JP7311447B2 - airtight terminal - Google Patents

Description

The present disclosure relates to hermetic terminals.

Conventionally, airtight terminals used in vacuum equipment, nuclear equipment, etc. are coaxial airtight terminals in which a columnar central conductor is provided through a ceramic substrate and a metal ring is fitted around the outer periphery of the ceramic substrate. .

As such an airtight terminal, for example, Patent Document 1 discloses a metal pin, a first ceramic cylindrical body fitted around the pin, and a first ceramic cylindrical body fitted around the outer periphery of the pin. The combined first metal cylindrical body, the second ceramic cylindrical body fitted to the outer periphery of the first metal cylindrical body, and the second ceramic cylindrical body fitted to the outer periphery and a second metal tube joined together, the first ceramic tube being hermetically secured to the pin at a first attachment point as the vacuum side end and the atmospheric side end. A second ceramic body having a relief groove at its other end for the pin and hermetically secured to the first metallic tubular body at a second securing point axially offset from the first securing point; A tubular body is hermetically secured to the first metallic tubular body at a third fastening point axially offset from the first and second fastening points, and forward and rearward of the third fastening point. and is hermetically secured to a second metallic tubular body at a fourth fastening point axially offset from the first, second and third fastening points. It is

Japanese Patent Publication No. 55-2065

However, the metallized layer and the plated layer are sequentially formed from the outermost peripheral surface side of the first ceramic cylindrical body, and the plated layer and the inner peripheral surface of the first metal cylindrical body are brazed from the vacuum side. However, depending on the length of the metallized layer in the axial direction, the brazing material may leak into the escape groove on the atmosphere side, and the first ceramic tubular body and the first metal tubular body may be separated through the escape groove. It was possible to stick with.

If heating and cooling are repeated in this sticking state, there is a problem that residual stress tends to increase and cracks tend to occur in the first ceramic cylindrical body.

An object of the present disclosure is to provide an airtight terminal that can be used for a long period of time because residual stress is less likely to accumulate in ceramics even when heating and cooling are repeated, and as a result, the occurrence of cracks is reduced. aim.

The airtight terminal of the present disclosure includes a columnar or cylindrical conducting member, a first outer peripheral surface, a stepped surface coaxially positioned with the first outer peripheral surface, and a first end of the first outer peripheral surface extending from the conducting member. A disk having a first end surface extending toward the axis, a second end surface extending from the second end of the stepped surface toward the axis of the conducting member, and a first through hole for inserting the conducting member. and a first cylindrical body that surrounds the first ceramic substrate and is bonded to the first outer peripheral surface, wherein the stepped surface starts from the second end and an end point of the first metal layer is located between the first end and the second end.

Further, the airtight terminal of the present disclosure includes a columnar or cylindrical conductive member, a first outer peripheral surface, a first end surface extending from a first end of the first outer peripheral surface toward an axial center of the conductive member, and the first end surface. a disc-shaped first ceramic substrate having a second end surface extending from a second end of an outer peripheral surface toward the axis of the conducting member and a first through hole for inserting the conducting member; and a first cylindrical body formed by bonding two ceramic substrates from the outer peripheral side, wherein the outer peripheral surface includes a first metal layer starting from the second end, An end point of one metal layer is located between the first end and the second end.

In the airtight terminal of the present disclosure, the brazing material is less likely to leak into a narrow space such as an escape groove, so even if heating and cooling are repeated, the residual stress is less likely to increase, and the terminal can be used for a long period of time.

1 is a cross-sectional view showing an example of an airtight terminal of the present disclosure; FIG. 2 is an enlarged cross-sectional view of a joint portion of the second ceramic substrate of FIG. 1; FIG. (a) is an enlarged sectional view of a joint portion of a first ceramic substrate in FIG. 1, and (b) is an enlarged sectional view of a joint portion of another first ceramic substrate. (a) is a cross-sectional view enlarging a joint portion of the conducting member of FIG. 1, and (b) is a cross-sectional view enlarging a joint portion of another conducting member.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, in all the drawings of this specification, the same parts are denoted by the same reference numerals unless confusion occurs, and the description thereof will be omitted as appropriate.

FIG. 1 is a cross-sectional view showing an example of an airtight terminal of the present disclosure.

FIG. 2 is an enlarged cross-sectional view of a joint portion of the second ceramic substrate of FIG.

The airtight terminal 20 shown in FIG. A second ceramic having a cylindrical body 4, a second cylindrical body 5 axially connected to the first cylindrical body 4, and a second through hole 6 surrounding the first cylindrical body 4 in the thickness direction. It comprises a substrate 7 and a pipe 8 that joins the second ceramic substrate 7 on the side where the second cylindrical body 5 is located.

The first ceramic substrate 3 has a first annular portion 3b and a second annular portion 3c extending in the axial direction from both sides of each main surface of a base portion 3a located in the center. For example, the outer diameter of the first ceramic substrate 3 is 6 mm or more and 10 mm or less, and the distance between the annular end faces of the first annular portion 3b and the second annular portion 3c is 4 mm or more and 7 mm or less. A narrow space 16 is formed between the main surface of the base portion 3a located on the side of the second annular portion 3c and the opposing surface of the first cylindrical body 4 facing the main surface.

The outer diameter of the outermost periphery of the second ceramic substrate 7 is, for example, 15 mm or more and 18 mm or less, and the interval between the annular end faces is 5 mm or more and 9 mm or less.

Although the conductive member 1 shown in FIG. 1 has a columnar shape, it may have a tubular shape.

The second ceramic substrate 7 shown in FIG. 2 is joined to the pipe 8 by a brazing portion 11 via a second metal layer 13 provided on a step surface coaxial with the outer peripheral surface. The first cylindrical body 4 has a flange portion 4a that expands radially outward at a position opposite to the pipe 8, and the annular end face of the second ceramic substrate 7 positioned opposite to the pipe 8 is It is joined to the flange portion 4 a by the brazing portion 11 via the third metal layer 14 .

The second metal layer 13 and the third metal layer 14 are composed of metallized layers 13a and 14a positioned on the second ceramic substrate 7 side and coating layers 13b and 14b positioned on the metallized layers 13a and 14a, respectively. The metallized layers 13a and 14a are mainly composed of molybdenum and contain manganese. The coating layers 13b, 14b are mainly composed of nickel, copper or copper-nickel alloy, and may contain phosphorus or boron. The coating layers 13b and 14b are layers for preventing oxidation of the metallization layers 13a and 13b. For example, the thickness of the metallized layers 13a and 14a is 10 μm or more and 50 μm or less, and the thickness of the coating layers 13b and 14b is 2 μm or more and 4 μm or less. The brazing portion 11 is made of a brazing material containing silver as a main component, such as BAg-8, BAg-8A, or BAg-8B.

The brazing filler metal in the present disclosure is a brazing filler (hard brazing filler) with a melting point of 4550° C. or higher, which is used for brazing defined in JIS Z 3001-3: 2008 (ISO 857-2: 2005 (MOD)). , does not include solder (soft solder) with a melting point of less than 450° C., which is used for soldering as defined in the above standards.

3A is an enlarged cross-sectional view of a joint portion of the first ceramic substrate of FIG. 1, and FIG. 3B is an enlarged cross-sectional view of another first ceramic substrate joint portion.

The first ceramic substrate 3 shown in FIG. 3A is joined to the first cylindrical body 4 by a brazing portion 11 via a first metal layer 10 provided on a stepped surface 3y coaxial with the outer peripheral surface 3x. there is

The first ceramic substrate 3 shown in FIG. 3B is joined to the first cylindrical body 4 by a brazing portion 11 via a first metal layer 10 provided on a portion of the outer peripheral surface 3x.

3A and 3B, the first metal layer 10 consists of a metallized layer 10a positioned on the first ceramic substrate 3 side and a coating layer 10b positioned on the metallized layer 10a. The coating layer 10b is joined to the first cylindrical body 4 by a brazing portion 11 made of a brazing material containing silver as a main component, such as BAg-8, BAg-8A, BAg-8B.

3A and 3B, the first metal layer 10 consists of a metallized layer 10a positioned on the first ceramic substrate 3 side and a coating layer 10b positioned on the metallized layer 10a.

The metallized layer 10a is mainly composed of molybdenum and contains manganese. The coating layer 10b is mainly composed of nickel, copper, or a copper-nickel alloy, and may contain phosphorus or boron. The coating layer 10b is a layer for preventing oxidation of the metallized layer 10a.

For example, the thickness of the metallized layer 10a is 10 μm or more and 50 μm or less, and the thickness of the coating layer 10b is 2 μm or more and 4 μm or less. The coating layer 10b is joined to the first cylindrical body 4 by a brazing portion 11 made of a brazing material containing silver as a main component, such as BAg-8, BAg-8A, BAg-8B.

The first metal layer 10 may extend along the second end surface 3</b>E of the first ceramic substrate 3 .

With such a configuration, the reliability of bonding of the first ceramic substrate 3 to the first cylindrical body 4 is improved, so that the first ceramic substrate 3 can be easily removed from the first cylindrical body 4 even if heating and cooling are repeated. No peeling.

The main component in the coating layers 10b, 13b, and 14b in the present disclosure refers to a component of 88% by mass or more of the total 100% by mass of the components constituting the coating layers 10b, 13b, and 14b. It may contain phosphorus or the like. In the case of the coating layer 10b containing a copper-nickel alloy as the main component, the total content of copper and nickel is the content of the main component.

The content of elements in the coating layers 10b, 13b, and 14b may be determined using an X-ray fluorescence spectrometer (XRF) or an ICP emission spectrometer (ICP).

4(a) is an enlarged cross-sectional view of a joint portion of the conducting member in FIG. 1, and FIG. 4(b) is an enlarged cross-sectional view of a joint portion of another conducting member.

An annular body 12 is joined to the first ceramic substrate 3 with a brazing material in the middle of the conducting member 1 in the axial direction. The conducting member 1, the annular body 12, the first cylindrical body 4, the second cylindrical body 5 and the pipe 8 are made of Fernico system alloy, Fe--Ni alloy, Fe--Ni--Cr--Ti--Al alloy, Fe--Co--Cr alloy. or made of Fe--Cr--Al alloy. The first ceramic substrate 3 is made of ceramics containing aluminum oxide as a main component. The annular body 12 is connected to the annular surface of the first annular portion 3b and the inner circumference connected to the annular surface by a brazing portion 11 made of a silver-based brazing material such as BAg-8, BAg-8A, or BAg-8B. It is joined to a first ceramic substrate 3 having a fourth metal layer 15 on part of its surface. The fourth metal layer 15 is composed of a metallized layer 15a positioned on the first ceramic substrate 3 side and a coating layer 15b positioned on the metallized layer 15a. The first cylindrical body 4 and the second cylindrical body 5 are joined by a brazing material at the tip side of the inner peripheral surface of the first cylindrical body 4 and the tip side of the outer peripheral surface of the second cylindrical body 5 .

Here, the main component in the ceramics means a component of 85% by mass or more out of the total 100% by mass of the components constituting the ceramics, and the main component in the brazing material means the total 100% by mass of the components constituting the brazing material. %, 60% by mass or more.

Ceramics may contain at least one of silicon, calcium, and magnesium as an oxide, in addition to aluminum oxide, which is the main component.

After identifying the components that make up the ceramics using an X-ray diffractometer (XRD), the content of the elements is determined and identified using an X-ray fluorescence spectrometer (XRF) or an ICP emission spectrometer (ICP). It can be converted to the content of the selected component.

The element content of the components constituting the brazed portion 11 may be determined using an X-ray fluorescence spectrometer (XRF) or an ICP emission spectrometer (ICP).

The airtight terminal 20 has a third through hole 9a for inserting the pipe 8, and a fastening member (not shown) such as a bolt is inserted into the outer peripheral side of the third through hole 9a to form a vacuum container or a cryogenic liquid storage container (for example, a vacuum container or a cryogenic liquid storage container). not shown), the flange 9 encircling the pipe 8 on the side of the end face 8a. The flange 9 is made of a Fernico system alloy, Fe--Ni alloy, Fe--Ni--Cr--Ti--Al alloy, Fe--Co--Cr alloy, Fe--Cr--Al alloy, etc. For example, ICF34 fixed flange (TYPE: A ).

In FIG. 1, the space in the pipe 8 located on the left side of the first ceramic substrate 3 and the second ceramic substrate 7 is exposed to a vacuum or liquid nitrogen, and is exposed to the first ceramic substrate 3 and the second ceramic substrate 7. The spaces located on the right are each used in environments exposed to the atmosphere.

As shown in FIG. 3( a ), the airtight terminal 20 of the present disclosure includes a columnar or cylindrical conductive member 1 , a first ceramic substrate 3 , and a first cylindrical body that joins the first ceramic substrate 3 from the outer peripheral side. 4 and . The first ceramic substrate 3 extends toward the axis of the conductive member 1 from a first outer peripheral surface 3x, a stepped surface 3y coaxially positioned with the first outer peripheral surface 3x, and a first end portion 3d of the first outer peripheral surface 3x. It has a first end face 3D, a second end face 3E extending from a second end 3e of the stepped face 3y toward the axis of the conduction member 1, and a first through hole 2 for inserting the conduction member 1 in the thickness direction. . The stepped surface 3y includes a first metal layer 10 starting from the second end 3e, and an end point of the first metal layer 10 is located between the first end 3d and the second end e. be.

Alternatively, as shown in FIG. 3B, the airtight terminal 20 of the present disclosure includes at least the columnar or cylindrical conduction member 1, the first ceramic substrate 3, and the first ceramic substrate 3 joined from the outer peripheral side. and a first cylindrical body 4. The first ceramic substrate 3 includes a first outer peripheral surface 3x, a first end surface 3D extending from a first end portion 3d of the first outer peripheral surface 3x toward the axial center of the conductive member 1, and a second end portion of the first outer peripheral surface 3x. It has a second end surface 3E extending from 3e toward the axis of the conducting member 1, and a first through hole 2 for inserting the conducting member 1 in the thickness direction. The outer peripheral surface 3x includes a first metal layer 10 starting from the second end 3e, and an end point of the first metal layer 10 is located between the first end and the second end.

With this configuration, the first ceramic substrate 3 can be firmly joined to the first cylindrical body 4 by the brazing material, and the brazing material is less likely to leak into the narrow space 16, thereby preventing the first cylindrical body 4 from leaking. Since unnecessary joining with the first ceramic substrate 3 is suppressed at this portion, cracks are less likely to occur in the second ceramic substrate 7 .

3(a) and 3(b), the end point of the first metal layer 10 extends from the second end 3e to the distance A between the first end 3d and the second end 3e. may be located at a distance of 40% or more and 80% or less of . By adopting such a configuration, it is possible to further reduce leakage of the brazing material while maintaining high bonding strength between the first ceramic substrate 3 and the first cylindrical body 4 .

Further, the conducting member 1 may have a diameter-reduced portion 1 a at a position facing the first ceramic substrate 3 . With such a configuration, even if the brazing material for joining the conductive member 1 and the first ceramic substrate 3 flows excessively from the annular body 12 side, it can be received in the space on the outer peripheral side of the reduced diameter portion 1a. , the coaxiality of the conducting member 1 with respect to the first through hole 2 is less likely to be impaired.

Furthermore, since the outer diameter of the conductive member 1 positioned radially above the base portion 3a is smaller than the outer diameter of the conductive member 1 positioned radially above the first annular portion 3b and the second annular portion 3c, the first The characteristic impedances of the base portion 3a of the ceramic substrate 3 having a large outer diameter and the conducting member 1 can be equalized, and the characteristic impedances can be matched as a whole.

A second cylindrical body 5 axially connected to the first cylindrical body 4, a second ceramic substrate 7 having a second through hole 6 for surrounding the first cylindrical body 4 in the thickness direction, and a second cylinder It comprises a pipe 8 joined to a part of the outer peripheral surface of the second ceramic substrate 7 on the side where the body 5 is located, and a flange 9 located on the outer peripheral side of the pipe 8, the flange 9 being the second ceramic substrate 7. It may surround the side of the end surface 8a located on the opposite side.

With such a configuration, the distance from the end face 8a to the second ceramic substrate 7 becomes large, so even if the flange 9 is welded and fixed around the end face 8a by a TIG (Tungsten Inert Gas) welding method, welding is possible. Since the generated heat is less likely to be transmitted to the second ceramic substrate 7, the second ceramic substrate 7 is less likely to crack.

The joint portion between the first ceramic substrate 3 and the conducting member 1 is preferably located away from the main surface 9c of the flange 9 on the first cylindrical body 4 side toward the first cylindrical body. (That is, in FIG. 1, the joint between the first ceramic substrate 3 and the conducting member 1 is located on the right side of the imaginary plane in which the main surface 9c of the flange 9 on the side of the first cylindrical body 4 is located. 9 should be located to the left of the imaginary plane).

When the joint between the first ceramic substrate 3 and the conductive member 1 is at this position, the heat generated by welding is less likely to be transmitted to this joint. 1 Ceramic substrate 3 becomes difficult to generate.

Also, the joint portion between the second ceramic substrate 7 and the pipe 8 is preferably located away from the main surface 9c of the flange 9 on the first cylindrical body 4 side toward the first cylindrical body 4 side. (That is, in FIG. 1, the joint portion between the second ceramic substrate 7 and the pipe 8 is located on the right side of the imaginary plane where the main surface 9c of the flange 9 on the side of the first cylindrical body 4 is located, and the flange 9 should be located to the left of the above imaginary plane).

When the joint between the second ceramic substrate 7 and the pipe 8 is at this position, the heat generated by welding is less likely to be transmitted to this joint, so the stress remaining in the second ceramic substrate 7 is suppressed, and cracks are prevented from occurring. It is even less likely to occur inside the ceramic substrate 7 .

Next, an example of the method for manufacturing the airtight terminal of the present disclosure will be described.

The first ceramic substrate and the second ceramic substrate can be obtained by the following manufacturing method.

First, aluminum oxide powder, which is the main component, powders of magnesium hydroxide, silicon oxide, calcium carbonate and zirconium oxide, a dispersant for dispersing the aluminum oxide powder if necessary, and an organic binder are mixed in a ball mill. Wet mix with a bead mill or vibrating mill to form a slurry.

Here, the average particle size (D ₅₀ ) of the aluminum oxide powder is 3 μm or less, preferably 1 μm or less, and the content of the magnesium hydroxide powder in the total 100% by mass of the powder is 0.87% to 1.07% by mass. % by mass, the content of silicon oxide powder is 6.1% by mass to 7.5% by mass, the content of calcium carbonate powder is 2.5% by mass to 3.1% by mass, and the content of zirconium oxide is 1.0% by mass. It is 0% by mass to 1.3% by mass.

The wet-mixing time is, for example, 40 to 50 hours. Examples of organic binders include paraffin wax, wax emulsion (wax + emulsifier), PVA (polyvinyl alcohol), PEG (polyethylene glycol), PEO (polyethylene oxide), and the like.

Next, the slurry obtained by the above method is spray granulated to obtain granules, and the granules are molded by powder press molding or cold isostatic molding to obtain a disk-shaped compact. .

Then, the first ceramic substrate and the second ceramic substrate can be obtained by forming through-holes, stepped surfaces, etc. by cutting, and firing the annular molded body at a temperature of 1550° C. or more and 1750° C. or less.

In order to obtain joints between the second ceramic substrate and the pipe and the first cylinder, joints between the first ceramic substrate and the conducting member, and joints between the first ceramic substrate and the first cylinder, the second ceramic substrate After forming a metallized layer by the Mo—Mn method or the like on the target surface of each joint of the first ceramic substrate and the first ceramic substrate, a coating layer containing nickel, copper, or a copper-nickel alloy as a main component is formed by a plating method. .

Then, each joint is formed by applying a silver-based brazing material such as BAg-8, BAg-8A, or BAg-8B to the target surface of each joint and heat-treating it at an appropriate temperature. can obtain the airtight terminal of the present disclosure.

Here, the appropriate temperature is the brazing temperature described in JIS Z 3281:1998. To obtain an airtight terminal with a flange, the flange is attached to the outer peripheral side of the end face of the pipe located on the opposite side of the second ceramic substrate, and is welded and fixed by TIG (Tungsten Inert Gas) welding. , the hermetic terminal of the present disclosure can be obtained.

The airtight terminal of the present disclosure obtained by the above-described manufacturing method can be used for a long period of time because cracks are less likely to occur even when the second ceramic substrate is subjected to high heat.

The present invention is not limited to the embodiments described above, and various modifications and improvements are possible in accordance with the technical idea of the present invention.

1 conducting member 1a reduced diameter portion 2 first through hole 3 first ceramic substrate 3a base portion 3b first annular portion 3c second annular portion 4 first cylindrical body 5 second cylindrical body 6 second through hole 7 second ceramic substrate 8 Pipe 9 Flange 9a Third through-hole 9b Fourth through-hole 10 First metal layer 10a Metallized layer 10b Coating layer 11 Brazed part 12 Annular body 13 Second metal layer 13a Metallized layer 13b Coating layer 14 Third metal layer 14a Metallized layer 14b coating layer 15 fourth metal layer 15a metallized layer 15b coating layer 16 narrow space 20 hermetic terminal

Claims (7)

a columnar or cylindrical conducting member;
a first outer peripheral surface, a stepped surface coaxially positioned with the first outer peripheral surface, a first end surface extending from a first end of the first outer peripheral surface toward an axial center of the conducting member, and a second stepped surface of the stepped surface a disk-shaped first ceramic substrate having a second end surface extending from an end toward the axis of the conducting member and a first through hole for inserting the conducting member;
an airtight terminal comprising a first cylindrical body that joins the first ceramic substrate from the outer peripheral side,
The stepped surface includes a first metal layer starting from the second end, and an end point of the first metal layer is located between the first end and the second end. terminal. a columnar or cylindrical conducting member;
a first outer peripheral surface, a first end face extending from a first end of the first outer peripheral surface toward the axis of the conducting member, and a second end of the first outer peripheral surface toward the axial center of the conducting member a disc-shaped first ceramic substrate having a second end surface extending and a first through hole for inserting the conducting member;
an airtight terminal comprising a first cylindrical body formed by bonding the first ceramic substrate from the outer peripheral side,
wherein the outer peripheral surface comprises a first metal layer starting at the second end and terminating at a location between the first end and the second end; terminal. 3. The airtight terminal according to claim 1, wherein said end point is located at a distance of 40% or more and 80% or less of the distance between said first end and said second end from said second end. 4. The airtight terminal according to any one of claims 1 to 3, wherein said conduction member has a diameter-reduced portion at a position facing said first ceramic substrate. a second cylindrical body axially connected to the first cylindrical body;
A second ceramic substrate having a second through hole in the thickness direction for surrounding the first cylindrical body, and a pipe joined to a part of the outer peripheral surface of the second ceramic substrate on the side where the second cylindrical body is located. and,
5. The airtight terminal according to any one of claims 1 to 4, further comprising a flange located on the outer peripheral side of said pipe, said flange surrounding an end face located on the opposite side of said second ceramic substrate. . The first ceramic substrate and the conducting member are joined together, and the joining portion between the first ceramic substrate and the conducting member comprises:
6. The airtight terminal according to claim 5, wherein the flange is located away from the main surface of the flange on the side of the first cylindrical body toward the first cylindrical body. The second ceramic substrate and the pipe are joined together, and the junction between the second ceramic substrate and the pipe comprises:
7. The airtight terminal according to claim 5, wherein the flange is located away from the main surface of the flange on the side of the first cylindrical body toward the first cylindrical body.

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