in the arrangement, the fillet formed by the metal paste protruding from the edge of the metal member has a band of 0.25 mm or more. wide, by placing a metal paste material so that the finished present exposed silicon nitride around the metal member member of product assembly, shear strength after thermal shock to 5 kg / mm ² or more conjugates A method for producing a bonded body of silicon nitride and a metal, characterized by comprising: