WO2020054703A1

WO2020054703A1 - Hermetic terminal

Info

Publication number: WO2020054703A1
Application number: PCT/JP2019/035503
Authority: WO
Inventors: 遥大村; 晃一岩本
Original assignee: 京セラ株式会社
Priority date: 2018-09-11
Filing date: 2019-09-10
Publication date: 2020-03-19
Also published as: EP3852199A1; EP3852199A4; JP7037662B2; EP3852199B1; JPWO2020054703A1

Abstract

This hermetic terminal includes a plate-like ceramic substrate that has, in the thickness direction, a through hole for inserting a columnar conducting member, a first tube body that encloses the ceramic substrate, and a second tube body that is coupled coaxially to the first tube body. The first tube body comprises a fernico alloy, an Fe-Ni alloy, an Fe-Ni-Cr-Ti-Al alloy, an Fe-Cr-Al alloy, or an Fe-Co-Cr alloy. The second tube body comprises austenitic stainless steel which has a nickel content of 10.4 mass% or more.

Description

Airtight terminal

The present disclosure relates to a hermetic terminal.

Conventionally, a hermetic terminal used in vacuum equipment, nuclear power equipment, etc. has a contact pin 21, a heat-resistant insulator 22, and a pipe flange (cylinder) like an hermetic terminal 30 shown in FIG. 5 in order to obtain high leakage resistance. 23 are required to be air-tightly joined to each other, and this joining is performed by brazing or the like, has a required mechanical strength, and is required to be sufficiently resistant to impact and high temperature. For this reason, alumina is used as the heat-resistant insulator 22, the surface is metallized, and the contact pin 21 and the pipe flange 23 are air-tightly joined thereto by brazing, and the contact pin 21 and the pipe flange 23 have a coefficient of thermal expansion with respect to alumina. In order to reduce the difference between the two, it is usually formed of an iron-nickel alloy or an iron-nickel-cobalt alloy.

In recent years, as shown in Non-Patent Document 1, multi-pole terminals have been used as hermetic terminals for extracting signals from a liquid hydrogen tank of a rocket.

Japanese Patent No. 2519642

The hermetic terminal according to the present disclosure includes a plate-shaped ceramic substrate provided with a through hole for inserting a columnar conductive member in a thickness direction, a first cylindrical body surrounding the ceramic substrate, and a coaxial with the first cylindrical body. A second cylinder connected to the first cylinder, wherein the first cylinder is a fernico-based alloy, an Fe-Ni alloy, an Fe-Ni-Cr-Ti-Al alloy, an Fe-Cr-Al alloy, or an Fe-Co alloy. The second cylindrical body is made of an austenitic stainless steel having a nickel content of 10.4% by mass or more.

1A is a perspective view of a first cylindrical body side, and FIG. 2B is a perspective view of a second cylindrical body side, illustrating an example of an airtight terminal of the present disclosure. FIG. 1A is a view showing an example of a cross section of an airtight terminal of FIG. 1 along an axial direction of a first cylindrical body and a second cylindrical body, and FIG. 1B is a side view of FIG. (c) is a cross-sectional view showing an example in which the portion A shown in (a) is enlarged, (d) is a cross-sectional view showing another example in which the A portion shown in (a) is enlarged, and (e) is a sectional view. It is sectional drawing which shows an example which expanded the B section shown to a). It is sectional drawing which shows the other example which expanded the A section of the airtight terminal shown in FIG. FIG. 1A is a view showing another example of a cross section along the axial direction of a first cylindrical body and a second cylindrical body, and FIG. 1B is a side view of FIG. (C) is a cross-sectional view showing an example in which the portion A shown in (a) is enlarged, (d) is a cross-sectional view showing another example in which the portion A shown in (a) is enlarged, and (e). FIG. 2 is a cross-sectional view showing an example in which a portion B shown in FIG. It is a perspective view showing an example of the conventional airtight terminal.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, in all the drawings of the present specification, the same parts are denoted by the same reference numerals and the description thereof will be appropriately omitted unless confusion occurs.

1 shows an example of the hermetic terminal of the present disclosure, wherein (a) is a perspective view of the first cylindrical body, and (b) is a perspective view of the second cylindrical body.

2A and 2B are views showing an example of a cross section along the axial direction of a first cylindrical body and a second cylindrical body, and FIG. 2B is a side view of FIG. (C) is a cross-sectional view showing an example in which the portion A shown in (a) is enlarged. (D) is a cross-sectional view showing another example in which the portion A shown in (a) is enlarged. (e) is a cross-sectional view showing an example in which a portion B shown in (a) is enlarged.

The hermetic terminal 20 shown in FIGS. 1 and 2 includes a plate-shaped ceramic substrate 3 provided with a through hole 2 for inserting the columnar conductive member 1 in a thickness direction, and a first cylindrical body 4 surrounding the ceramic substrate 3. , A second cylinder 5 coaxially connected to the first cylinder 4.

The conductive member 1 includes a columnar base 1a inserted into the through-hole 2, and a flange 1b facing the ceramic substrate 3 in the axial direction of the columnar base 1a. The conductive member 1 is made of a fernico-based alloy, an Fe-Ni alloy, an Fe-Ni-Cr-Ti-Al alloy, an Fe-Co-Cr alloy or an Fe-Cr-Al alloy, and the ceramic substrate 3 is made of aluminum oxide. The conductive member 1 is supported on a ceramic substrate 3 having a metallized layer 10 formed on the surface thereof by a brazing material mainly composed of silver, such as BAg-8, BAg-8A, and BAg-8B. Have been.

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

The ceramics may contain, as an oxide, at least one of silicon, calcium, and magnesium other than the main component, aluminum oxide.

The components constituting the ceramics are identified using an X-ray diffractometer (XRD), and then the content of elements is determined using an X-ray fluorescence analyzer (XRF) or an ICP emission spectrometer (ICP) to identify the components. What is necessary is just to convert into the content of the done component.

For the components constituting the brazing material, the content of the elements constituting the joining layer made of the brazing material may be determined using an X-ray fluorescence analyzer (XRF) or an ICP emission spectrometer (ICP).

The first cylindrical body 4 includes a shaft 4a and a head 4b having an outer diameter larger than the outer diameter of the shaft 4a. Similarly, the second cylindrical body 5 includes a shaft portion 5a and a head portion 5b having an outer diameter larger than the outer diameter of the shaft portion 5a.

The hermetic terminal 20 is fixed to a low-temperature liquid storage container or the like (not shown) by inserting a plurality of through holes 6a for inserting the second cylindrical body 5 and fastening members such as bolts on the outer peripheral side thereof. And a plurality of through holes 6b. The flange 6 is made of, for example, austenitic stainless steel.

As shown in FIG. 2A, the flange 6 surrounds the shaft 4a of the first cylinder 4 and the shaft 5a of the second cylinder 5, and separates the left and right environments with the flange 6 as a boundary. are doing.

In FIG. 2A, the head 4b of the first cylinder 4 and the head 4b of the shaft 4a located on the left side of the ceramic substrate 3 are located on the right side of the ceramic substrate 3 in an environment exposed to the atmosphere. The second cylinders 5 are used in an environment exposed to liquid hydrogen. The shaft portion 4a of the first cylinder 4 located on the right side of the ceramic substrate 3 is configured by the second cylinder 5 so as not to be directly exposed to liquid hydrogen.

The first cylinder 4 is made of a fernico-based alloy, an Fe-Ni alloy, an Fe-Ni-Cr-Ti-Al alloy, an Fe-Cr-Al alloy, or an Fe-Co-Cr alloy. The austenitic stainless steel has a nickel content of 10.4% by mass or more.

When the first cylinder 4 is made of the above-mentioned alloy, the residual stress hardly accumulates on the ceramic substrate 3 even when heating and cooling are repeated, since the linear expansion coefficient of these alloys is small compared to the linear expansion coefficient of aluminum oxide. Therefore, cracks hardly occur in the ceramic substrate 3. Further, when the second cylindrical body 5 is made of austenitic stainless steel having a nickel content of 10.4% by mass or more, embrittlement due to hydrogen hardly occurs, and thus the second cylindrical body 5 can be used for a long period of time.

The second cylinder 5 is made of, for example, SUS310S, SUS316L, SUS316LN, SUS316J1L, or SUS317L.

Note that the first cylinder 4 and the second cylinder 5 shown in FIGS. 1 and 2 are both cylinders and the ceramic substrate 3 is a disk, but both the first cylinder 4 and the second cylinder 5 are square. The cylindrical body and the ceramic substrate 3 may be square plates.

端 As shown in FIG. 2C, the end of the second cylinder 5 on the first cylinder 4 side is provided with a step surface 5c.

As shown in FIG. 2D, the end of the first cylinder 4 on the second cylinder 5 side has a step surface 4c.

As shown in FIGS. 2C and 2D, a step is formed on at least one of the end of the second cylinder 5 on the first cylinder 4 side and the end of the first cylinder 4 on the second cylinder 5 side. It may have

surfaces

4c and 5c. In FIG. 2C, the outer peripheral surface of the second cylindrical body 5 has the step surface 5c, but the inner peripheral surface of the second cylindrical body 5 may have the step surface. In FIG. 2D, the outer peripheral surface of the first cylindrical body 4 has a step surface 4c, but the inner peripheral surface of the first cylindrical body 4 may have a step surface.

With such a configuration, it is difficult for hydrogen volatilized by applying a high pressure to pass through the gap between the first cylindrical body 4 and the second cylindrical body 5, so that the hydrogen is discharged to the outside via the internal space of the first cylindrical body 4. It is less likely to leak.

FIG. 3 is a cross-sectional view showing another example in which the portion A of the hermetic terminal shown in FIG. 2 is enlarged.

As shown in FIG. 3, the second cylindrical body 5 may include a coating layer 5 d containing nickel, copper, or a copper-nickel alloy as a main component at least on a joint with the first cylindrical body 4.

With such a configuration, the first cylinder 4 and the second cylinder 5 can be firmly joined to each other by the joining layer 7 made of a brazing material, so that the reliability is improved.

In addition, the second cylindrical body 5 has not only a joint portion but also a surface exposed to liquid hydrogen, for example, nickel, copper, or a copper-nickel alloy as a main component on at least one of an inner peripheral surface, an outer peripheral surface, and an end surface. A coating layer 5d may be provided.

構成 With such a configuration, the embrittlement of the austenitic stainless steel constituting the second cylindrical body 5 due to hydrogen can be delayed, so that it can be used for a longer period of time.

２The second cylindrical body 5 shown in FIG. 3 has a coating layer 5d on the inner peripheral surface, the outer peripheral surface, and the end surface.

The first cylindrical body 4 may include a coating layer 4d containing nickel, copper, or a copper-nickel alloy as a main component at least on a joint with the second cylindrical body 5.

With such a configuration, the first cylindrical body 4 and the second cylindrical body 5 can be firmly joined by the brazing material, so that the reliability is improved.

As shown in FIG. 3, the inner peripheral surface of the first cylindrical body 4 may be located outside the outer peripheral surface of the second cylindrical body 5.

With such a configuration, the first cylinder 4 has a smaller linear expansion coefficient than the second cylinder 5, so that it is difficult for the gap to expand even if heating and cooling are repeated. Leakage to the outside via the internal space of the body 4 is reduced.

As shown in FIG. 3A, when the second cylinder 5 has a step surface 5c at the end on the first cylinder 4 side, the outer peripheral surface corresponds to the step surface 5c.

Furthermore, as shown in FIGS. 1 and 2, a flange 6 that surrounds the second cylinder 5 and that is joined to the outer peripheral surface of the second cylinder 5 may be further provided.

With such a configuration, different environments can be separated on the outer peripheral side of the second cylindrical body 5 with the flange 6 as a boundary.

As shown in FIG. 2, the flange 6 includes a second concave portion 6 d on the side of the second cylindrical body 5, and has a U-shaped flange 8 having a cross section along the axial direction of the second cylindrical body 5. Is mounted in the second recess 6 d, and the second cylindrical body 5 and the flange 6 are joined via the flange 8.

The flange 8 may include a coating layer (not shown) containing nickel, copper, or a copper-nickel alloy as a main component at least on a joint with the second cylindrical body 5. A coating layer (not shown) may be provided.

主成分 In addition, the main component in the coating layer in the present disclosure refers to a component of 88% by mass or more of a total of 100% by mass of the components constituting the coating layer, and may include phosphorus and the like other than the main component. In the case of a coating layer containing a copper-nickel alloy as a main component, the total of the respective contents of copper and nickel is the content of the main component.

成分 The components in the coating layer may be determined by X-ray fluorescence spectroscopy (XRF) or ICP emission spectroscopy (ICP) to determine the content of the elements.

The flange 8 and the second cylindrical body 5 are joined by a brazing material containing silver as a main component such as BAg-8, BAg-8A, and BAg-8B, and the flange 6 and the flange 8 are formed by TIG (Tungsten Inert Gas). The members are welded by a welding method, and the welding is performed after the joining of the members with the brazing material is completed.

The flange 6 is provided with a first concave portion 6c on the first cylindrical member 4 side, and a joint between the ceramic substrate 3 and the first cylindrical member 4 is closer to the second cylindrical member 5 than the bottom surface 6c1 of the first concave portion 6c. 2A, the joint between the ceramic substrate 3 and the first cylindrical body 4 is located on the left side of the virtual plane where the bottom surface 6c1 of the first recess 6c is located. , The second cylindrical body 5 is preferably located on the right side of the drawing with respect to the virtual plane).

If the joint between the ceramic substrate 3 and the first cylindrical body 4 is at this position, the heat generated by welding is less likely to be transmitted to the ceramic substrate 3, so that residual stress is less likely to be generated in the ceramic substrate 3, so that cracks are formed in the ceramic substrate 3. It hardly occurs in the substrate 3.

Here, the first concave portion 6c is a counterbore for facilitating the mounting of the first cylindrical body 4.

鍔 Flange 8 may be austenitic stainless steel having a nickel content of 10.4% by mass or more. When the flange portion 8 has such a configuration, embrittlement due to hydrogen is unlikely to occur, so that the flange portion 8 can be used for a long time.

The flange 8 is made of, for example, SUS310S, SUS316L, SUS316LN, SUS316J1L or SUS317L.

The content of nickel in the second cylinder 5 and the flange 8 may be measured using an inductively coupled plasma (ICP) emission spectrometer or a fluorescent X-ray analyzer (XRF).

4A and 4B show the hermetic terminal of FIG. 1, wherein FIG. 4A is a diagram showing another example of a cross section along the axial direction of the first cylinder and the second cylinder, and FIG. It is a side view, (c) is sectional drawing which shows an example which expanded A part shown to (a), and (d) is sectional drawing which shows another example which expanded A part shown to (a). And (e) is a cross-sectional view showing an example in which the portion B shown in (a) is enlarged.

As shown in FIG. 4, a plurality of conductive members 1 are individually inserted into a plurality of through holes 2, and a ceramic substrate 3 is provided around the through hole 2 with a step recessed from at least one of

main surfaces

3 b and 3 c. A portion 9 (9a, 9b) may be provided.

With such a configuration, the creepage distance between the columnar bases 1a of the adjacent conductive members 1 is increased, so that the generation of the creeping discharge between the columnar bases 1a can be suppressed.

The ceramic substrate 3 includes a stepped portion 9 which is recessed from both the

main surfaces

3b and 3c around the through hole 2, and one of the stepped portions 9a further includes a metallized layer 10 on the stepped surface. The step 9a on the side provided with the layer 10 may be deeper than the step 9b on the side not provided with the metallized layer 10. Here, the metallized layer 10 is for fixing the conductive member 1 to the ceramic substrate 3 by brazing, and has a thickness of, for example, 5 μm or more and 55 μm or less.

If the step 9a on the side provided with the metallized layer 10 is deeper than the step 9b on the side not provided with the metallized layer 10, the creepage distance between the columnar bases 1a of the adjacent conductive members 1 can be increased. Even if the metallized layer 10 is made thicker, the occurrence of creeping discharge between the conductive members 1 can be suppressed. Here, the depth of the step portion 9a is a distance from the main surface to the step surface, and does not include the thickness of the metallized layer 10.

(4) The depth of the step portion 9 a on the side provided with the metallized layer 10 may be 45% or less of the thickness of the ceramic substrate 3. When the depth of the step portion 9a is within this range, the mechanical strength of the ceramic substrate 3 around the through hole 2 can be secured. Here, the thickness of the ceramic substrate 3 is the distance between the two

main surfaces

3b and 3c of the ceramic substrate 3.

As shown in FIG. 2, a plurality of conductive members 1 are individually inserted into a plurality of through holes 2, and a ceramic substrate 3 is provided around at least one main surface (see FIG. In the example shown in (1), a ridge 3a extending from the main surface 3c) may be provided. With such a configuration, the metallized layer 10 facing the conductive member 1 can be lengthened, so that the reliability of joining the conductive member 1 to the ceramic substrate 3 can be increased.

Further, the ceramic substrate 3 has a plurality of open pores on the stepped surface provided with the metallized layer 10 or the tip end face of the convex portion 3a, and the value obtained by subtracting the average value of the circle equivalent diameter of the open pores from the distance between the centers of gravity of the open pores is It may be 20 μm or more and 50 μm or less.

If the value obtained by subtracting the average value of the equivalent circle diameter of the open pores from the distance between the centers of gravity of the open pores is 20 μm or more, the open pores become difficult to communicate with each other even in an environment where heating and cooling are repeated. In addition, the mechanical strength can be maintained, and the metallized layer 10 is less likely to crack. Further, if the value obtained by subtracting the average value of the circle-equivalent diameter of the open pores from the distance between the centers of gravity of the open pores is 50 μm or less, the density of the open pores increases, so the anchoring effect of the metallized layer 10 on the ceramic substrate 3. And the adhesion strength of the metallized layer 10 increases.

When the value obtained by subtracting the average value of the equivalent circle diameter of the open pores from the distance between the centers of gravity of the open pores is 20 μm or more and 50 μm or less, the mechanical strength of the ceramic substrate 3 is maintained, the cracks in the metallized layer 10 are suppressed, and the metallized layer 10 is suppressed. Can be improved in adhesion strength.

When obtaining the distance between the centers of gravity of the open pores, the step surface of the ceramic substrate 3 or the tip end surface of the protruding ridge portion 3a is polished with diamond abrasive to have a mirror surface. Here, the arithmetic average roughness Ra of the mirror surface is set to 0.2 μm or less using a measuring method based on JIS B 0601: 2013. A portion where the size and distribution of the open pores are averagely observed is selected from the mirror surface, and the magnification is set to 200 times using an optical microscope to measure a range having an area of, for example, 1.5 × 10 ⁵ μm ^2. Area.

With this measurement area as a measurement target, a method called a distance between centers of gravity method of image analysis software “A image kun (Ver2.52)” (registered trademark, manufactured by Asahi Kasei Engineering Corporation, hereinafter referred to as image analysis software) is applied. Thus, the distance between the centers of gravity of the adjacent open pores can be obtained. The distance between the centers of gravity of the open pores in the present disclosure is a linear distance connecting the centers of gravity of the open pores.

測定 For measuring the circle-equivalent diameter of the open pores, a method called particle analysis of image analysis software is applied to the above measurement area.

In addition, as the setting conditions of the distance between centers of gravity method and the particle analysis, for example, the brightness is dark, the binarization method is manual, the small figure removal area is 1 μm ² , and the noise removal filter is provided. The threshold may be set so that the appearing marker matches the shape of the open pore. The threshold value is, for example, 155.

Next, an example of a method for manufacturing a hermetic terminal according to the present disclosure will be described.

。Preparing the first cylinder, the second cylinder, and the ceramic substrate having the conductive member inserted into the through hole.

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

First, an aluminum oxide powder as a main component, magnesium hydroxide, silicon oxide, calcium carbonate and zirconium oxide powder, a dispersant for dispersing the aluminum oxide powder as needed, and an organic binder, a ball mill, A slurry is obtained by wet mixing with a bead mill or a vibration mill.

Here, the average particle diameter (D ₅₀ ) of the aluminum oxide powder is 3 μm or less, preferably 1 μm or less, and the content of magnesium hydroxide powder in the total 100% by mass of the powder is 0.87% to 1.07%. % 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.% by mass. 0 mass% to 1.3 mass%.

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

Next, after the slurry obtained by the above-described method is spray-granulated to obtain granules, the granules are formed by a powder press molding method or a cold isostatic pressing method to obtain a disk-shaped molded body. . {Circle around (2)} Then, a through-hole and a step or a ridge are formed by cutting, and the formed body having the through-hole or the like is fired at a temperature of 1550 ° C. or more and 1750 ° C. or less to obtain a ceramic substrate.

Here, a plurality of open pores are provided on the tip surface of the stepped surface or the ridge portion provided with the metallized layer, and a value obtained by subtracting the average value of the circle equivalent diameter of the open pores from the distance between the centers of gravity of the open pores is not less than 20 μm and not more than 50 μm. In order to obtain a certain ceramic substrate, a compact may be produced using a cold isostatic pressing method at a molding pressure of 98 MPa to 147 MPa, and fired at a temperature of 1580 ° C. to 1750 ° C.

A junction between the conductive member and the ceramic substrate, a junction between the first cylinder and the second cylinder, a junction between the first cylinder and the ceramic substrate, a junction between the second cylinder and the first cylinder, and A coating layer containing nickel, copper, or a copper-nickel alloy as a main component may be previously formed on at least one of the joints of the ceramic substrate with the first cylinder by a plating method.

被覆 The above-described coating layer may be formed on the entire surface of the conductive member, the first cylindrical body, and the second cylindrical body.

When at least one of the end of the second cylinder on the first cylinder side and the end of the first cylinder on the second cylinder side, the coating layer may be formed on the step surface. .

In addition, at least one of the joint portion of the ceramic substrate with the conductive member and the joint portion of the ceramic substrate with the first cylindrical body is formed by forming a metallized layer in advance by a Mo—Mn method, and then plating nickel or copper by a plating method. Alternatively, a coating layer mainly containing a copper-nickel alloy may be formed.

被覆 The coating layer may be formed on the entire outer peripheral surface of the ceramic substrate.

Then, a brazing material containing silver as a main component such as BAg-8, BAg-8A, or BAg-8B is applied to each of the opposing joints, and heat treatment is performed at an appropriate temperature. The disclosed hermetic terminal can be obtained.

適正 Here, the appropriate temperature is a brazing temperature described in JIS Z 3281: 1998.

In order to obtain an airtight terminal provided with a flange, a first cylindrical body, a ceramic substrate in which a conductive member is inserted into a through hole, and a second cylindrical body in which a flange is mounted are prepared.

Then, after joining the opposed joints with the brazing material, a flange is attached to the outer peripheral side of the flange, and is welded and fixed by a TIG (Tungsten Inert Gas) welding method to obtain an airtight terminal of the present disclosure. be able to.

気 The hermetic terminal of the present disclosure obtained by the above-described manufacturing method has high brittleness to hydrogen and can be used for a long time.

The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made based on the technical idea of the present invention.

For example, in the above-described embodiment, an example in which the second cylindrical body 5 is joined to the flange 6 via the flange 8 has been described, but the second cylindrical body 5 may be directly joined to the flange 6. . Further, in the above-described embodiment, an example is shown in which the flange 8 has a U-shaped cross section. However, the flange 8 may have another shape such as an L-shaped cross section. When the flange portion 8 has a U-shape or an L-shape, the bent portion may be curved. Further, in the above-described embodiment, the example in which the flange portion 8 is joined to the second concave portion 6d of the flange 6 has been described. However, the flange 6 does not have the second concave portion 6d, and the inner peripheral surface of the flange 6 or the second concave portion 6d. The flange 8 may be joined to the main surface on the side of the two cylinders 5.

REFERENCE SIGNS LIST 1 conductive member 2 through hole 3 ceramic substrate 3 a

convex ridge

3 b, 3 c main surface 4 first cylinder 5 second cylinder 6 flange 7 bonding layer 8 flange 9 step 10 metallization layer 20 airtight terminal

Claims

A plate-shaped ceramic substrate provided with a through hole for inserting a columnar conductive member in a thickness direction, a first cylindrical body surrounding the ceramic substrate, and a first cylindrical body coaxially connected to the first cylindrical body. A first cylindrical body made of a fernico-based alloy, an Fe—Ni alloy, an Fe—Ni—Cr—Ti—Al alloy, an Fe—Cr—Al alloy, or an Fe—Co—Cr alloy; The hermetic terminal, wherein the second cylinder is made of austenitic stainless steel having a nickel content of 10.4% by mass or more.
The airtight terminal according to claim 1, wherein at least one of an end of the second cylindrical body on the first cylindrical body side and an end of the first cylindrical body on the second cylindrical body side has a step surface.
The hermetic terminal according to claim 1, wherein the second cylindrical body includes a coating layer containing nickel, copper, or a copper-nickel alloy as a main component, at least on a joint with the first cylindrical body.
The airtight terminal according to any one of claims 1 to 3, wherein an inner peripheral surface of the first cylindrical body is located outside an outer peripheral surface of the second cylindrical body.
The hermetic terminal according to any one of claims 1 to 4, further comprising a flange that is joined to an outer peripheral surface of the second cylindrical body and surrounds the second cylindrical body.
The flange is provided with a second concave portion on the side of the second cylindrical body, and a flange portion having a U-shaped cross section along the axial direction of the second cylindrical body is attached to the second concave portion. The cylinder and the flange are joined via the flange, and the flange includes a first concave portion on the first cylinder side, and a joint between the ceramic substrate and the first cylinder is provided. The hermetic terminal according to claim 5, wherein the terminal is further away from the second cylindrical body than the bottom surface of the first recess.
The hermetic terminal according to claim 6, wherein the collar portion is an austenitic stainless steel having a nickel content of 10.4% by mass or more.
The plurality of conductive members are individually inserted into the plurality of through holes, and the ceramic substrate includes a stepped portion that is recessed from at least one of the main surfaces around the through hole. An airtight terminal according to claim 7.
The ceramic substrate, around the through hole, includes a stepped portion that is respectively depressed from both main surfaces, and one of the stepped portions further includes a metallized layer on the stepped surface, and includes the metallized layer. The hermetic terminal according to claim 8, wherein the step portion on the side where the metallized layer is provided is deeper than the step portion on the side not provided with the metallized layer.
The hermetic terminal according to claim 9, wherein a depth of the step portion on a side provided with the metallized layer is 45% or less of a thickness of the ceramic substrate.
The plurality of conductive members are individually inserted into the plurality of through-holes, and the ceramic substrate is provided with a ridge extending from at least one of the main surfaces around the through-hole. An airtight terminal according to any one of claims 1 to 7.
The ceramic substrate is provided with a plurality of open pores on a step surface or a tip end surface of the convex portion provided with the metallized layer, and a value obtained by subtracting an average value of a circle equivalent diameter of the open pores from a distance between centers of gravity of the open pores is 20 μm. The hermetic terminal according to any one of claims 9 to 11, which is not less than 50 µm.