JPH0574552B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for joining metal and ceramic, and a joining material used in the method.

[Conventional technology] Conventionally, Ti-Cu eutectic alloys and Ag-Cu alloys have been used as brazing materials in active metal bonding between metals and ceramics.
An alloy containing several weight percent of Ti, Zr, V, etc. is used.

For example, in Japanese Patent Application Laid-Open No. 178476/1983, titanium and copper foil are laminated, or a brazing filler metal mixed with copper powder is interposed between the metal and ceramic, and approximately 900
A method of bonding by heating to .degree. C. is disclosed.

In addition, Japanese Patent Application Laid-open No. 123499/1983 describes AlN and Si ₃
A method of bonding a nitride ceramic such as N ₄ to copper or iron using an Ag--Cu alloy brazing filler metal containing 10% by weight or less of V is disclosed.

Since active metals have strong chemical affinities with oxygen, nitrogen, and carbon, melts of alloys containing them have good wettability with ceramics. However, since these alloys have poor malleability, it is difficult to produce foil-shaped brazing filler metals without using special methods such as rapid solidification. Therefore, as described above, methods have been adopted in which an active metal film is applied to the surface of the brazing material or ceramic by pulverizing the alloy into powder or by using a thin film forming method such as vapor deposition.

Furthermore, JP-A-62-72472 discloses a method for joining metal and ceramic, in which a paste of Ti or Zr powder mixed with a binder is applied to the ceramic surface, and then silver brazing powder is placed and melted by heating. Disclosed.

The metallization method is the most widely used metal-ceramic bonding method other than the active metal method. This method involves metallizing Mn-Mo alloy or W alloy on the ceramic surface, and then plating Ni on top of it.
This Ni plating layer is bonded to metal by brazing, and is often used to bond oxide ceramics and metals. In this case, there are various brazing methods such as silver soldering and soldering.

In metal-ceramic bonding, the bonding temperature has an important meaning; if the temperature is high, the thermal stress of the bond increases, causing problems such as cracking of the ceramic. Therefore, it is better to keep the bonding temperature as low as possible.

[Problems to be Solved by the Invention] However, in the conventional active metal bonding method, bonding must be performed in a high vacuum of 10 ^-5 Torr or less or in a completely inert atmosphere to prevent oxidation. Furthermore, silver solder with a high silver content is expensive, increasing the cost.

Furthermore, the metallization method involves many steps, which is economically problematic, and there is also room for improvement in terms of quality and bonding strength of the metallized surfaces.

Therefore, the first object of the present invention is to provide an active metal bonding material for metal-ceramic bonding that is inexpensive, can be used in low vacuum, and generates less thermal stress; The object of the present invention is to provide a metal-ceramic bonding method using this active metal bonding material.

[Means for Solving the Problems] That is, the present invention includes a method for joining metal and ceramic and a joining material described below: 5 to 20% by weight of titanium, and the balance being tin, lead,
A brazing material for metal-ceramic bonding, which is composed of two or more components selected from the group consisting of silver and bismuth, and has a silver content of 3.5% by weight or less;
Paste for metal-ceramic bonding consisting of 85 to 95 parts of overlap and 5 to 15 parts by weight of organic flux; In the method for bonding metal and ceramic, the brazing material for metal-ceramic bonding described in , or the paste for metal-ceramic bonding described in . A method for joining metal and ceramic, characterized in that the metal and ceramic are joined by interposing the metal and the ceramic between the metal and the ceramic, and heating the metal to the ceramic above the melting point of the brazing filler metal or paste under a reduced pressure of 0.5 torr or less; In the bonding method, the brazing material for metal-ceramic bonding described in 2 or the paste for metal-ceramic bonding described in 2 is interposed between the metal and the ceramic, and the partial pressure of oxygen or nitrogen corresponding to a reduced pressure of 0.5 Torr or less is applied. A method for joining metal and ceramic, characterized in that the metal and ceramic are joined by heating above the melting point of the brazing filler metal or paste in an inert atmosphere; In the method for joining metal and ceramic, metallic titanium is added to the joining surface of the ceramic. Coated with titanium or titanium hydride in an equivalent amount of 5 to 20% by weight,
Between the coated surface of the ceramic and the metal, two or more types selected from the group consisting of titanium or titanium hydride in terms of titanium metal and 80 to 95% by weight of the total amount of the brazing filler metal are selected from the group consisting of tin, lead, silver, and bismuth. A brazing filler metal for metal-ceramic bonding having a silver content of 3.5% by weight or less in terms of brazing filler metal, or a brazing filler metal for bonding metal-ceramic bonding consisting of 85 to 95 parts by weight and 5 to 15 parts by weight of an organic flux. Interpose metal-ceramic bonding paste,
A method for joining metal and ceramic, characterized in that the metal and ceramic are joined by heating above the reaction temperature of titanium and brazing filler metal or paste under reduced pressure of 0.5 torr or less; Coating the joint surface with 5 to 20% by weight of titanium or titanium hydride in terms of titanium metal,
Between the coated surface of the ceramic and the metal, two or more types selected from the group consisting of titanium or titanium hydride in terms of titanium metal and 80 to 95% by weight of the total amount of the brazing filler metal are selected from the group consisting of tin, lead, silver, and bismuth. , and the silver content is equivalent to the amount of brazing filler metal.
A brazing filler metal for metal-ceramic bonding or a brazing filler metal for metal-ceramic bonding having a content of 3.5% by weight or less
Titanium and brazing filler metal or A method for joining metal and ceramic, characterized in that the metal and ceramic are joined by heating to a temperature higher than the reaction temperature of the paste.

[Function] The present invention uses a brazing filler metal whose active metal component is titanium and whose other brazing filler metal components are two or more components selected from the group consisting of tin, lead, silver, and bismuth. This method involves heating and bonding metal and ceramic in a low vacuum.

The brazing filler metal for metal-ceramic bonding of the present invention is 5 to 20
% by weight of titanium, and the balance is composed of two or more components selected from the group consisting of tin, lead, silver, and bismuth, and the content of silver is 3.5% by weight or less.

The brazing material of the present invention contains titanium as an essential component. As titanium, metallic titanium or titanium hydride can be used. When using titanium hydride, it may be used in an amount within the above-mentioned range in terms of titanium metal. The brazing filler metal may be a powder mixture of titanium or titanium hydride powder and the above-mentioned metal components, or a mixture of titanium or titanium hydride powder and alloy powder of other components; It can also be in the form of a paste made by kneading a mixture or alloy powder with a resin or organic solvent.
Further, it may be a foil-shaped brazing material made by melting all the components and using a rapid solidification method, and the form of the brazing material is not limited. Two or more of the brazing filler metal components other than titanium or titanium hydride, such as tin, lead, silver, and bismuth, can be combined in any amount within a practical range.

In the method of the present invention, tin, lead,
A brazing filler metal consisting of two or more components selected from the group consisting of silver and bismuth can also be used, and this brazing filler metal should be used when the bonding surface of the ceramic is coated with titanium or titanium hydride. (Hereinafter, this brazing material will be referred to as the second brazing material). If the second brazing filler metal is used in an amount such that the composition of the melt obtained by heating it together with the coated titanium or titanium hydride is similar to the composition of the brazing filler metal of the present invention described above, the metal and ceramic can be combined. can be firmly joined. here,
The content of silver in the second brazing filler metal is less than 3.5% by weight of the total amount of titanium metal and brazing filler metal. Note that the second brazing filler metal may be in the form of a powder mixture, an alloy powder, or even a paste like the brazing filler metal of the present invention.

The brazing filler metal of the present invention or the second brazing filler metal containing the ingredients in the above-mentioned range is interposed between the ceramic member and the metal and heated at a temperature higher than the melting point of the brazing filler metal or paste under reduced pressure of 0.5 torr or less or titanium and the second brazing filler metal. 2
The ceramic member and the metal can be joined by heating to a temperature higher than the reaction temperature of the brazing material or the paste containing the second brazing material.

Furthermore, as in the case of using a second brazing filler metal, if the composition of the melt obtained by heating to a temperature equal to or higher than the reaction temperature of titanium and the second brazing filler metal is the same as that of the brazing filler metal of the present invention, it is not necessarily the case that the soldering filler metal is genuine. It is not necessary to homogeneously mix or alloy all the components containing titanium in advance as in the invention brazing material, but a predetermined amount of titanium can be coated on the ceramic surface by means such as vapor deposition or coating, and then combined with the second brazing material component. It can also be melted.

When using the brazing filler metal for metal-ceramic bonding of the present invention, which uses titanium or titanium hydride (active metal) in combination with other brazing filler metal components (tin, lead, silver and/or bismuth), titanium or titanium The brazing material components excluding the hydride (hereinafter referred to as the brazing material master alloy) are first melted, and the titanium or titanium hydride is dissolved therein to form a molten active metal alloy.

In the case of conventional brazing filler metals, the melting point of the brazing filler metal mother alloy is relatively high and there is little difference from the melting point of the active metal.
If the active metal powder or foil is exposed to a direct atmosphere at a temperature below the melting point of the filler metal, it will take a considerable amount of time to become incorporated into the filler metal master alloy, resulting in a longer exposure time to the direct atmosphere of the active metal powder or foil at temperatures below the melting point of the filler metal master alloy. If oxygen or nitrogen is contained in the atmosphere, oxidation or nitridation tends to occur, and the active metal that has undergone oxidation or nitridation will not be alloyed even if the brazing material mother alloy is melted. For example, in the conventionally used Ag-Cu-Ti brazing filler metal, the Ag-Cu brazing filler metal mother alloy is first melted,
Ti is dissolved in this. The melting point of the Ag-Cu base alloy is 600 to 800°C depending on the composition, and within this range, those with melting points of 750 to 800°C are often used. In the case of Cu-Ti eutectic brazing filler metal, the process until the eutectic reaction occurs at 872°C is the same.

On the other hand, in the brazing material of the present invention, since the brazing material mother alloy is composed of two or more selected from the group consisting of tin, lead, silver, and bismuth, its melting point is Ag-Cu.
The temperature is several hundred degrees Celsius or more lower than that of the parent alloy. For this reason, the powder of titanium or titanium hydride is taken into the brazing material matrix alloy at a very early stage of heating, and contact with the atmosphere is cut off. Next, as the heating temperature increases, the active metal or its hydride melts into the mother alloy, and when all the components are dissolved, a state becomes effective for bonding ceramic and metal.
Here, the oxidation and nitridation of active metals naturally occur more violently at higher temperatures, so the brazing filler metal with the composition of the present invention that cuts off contact with the atmosphere of active metals from low-temperature regions is effective in preventing oxidation and nitridation. It's advantageous.

Furthermore, it is more effective to use titanium hydride than metallic titanium to block contact of the active metal with the atmosphere. This is because when titanium hydride is heated under reduced pressure, it decomposes at a temperature of approximately 400-500°C and releases hydrogen gas. As a result, the bonding gap becomes a reducing atmosphere enriched with hydrogen, which is effective in preventing oxidation and nitridation of titanium.

Another effective method is to use a low melting point flux. If a simple soldering flux is interposed in the gap together with the brazing material, the flux will melt and fill the gap before the brazing material melts, cutting off contact between the brazing material and the atmosphere. When heated in a reduced pressure, the flux evaporates and forms a reducing atmosphere gas, but when heated in an inert gas, the brazing filler metal master alloy melts before the flux reaches its boiling point, forming active metals or Protects the hydride from oxidation and nitridation. The flux may be something simple, such as pine resin, but it is more preferable to use a mixture of a modified resin dissolved in an organic solvent and a thickener mixed therein.
It is practical to use a paste-like brazing material obtained by kneading the brazing material powder and the flux. Although it is not an essential component of flux, using a paste containing a small amount of a halide activator has the effect of cleaning the bonding surface, so even more effective atmosphere isolation can be expected.

Furthermore, when using a second brazing filler metal, if titanium is coated on the ceramic surface in advance, this titanium-coated surface is coated with the second brazing filler metal or the second brazing filler metal.
If the titanium surface is coated with a paste containing a brazing material component, the titanium surface can be shielded from the atmosphere.

As mentioned above, in order to prevent oxidation and nitridation of the active metal (titanium) in the brazing filler metal of the present invention, Sn-Pb series, Sn-Ag series, and Sn, which have significantly lower melting points than conventional brazing filler metals, are used as the brazing filler metal mother alloy. -Bi series, Sn-Pb-
A brazing material master alloy made of two or more components selected from the group consisting of tin, lead, silver, and bismuth, such as Ag-based and Sn-Pb-Bi-based materials, is used. The present invention also includes a brazing material in which titanium hydride is used instead of metallic titanium in order to more effectively isolate the active metal from the atmosphere, and a paste-like brazing material in which flux is kneaded with the brazing material.

When joining metal and ceramic using such a brazing filler metal, there is no need for a high vacuum of less than 10 ^-5 Torr or an H ₂ reducing atmosphere, unlike the conventional active metal method.
A strong bond between metal and ceramic can be obtained by heating the filler metal to a temperature above its melting point (generally above 800°C) in a low vacuum of less than ×10 ^-1 Torr or in an inert atmosphere. In actual joining work, there are many joining methods depending on the form of the brazing material and the method of application, but the soldering material of the present invention is used in a low vacuum of 5 x 10 ^-1 Torr or less. The metal-ceramic bonding method is included in the present invention regardless of its embodiment. Generally, a mixed powder of titanium or titanium hydride powder and brazing material master alloy powder, or a paste made by kneading this with organic flux, is interposed between the metal and ceramic in a vacuum of 5 x 10 ^-1 Torr or less. Bonding is performed by heating above the melting point of the brazing filler metal, but instead of the brazing filler metal mother alloy powder, powder of the component metal of the mother alloy can be used, and instead of titanium powder, titanium can be vapor deposited or sputtered on the ceramic surface. It can also be applied in the form of a thin film. In other words, these are merely modifications of the embodiment for forming the brazing material component of the present invention at or near the bonding temperature, and are included within the scope of the present invention.

To further explain the bonding atmosphere, the atmosphere is 5×
10 ^-1 torr or less, preferably 1 x 10 ^-1 torr or less, or a corresponding oxygen or nitrogen partial pressure, and the heating temperature is above the melting point of the brazing material (generally 800 ~1000°C, preferably 900°C or higher).

Note that the amount of titanium in the brazing filler metal of the present invention or the amount of titanium in the melt when using the second brazing filler metal is 5% by weight.
If it is less than that, the effect of active metal addition is insufficient,
Additionally, if the content exceeds 20% by weight, the melting point of the brazing filler metal will increase, which may limit the types of metals to be joined.
This is not preferable because it increases thermal stress.

Additionally, if the oxygen partial pressure in the atmosphere exceeds 1×10 ^-1 Torr (corresponding to air pressure of 5×10 ^-1 Torr), the bonding will be incomplete due to oxidation of the active metal, so the oxygen partial pressure should be increased. It must be under reduced pressure of less than 1 x 10 ^-1 Torr, preferably less than 2 x 10 ^-2 Torr, or under an inert atmosphere.

When flux is used to more effectively prevent oxidation and nitridation of active metals, the blending ratio of flux is preferably 5 to 15 parts by weight based on the total amount. When the blending ratio is less than 5 parts by weight, it is difficult to form a paste, and when it exceeds 15 parts by weight, the brazing filler metal component becomes too small and voids are likely to be formed at the bonding surface.

[Example] The present invention will be further explained with reference to Examples below.

Example 1 90 parts by weight of Sn63 weight %-Pb 37 weight % alloy powder with an average particle size of 5 μm and titanium powder with an average particle size of 3 μm were placed between a 0.3 mm thick copper plate and a 0.635 mm thick alumina.
Evenly sandwich a mixed powder consisting of 10 parts by weight.
It was heated to 900° C. for 15 minutes in a vacuum of 0.1 Torr, cooled, and then taken out.

It was confirmed that the copper plate and alumina were firmly bonded and there were no voids.

Example 2 A copper plate and alumina were joined in the same manner as in Example 1. However, instead of Sn-Pb alloy powder, Sn96.5
Weight % - Using powder with Ag3.5 weight %, organic flux consisting of resin and solvent was added to the total powder weight.
A 10% by weight paste was kneaded and applied to the alumina surface. The heating temperature was 950°C.

In this case, as in Example 1, a strong bond without voids was obtained.

Example 3 In the same manner as in Example 1, bonding was carried out in a vacuum of 0.05 Torr using a 5% by weight Sn-93.5% by weight Pb-1.5% by weight Ag alloy powder instead of the Sn--Pb alloy powder.

In this case, as in Example 1, a strong bond without voids was obtained.

Example 4 In the same manner as in Example 2, 90 parts by weight of a mixture of 85 parts by weight of an alloy powder of 46% Sn-46% Pb-8% Bi by weight and 15 parts by weight of titanium hydride powder (14.5 parts by weight in terms of titanium metal) was prepared. was used by kneading it with 10 parts by weight of organic flux. The bonding temperature was 900°C.

In this case, as in Example 1, a strong bond without voids was obtained.

Example 5 In the same manner as in Example 4, 42% by weight Sn-58% by weight Bi alloy powder was used.

In this case, as in Example 1, a strong bond without voids was obtained.

Example 6 In the same manner as in Example 2, titanium hydride was used instead of titanium powder.

In this case, as in Example 1, a strong bond without voids was obtained.

Example 7 Bonding was carried out in the same manner as in Example 1 using titanium hydride powder in a vacuum of 0.05 Torr.

In this case as well, a strong bond with no voids was obtained.

Example 8 Titanium (titanium: 10
A copper plate coated with a paste made by kneading 90 parts by weight of an alloy powder of 63% by weight Sn-37% by weight with an organic flux and 10 parts by weight of an organic flux was combined with alumina deposited with alumina (equivalent to 10% by weight) and a copper plate coated on the surface to be bonded. It was heated to 900℃.

In this case, as in Example 1, a strong bond without voids was obtained.

Example 9 In the same manner as in Example 8, instead of vapor depositing titanium, 15 parts by weight of a paste prepared by kneading 90 parts by weight of titanium powder and 10 parts by weight of an organic flux was applied onto the alumina surface.

In this case, as in Example 1, a strong bond without voids was obtained.

Example 10 Ti, Sn, and Pb powders with an average particle size of 5 μm were each
A paste prepared by mixing 10 parts by weight, 55 parts by weight, and 35 parts by weight and kneading 10% by weight of organic flux was applied to the copper surface and combined with alumina. This was heated to 875℃ in a vacuum of 0.1 Torr for 15 minutes.
They were bonded by heating for a minute.

In this case, as in Example 1, a strong bond without voids was obtained.

Comparative Example 1 Heating was performed in a vacuum of 1 Torr in the same manner as in Example 1, but no bonding occurred.

Comparative Example 2 Bonding was attempted in the same manner as in Example 1 using a mixed powder of 10 parts by weight of titanium powder and 90 parts by weight of 75% Ag-25% Cu alloy powder, but no bonding occurred.

Comparative Example 3 Although the heating temperature was set to 800° C. in the same manner as in Example 2, no bonding occurred.

[Effects of the Invention] As is clear from the above description, the present invention provides a brazing material for metal-ceramic bonding that is inexpensive, does not require high vacuum, and has low thermal stress, and a metal-ceramic bonding method using the same. can do.

Claims (1)

[Claims] 1. 5 to 20% by weight of titanium, the balance being tin, lead,
1. A brazing filler metal for metal-ceramic bonding, comprising two or more components selected from the group consisting of silver and bismuth, and having a silver content of 3.5% by weight or less. 2. A metal-ceramic bonding paste comprising 85 to 95 parts of the brazing material for metal-ceramic bonding according to claim 1 and 5 to 15 parts by weight of an organic flux. 3. In a method for joining metal and ceramic, the brazing material for metal-ceramic joining according to claim 1 or the paste for metal-ceramic joining according to claim 2 is interposed between the metal and ceramic, and the method is performed under reduced pressure of 0.5 Torr or less. 1. A method for joining metal and ceramic, which comprises joining the metal and ceramic by heating the brazing filler metal or paste to a temperature higher than the melting point. 4. In the method for joining metal and ceramic, the brazing material for metal-ceramic joining according to claim 1 or the paste for metal-ceramic joining according to claim 2 is interposed between the metal and ceramic, and the mixture is brought into a reduced pressure state of 0.5 torr or less. A method for joining metal and ceramic, which comprises joining the metal and ceramic by heating the brazing filler metal or paste above the melting point in an inert atmosphere with a corresponding partial pressure of oxygen or nitrogen. 5. In a method for joining metal and ceramic, the joining surface of the ceramic is coated with 5 to 20% by weight of titanium or titanium hydride in terms of titanium metal, and the amount of titanium in terms of titanium metal is coated between the coated surface of the ceramic and the metal. or two or more components selected from the group consisting of tin, lead, silver and bismuth in an amount of 80 to 95% by weight of the total amount of titanium hydride and brazing filler metal,
A metal-ceramic bonding brazing material having a silver content of 3.5% by weight or less or a metal-ceramic bonding paste consisting of 85 to 95 parts by weight of the metal-ceramic bonding brazing material and 5 to 15 parts by weight of an organic flux is interposed. A method for joining metal and ceramic, characterized in that the metal and ceramic are joined by heating above the reaction temperature of titanium and brazing filler metal or paste under reduced pressure of 0.5 Torr or less. 6. In a method for joining metal and ceramic, the joining surface of the ceramic is coated with 5 to 20% by weight of titanium or titanium hydride in terms of titanium metal, and an amount of titanium in terms of titanium metal is coated between the coated surface of the ceramic and the metal. or two or more components selected from the group consisting of tin, lead, silver and bismuth in an amount of 80 to 95% by weight of the total amount of titanium hydride and brazing filler metal,
A brazing filler metal for metal-ceramic bonding having a silver content of 3.5% by weight or less in terms of brazing filler metal, or a metal-ceramic consisting of 85 to 95 parts by weight of the brazing filler metal for metal-ceramic bonding and 5 to 15 parts by weight of an organic flux. The metal and ceramic are bonded by interposing a bonding paste and heating the titanium to a brazing material or paste reaction temperature or higher in an inert atmosphere with a partial pressure of oxygen or nitrogen corresponding to a reduced pressure of 0.5 torr or less. A distinctive method of joining metal and ceramic.