JP2501835B2 - Metallic adhesive material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a metallic adhesive material suitable for joining metal to metal, metal to ceramic, and ceramic to ceramic.

(Prior Art) Conventionally, various joining methods are known as a joining method between the same materials such as a metal and a metal or a ceramic and a ceramic, or a joining method between different materials of a metal and a ceramic.

For example, there are fusion welding methods such as electric welding, gas welding, friction welding and the like as a method of joining metals, and there are a brazing method and an adhesion method using an organic adhesive as a method of not melting the base material.

Further, as a joining method of ceramic and ceramic, there are an adhesion method using an organic adhesive and a heat-resistant metal method (see JP-A-61-58870).

For joining between these same materials, as joining methods between different materials of metal and ceramic, there are an adhesive method using an organic adhesive, an active metal method, a shrink fit method, a solid phase reaction method, and the like.
In addition, there is a heat-resistant metal method in which a ceramic substrate is metalized with Mo or W and then nickel-plated, and then soldered to a metal substrate. A recent technology uses an oxide-based inorganic adhesive to remove hydrated compounds. Bonding methods using chemical reactions such as building have also emerged.

(Problems to be Solved by the Invention) However, all of the above-mentioned various joining methods, except for the fusion welding method, which is a unique joining method between metals, are disadvantageous in that they are all weak to heat and have insufficient adhesive strength. .

On the other hand, bonding techniques such as vapor deposition, sputtering, and thermal spraying and bonding techniques using a foil-shaped insert material have also been proposed, but not only have the disadvantage of poor adhesion, but also have a limited range of use. Therefore, it cannot be said that the bonding method is poor in practicality and satisfactory in economical efficiency.

Therefore, as an adhesive material that can eliminate these drawbacks,
The present applicant previously proposed a metallic adhesive material in Japanese Patent Application No. 61-150003. This adhesive material is Cu or Ni and Ti, Zr or Nb
It is a metallic adhesive material composed of a composite powder in which each of these components is mechanically intermeshed with Ag and Ag as constituent components, and has a particularly high adhesive strength, and various metals, ceramics of the same material or different materials Suitable for joining.

However, this metallic adhesive material is particularly applied to a member that repeats thermal cycles, for example, when a heat dissipation substrate in which a copper foil is attached to an alumina substrate is used in a high power power module, or a power transmission component or an automobile. When the operating environment temperature of parts fluctuates from below zero to near 100 ° C, repeated thermal cycles deteriorate the bonding strength and cause peeling.

The present invention was made in order to solve the problems of the metallic adhesive material according to the above proposal, and has heat resistance,
It has high adhesive strength and little deterioration in adhesive strength due to thermal cycle, and it can be easily used not only for joining metal and ceramics of the same material, but also for joining metal and ceramics of different materials. The object of the present invention is to provide a novel metallic adhesive material that satisfies the economical requirements.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present inventor firstly, when applying the previously proposed metallic adhesive material, regarding the mechanism leading to peeling due to deterioration of adhesive force due to a cooling / heating cycle. Tried to analyze. As a result, it was found that the exfoliation occurs in the diffusion layer, that is, the reaction layer of the active metal (Ti, Nb, Zr) and the ceramic.

Therefore, as a result of various studies on measures to prevent such peeling, basically, the thickness of the diffusion layer was reduced to
It has been found that it suffices if the metal plate and the ceramic plate are directly joined via the diffusion layer. However, the thickness of the diffusion layer is dominated by the amount of active metal, and if the amount of active metal is reduced, the bonding force also decreases. However, as a result of further research from another viewpoint in order to solve this problem, the present inventor has found that the problem can be solved by making the particle size of the active metal as small as possible and facilitating the diffusion. That is, it was found that if the particle size of the active metal is made small to facilitate diffusion, a strong binding force can be exhibited even if the diffusion layer is thin, and at that time, by making the particle size fine, the amount of the active metal component can be increased at the same time. It has been found that a strong binding force can be exhibited even if the amount is reduced, and the present invention is made here.

That is, the metallic adhesive material according to the present invention, Cu and Ni
10 to 60% of at least one of them, 0.5 to 10% of at least one of Ti, Nb and Zr, with the balance being Ag and inevitable impurities, and each component is mechanical Particle size 5μ mechanically meshed by alloy method
It is characterized by being substantially composed of a composite powder of m or less, and is characterized in that the powder is formed into a sheet or a paste.

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

FIG. 1 is a diagram showing a component system and a composition system (wt%) of the metallic adhesive material of the present invention, wherein the A component comprises at least one of Cu and Ni, and the B component comprises Ti, Nb and Zr. In the system consisting of at least one of the above and the balance being the C component consisting essentially of Ag, the A component: 10 to 60%, the B component: 0.
5 to 10%, C component: The remaining shaded area in the figure is a composition range in which desired performance as an adhesive material can be exhibited, and peeling due to deterioration in bonding strength due to a cooling / heating cycle can be prevented.
If the amount of A component is less than 10% or more than 60%, the adhesive force is not obtained, which is not preferable. On the other hand, if the content of the component B exceeds 10%, the thermal shock resistance decreases, while if it is less than 0.5%, the activity is insufficient and diffusion bonding becomes poor, which is not preferable.

The metallic adhesive material having the above chemical components needs to be manufactured by a so-called mechanical alloy method. For that purpose, the metal powder of each component is mechanically interlocked by mechanically interlocking each component by mixing and stirring for a required time under high speed and high energy using a stirrer such as a crusher, a ball mill or an attritor. It is possible to obtain a so-called mechanical alloy type composite powder.

When such a composite powder is used, the joining strength can be significantly improved if the joining temperature is appropriately selected. This is because, as shown in FIG. 2, the fine powder of each component is mechanically meshed and bonded, so that the fine powder of each component closely adjacent at the bonding temperature is melted on the surface and the bonding between the particles becomes strong, This is considered to serve as a kind of glue and increase the bonding strength. Incidentally, such an appropriate bonding temperature (in the Ag-Cu system)
When used in a state where each component was alloyed at a high temperature exceeding 800-900 ℃), the effect was observed to decrease. In the simple mixed state, the above effects could not be expected even when heated because each component was in a separated mixed state.

However, the particle size of such a composite powder needs to be 5 μm or less (a mesh of 5 μm is all-passed) to enhance the activity. In this respect, according to the applicant's previous proposal, the particle size of the composite powder is 44 μm or less, preferably
Although it is set to 10 μm or less, it is different from the present invention because it specifically discloses only a composite powder having a particle size in the vicinity of at least 10 μm.

FIG. 3 shows a metallic adhesive material composed of a composite powder obtained by adding Ti powder of various particle sizes and contents to a Cu-Ag system,
An example of the results of investigating the relationship between the number of possible cycles and Ti content in the thermal cycle test (-55 ° C x 30 min to 150 ° C x 30 min) when joining Al ₂ O ₃ -Cu substrate combinations Is shown.

From the figure, it can be seen that as the grain size of the Ti powder becomes finer, it becomes possible to bond even a small amount of Ti, and the smaller the amount of Ti, the higher the strength. However, the active metal (Ti) is 0.5
If it is less than%, it is not activated, resulting in poor bonding. The activation is affected by the firing (bonding) atmosphere, and the activation is easier under vacuum than in the N ₂ atmosphere.

As is clear from this test result, in the present invention, the particle size of the composite powder is regulated to 5 μm or less. If the particle size of the composite powder is made smaller than 5 μm,
A strong joining force can be obtained with a small amount of active metals (Ti, Zr, Nb), and deterioration of the joining force can be made extremely small, especially even in the thermal cycle.

In order to obtain a composite powder having the above particle size, a fine powder of 10 μm or less may be used as a raw material for mechanical alloying. Further, it is preferable that the composite powder occupy 80% or more of the whole metallic adhesive material, and there is no problem even if some component powders such as Cu, Ag and Ti powders are mixed.

The metallic adhesive material consisting essentially of such a composite powder can be used in various forms, such as powder, sheet (compacted powder compact, powder compact), and paste. In addition,
In use, when Ti is contained, it is preferable to use it at a predetermined temperature in consideration of oxidation in air at the time of heating and joining.

For example, in the case of a powdery metallic adhesive material, as a preferable usage mode, first, a thin frame is set on a substrate such as metal or ceramic, and then the adhesive material powder is filled and the adhesive surface is sandwiched. , Then in a non-oxidizing atmosphere or 10 ^-3
600-under a load of 1-100 kg / cm ² under reduced pressure of Torr or less
Heat to 900 ° C for the required time and join. It should be noted that heat treatment at a temperature above 900 ° C. alloys the adhesive material and reduces the bonding effect.

In addition, as a preferred mode of use as an insert material, a powder compact or a powder rolling compact is sandwiched between base materials to be bonded, or a paste is printed on one surface of the base materials to be bonded. After drying and drying, the binder component is degreased at around 600 ° C. in an inert atmosphere, and bonding is performed when the degreased film thickness is at least 10 μm or more. Note that if degreasing is performed at a high temperature of 600 ° C or higher, bonding will not be possible. In either case the junction aspect, the bonding conditions, 0.5~10kg / cm 750~950 ℃ ² of a load at 10 ^-3 Torr or less under a reduced pressure or in an inert atmosphere while applying, preferably 83
Heat bonding at a temperature of 0 to 930 ° C. If the heating temperature is a high temperature of 950 ° C or less, a welding phenomenon occurs, and if the heating temperature is 750 ° C or less, joining becomes insufficient.

(Example) Next, the Example of this invention is shown.

Example 1 Various metal powders shown in Table 1 were classified in an N ₂ stream to obtain 10 μm.
After the powder having a particle size of m or less, it was blended in a ratio shown in the same table and mixed and pulverized in an attritor ball mill for 7 hours to obtain a composite powder. The obtained composite powder was 5 μm or less, and the Fisher average particle size was 2.1 to 3.2 μm. Microscopic observation of this composite powder revealed that it was in the form of a mechanical alloy in which each component particle was mechanically meshed and bonded.

Next, on the alumina substrate of 50 × 50mm □ × 1.2mmt, the thickness
A 0.4 mm rubber frame was placed on the frame for edging, the composite powder was filled in the frame, and a copper plate of the same size and a thickness of 0.3 mm was placed on the frame, and the alumina substrate and the copper plate were heat-bonded. In addition,
For heat bonding, apply a load of ² kg / cm ² and under a reduced pressure of 10 ^-4 Torr,
The heating was performed at 00 ° C. for 1 hour.

A bonding test and a thermal cycle test were carried out on the composite substrate thus manufactured. The results are shown in the same table.

In addition, in the bonding test, tensile rods were adhered to both surfaces of the composite substrate, and both ends were pulled by a tensile tester to reach destruction. At this time, what was broken in the alumina plate layer was judged to be good adhesion, and what was broken in the adhesive material layer was judged to be defective bonding.

The thermal cycle test is -55 ° C x 30 minutes and 150 ° C x 3 minutes.
Holding for 0 minutes was set as one cycle, and after each cycle, a tensile test was performed to check the presence or absence of breakage, and the number of cycles until the breakage was evaluated.

As comparative examples, those having a composition outside the scope of the present invention and those having a coarse particle size of the composite powder were given and the same test was conducted.
The results are also shown in the table.

As is clear from Table 1, in the case of the examples of the present invention using the adhesive material having the chemical components and the composite powder within the scope of the present invention, the bonding state is good and the number of cooling / heating cycles is high. On the other hand, in Comparative Example No. 11 having an excessively large composite powder particle size and Comparative Examples No. 13 and No. 14 having an excessively large amount of B component, even if the bonding state is good, the number of cooling / heating cycles is extremely small, and B In Comparative Example No. 12 in which the component amounts were insufficient, joining itself was impossible.

Example 2 The composite powders obtained in No. 1, No. 3 and No. 5 of Example 1 were pressed at 50 kgf / mm ² using a powder compacting machine to obtain 30 mm □ × 2 mmt.
Was molded into a coin shape.

Then, it was heated and sintered in a hydrogen stream at 710 to 720 ° C. for 1.5 hours. This sintered body was repeatedly annealed and rolled three times to obtain a sheet having a thickness of 0.2 mm. A 50 mm □ insert material was cut out from this sheet.

Next, the same alumina substrate and copper plate as in Example 1 were prepared, and this sheet-shaped insert material was sandwiched between the two, and
^At a reduced pressure of ^-3 Torr, apply a load of ² kg / cm ² and 750 ℃
It was heated for 30 minutes to obtain a composite substrate. The bonding test and the thermal cycle test similar to those in Example 1 were performed on the obtained composite substrate. The results are shown in Table 2.

As is clear from Table 2, in any of the examples, since the chemical components and the composite powder within the scope of the present invention are included, the bonded state is good, and the number of cooling / heating cycles is high.

Example 3 The composite powders obtained in No. 1 to No. 10 of Example 1 were blended in the following proportions and kneaded with a three-roll mill to give a paste.

Mixing ratio: 24 parts by weight of composite powder Ethyl cellulose 4.4 〃 Texanol 5 〃 Surfactant 0.5 〃 Next, prepare a 50 mm × 50 mm × 1.5 mmt alumina substrate as a ceramic substrate and a 50 mm × 50 mm × 0.3 mmt copper plate as a metal plate, The above paste was printed on the surface of a copper plate to a thickness of 30 μm using a screen printing method. The screen used is stainless steel 200 mesh, biased and has an emulsion thickness of 45 μm.

After printing, level at room temperature for 10 minutes and continue to 105 ℃
And dried for 30 minutes. After drying, a thick film firing furnace was used to degrease by heating to 600 ° C. in a nitrogen atmosphere.

After stacking the alumina substrate on the degreased substrate,
A load of 10 kg / cm ² was applied, heating was performed at 850 ° C. for 15 minutes in a N ₂ gas stream or a reduced pressure atmosphere of 10 ⁻⁴ Torr, and bonded to obtain a composite substrate.

The bonding test and the thermal cycle test similar to those in Example 1 were performed on the obtained composite substrate. The results are shown in Table 3.

As is clear from Table 3, in each of the examples, since the chemical components and the composite powder within the scope of the present invention are included, the bonded state is good and the number of cooling / heating cycles is high.

In each of the above embodiments, an example of an alumina substrate and a copper plate was shown as a combination of substrates, but ceramics of other materials,
It goes without saying that different materials of metals or combinations of the same materials can be used similarly.

(Effects of the Invention) As described in detail above, the metallic adhesive material according to the present invention has a chemical composition adjusted by a specific component system, a powder form is a composite powder, and the composite powder is a fine particle having a particle size of 5 μm or less. Since the grain size is adopted, not only a joined portion that is easy to join and has excellent heat resistance and joining strength can be obtained, but also an excellent effect that the joining force is less deteriorated particularly in a cooling / heating cycle can be obtained. Moreover, it can be used not only for joining metals and ceramics of the same material but also for joining different materials.

[Brief description of drawings]

FIG. 1 is a diagram showing a component system and a composition range of the metallic adhesive material according to the present invention, FIG. 2 is an explanatory diagram showing a powder form of the metallic adhesive material according to the present invention, and FIG. It is a figure which shows the Ti content in a metallic adhesive material, and the relationship of the number of cooling / heating cycles.

Claims (3)

(57) [Claims] 1. In weight% (hereinafter the same), at least one of Cu and Ni is contained in an amount of 10 to 60%, at least one of Ti, Nb and Zr is contained in an amount of 0.5 to 10%, and the balance is Ag. And a metallic adhesive material having a composition consisting of unavoidable impurities and consisting essentially of a composite powder having a particle size of 5 μm or less in which each component is mechanically meshed and bonded by a mechanical alloy method. 2. At least one of Cu and Ni is contained in an amount of 10 to 60.
%, At least one of Ti, Nb and Zr is 0.5-10%
A powder consisting of a composite powder having a particle size of 5 μm or less in which the balance is composed of Ag and unavoidable impurities, and each component is mechanically meshed and bonded by a mechanical alloy method is formed into a sheet. A metallic adhesive material characterized by being a thing. 3. At least one of Cu and Ni is contained in an amount of 10 to 60.
%, At least one of Ti, Nb and Zr is 0.5-10%
A powder consisting essentially of a composite powder with a particle size of 5 μm or less, which contains a balance of Ag and unavoidable impurities, and whose components are mechanically meshed and bonded by a mechanical alloy method, is dispersed in an organic solvent. A metallic adhesive material characterized by being formed into a paste.