Compression-sealed glass hermetic seal lead pin and manufacturing method thereof, as well as airtight terminal and electric compressor

Abstract

To provide a lead pin for a compression-sealed glass hermetic seal, which has a comparatively small axial thermal expansion coefficient and a high axial electrical conductivity, has high bonding reliability with sealing glass, and is capable of carrying a large current even with a small diameter, and generates little heat when current is applied. [Solution] The composite consists of a [Cr and / or Mo]-Cu composite having a metallic structure in which Cr phases and / or Mo phases are dispersed in a Cu matrix. This [Cr and / or Mo]-Cu composite is a diameter-reduced and drawn material of a powder metallurgy compact. When the cross-sectional structure is observed with an optical microscope, it has an axial cross-sectional structure in which lamellar or linear Cr and / or Mo phases are dispersed in the Cu matrix, and a radial cross-sectional structure in which flake-like, small platelet-like, or granular Cr and / or Mo phases are dispersed in the Cu matrix.

Description

[Technical Field]

[0001] The present invention relates to a lead pin that constitutes a compression-sealing type glass hermetic seal, and an airtight terminal equipped with this lead pin. [Background technology]

[0002] A glass hermetic seal is a seal in which a metal lead pin is airtightly sealed via glass (sealing material) in an insertion hole formed through a metal stem base, and is used, for example, to supply current to electrical equipment or elements housed in an airtight container, or to transfer signals from electrical equipment or elements to the outside. A specific example is an airtight terminal.

[0003] Glass hermetic seals come in two types: matched and compression. The matched seal uses a metal stem base, metal lead pins, and sealing glass with similar thermal expansion coefficients to minimize differential shrinkage between them. The lead pins are chemically sealed via a metal oxide film formed at the interface between the metal and sealing glass. On the other hand, the compression seal utilizes the difference in thermal expansion coefficients between the stem base (metal) and sealing glass to apply compressive stress to the sealing glass and lead pins from the stem base side, mechanically sealing the lead pins. The lead pins and glass are placed in the stem base through-holes, and the glass is heated and melted. When the glass is then cooled and solidified, the stem base compresses the sealing glass and lead pins due to the difference in shrinkage between the stem base and sealing glass, mechanically sealing the lead pins.

[0004] Conventionally, a typical combination of materials for this compression-sealed type is carbon steel such as SC material or SPC material for the stem base, Ni-Fe alloy such as 50% Ni-Fe alloy or Kovar for the lead pin, and soda-based glass for the sealing glass (see, for example, Patent Document 1). In addition to the above, stainless steel (SUS410, SUS430, SUH446, etc.) may be used for the lead pin, and stainless steel (SUS304, SUS410, etc.) or chrome steel for the stem base. This compression-sealed glass hermetic seal has been widely used in hermetic terminals and the like because it can use relatively inexpensive materials. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-27679 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the lead pins of compression-sealed glass hermetic seals have the following technical problem. If the difference in thermal expansion between the lead pin and the sealing glass in the axial direction is large, the axial shear stress generated at the interface between the lead pin and the sealing glass increases. For example, in the case of Kovar (thermal expansion coefficient: 5.3 x 10 -6 / K) has a thermal expansion coefficient of 7.6×10 -6 / K sealing glass (FN-13W, Nippon Electric Glass Co., Ltd.) is used, but 2 × 10 -6 / K. This causes a thermal expansion coefficient difference of about 1 / K. This can lead to problems such as fatigue caused by repeated temperature increases and decreases during use, which can lead to cracks in the sealing glass, reducing the reliability of the bond between the lead pin and the sealing glass. Furthermore, if the lead pin has low axial electrical conductivity, it generates a large amount of heat when electricity is passed through it, making it unusable for applications that carry large currents.

[0007] Among the materials traditionally used for lead pins, Ni-Fe alloys and some stainless steels have relatively small axial thermal expansion differences with the sealing glass. However, all of the materials used for conventional lead pins have low axial electrical conductivity, making them unable to address the issues mentioned above. In particular, electric compressors for EVs and HEVs have become increasingly high-current in recent years. The lead pins of their power connection terminals (airtight terminals with compression-sealed glass hermetic seals) are required to generate sufficiently low heat even when subjected to high currents. However, the conventional lead pins mentioned above cannot meet this requirement. Furthermore, copper-core pins with a 50% Ni-Fe core clad in copper are used to reduce heat generation during high currents, but there are limits to how much heat can be reduced. Furthermore, as electric compressors continue to carry higher currents, the pin diameters will increase, making it impossible to meet the demand for smaller automotive components.

[0008] If the electrical conductivity of the lead pin is low, the power consumption at the lead pin increases, placing a greater strain on the onboard battery. Even higher currents are required for electric vehicles, and existing materials, including copper-core pins, cannot handle the lead pin diameter (e.g., φ3.2 mm) used in airtight terminals, so the lead pin diameter must be made even larger. However, if four times the current current is to be passed through, the lead pin diameter would be φ6.4 mm, which would not only create problems for reducing the weight and size of automotive parts, but would also create a cost problem as the material cost of the lead pin would increase fourfold. As described above, the material for the lead pin is required to have a relatively small axial thermal expansion coefficient, preferably an axial thermal expansion coefficient as close as possible to the thermal expansion coefficient of the sealing glass, and also to have as high an axial electrical conductivity as possible, but to date no metal material that can satisfy these requirements has been known.

[0009] The present invention has been made to solve the problems of the prior art as described above, and its object is to provide a lead pin for a compression-sealed glass hermetic seal which has the properties of a relatively small axial thermal expansion coefficient and high axial electrical conductivity, thereby providing a more reliable bond with the sealing glass than conventional lead pins, and which is capable of carrying a large current despite its small diameter, and which generates little heat when current is passed through it. Another object of the present invention is to provide an airtight terminal equipped with a lead pin having the above-mentioned excellent characteristics and performance, and an electric compressor using this airtight terminal. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to solve the above problems and have come to the following findings. (i) Metallic materials obtained by reducing the area of a [Cr and / or Mo]-Cu composite material obtained by powder metallurgy and then reducing and elongating it into a rod or wire shape (i.e., [Cr and / or Mo]-Cu composites that are elongated powder metallurgical compacts) have a metallic structure in which Cr and / or Mo phases are dispersed in a Cu matrix. However, when cross-sectionally observed with an optical microscope, they have a cross-sectional structure in the elongation direction (axial direction) in which lamellar or linear Cr and / or Mo phases are dispersed in the Cu matrix, and a cross-sectional structure in the transverse direction (radial direction) in which flake-like, small-plate-like, or granular Cr and / or Mo phases are dispersed in the Cu matrix. While rolled Cr-Cu composite sheets (rolled into sheets using flat rolls) have been known, the cross-sectional structure of these metallic materials is completely different from that of the rolled Cr-Cu composite sheets.

[0011] (ii) The metallic material (the [Cr and / or Mo]-Cu composite, which is a diameter-reduced and drawn powder metallurgical compact) with the cross-sectional structure in the stretch direction (axial direction) and transverse direction (radial direction) described above has unique properties (characteristics) that differ from those of the metallic materials conventionally used for lead pins in compression-sealed glass hermetic seals. Specifically, this metallic material has a thermal expansion coefficient in the stretch direction that is less than that in the transverse direction, a relatively small thermal expansion coefficient in the stretch direction, an isotropic thermal expansion coefficient in the transverse direction, and high electrical conductivity in the stretch direction. Furthermore, among these metallic materials, those with further optimized properties can achieve a thermal expansion coefficient in the stretch direction close to that of the sealing glass, and also have significantly higher electrical conductivity in the stretch direction than Ni-Fe alloys, which are commonly used for lead pins.

[0012] Therefore, lead pins made of rod- or wire-shaped metal material (a [Cr and / or Mo]-Cu composite, which is a diameter-reduced and drawn powder metallurgy compact) with the extension direction as the axial direction and the direction perpendicular to the extension as the radial direction have an axial thermal expansion coefficient that is smaller than the radial thermal expansion coefficient, a relatively small axial thermal expansion coefficient, an isotropic radial thermal expansion coefficient, and high axial electrical conductivity. Furthermore, those with further optimized properties can have an axial thermal expansion coefficient close to that of sealing glass, and have significantly higher axial electrical conductivity than Ni-Fe alloys, which are widely used for lead pins.

[0013] Another key feature of this metal material is that its thermal expansion coefficient in the stretching direction (axial direction) can be adjusted by selecting the Cr and / or Mo content of the [Cr and / or Mo]-Cu composite and the area reduction rate during the material's diameter reduction process (diameter reduction and stretching). This allows the axial thermal expansion coefficient of the lead pin to be as close as possible to that of the sealing glass, maximizing the reliability of the bond between the lead pin and the sealing glass, a key issue in compression-sealed glass hermetic seals. Additionally, the axial electrical conductivity of this metal material changes depending on the area reduction rate during diameter reduction and stretching; the greater the area reduction rate, the greater the axial electrical conductivity. Therefore, by adjusting the area reduction rate, the axial electrical conductivity of the lead pin can be appropriately adjusted depending on the application device. (iii) This metallic material can be manufactured relatively easily by subjecting a raw material consisting of a [Cr and / or Mo]-Cu composite (powder metallurgy compact) obtained through a process of sintering powder raw materials to area reduction processing (diameter reduction and elongation processing), thereby reducing and elongating the material into a rod or wire shape. Then, the rod or wire-shaped metallic material manufactured in this manner can be simply cut to a predetermined length to obtain a lead pin (pin substrate).

[0014] The present invention was made based on these findings and has the following gist. [1] A lead pin that constitutes a compression-sealed glass hermetic seal, It consists of a [Cr and / or Mo]-Cu composite having a metal structure in which a Cr phase and / or Mo phase are dispersed in a Cu matrix, The [Cr and / or Mo]-Cu composite is a diameter-reduced and drawn material of a powder metallurgical compact, and when cross-sectionally observed with an optical microscope, it has an axial cross-sectional structure in which lamellar or linear Cr and / or Mo phases are dispersed in a Cu matrix, and a radial cross-sectional structure in which flake-like, small platelet-like, or granular Cr and / or Mo phases are dispersed in a Cu matrix, which is a lead pin for a compression-sealed glass hermetic seal. [2] For the lead pin described in [1] above, the average axial thermal expansion coefficient from 30°C to 450°C is 7.0 to 12.0 × 10 -6 / K, and the radial average thermal expansion coefficient from 30°C to 450°C is 18.0×10 -6 / K or less, and the average axial thermal expansion coefficient from 30°C to 450°C is less than the average radial thermal expansion coefficient from 30°C to 450°C.

[0015] [3] In the lead pin of [1] or [2] above, the electrical conductivity in the axial direction is 20.0 × 10 6 A lead pin of a compression-sealed glass hermetic seal, characterized in that it has a resistance of S / m or more. [4] A lead pin for a compression-sealed glass hermetic seal according to any one of the above [1] to [3], characterized in that the [Cr and / or Mo]-Cu composite has a total Cr and / or Mo content of 35 to 60 mass%. [5] A method for manufacturing a lead pin according to any one of [1] to [4] above, A step (A) of sintering a powder raw material to obtain a material for surface reduction processing comprising a [Cr and / or Mo]-Cu composite; A step (B) of reducing the area of the material obtained in the step (A) and stretching it into a rod or wire shape; The method for producing a lead pin comprises a step (C) of cutting the rod-shaped or wire-shaped material obtained in the step (B) to a predetermined length to obtain a pin material. [6] The method for manufacturing a lead pin according to the above [5], wherein the step (B) includes a step of finishing drawing the material. [7] A method for manufacturing a lead pin, in the manufacturing method of [5] or [6] above, further comprising a step (D) of grinding or polishing the surface of the rod-shaped or wire-shaped material obtained in step (B) or the pin material obtained in step (C).

[0016] [8] In a compression-sealed hermetic terminal, the lead pin is made of a [Cr and / or Mo]-Cu composite having a metal structure in which a Cr phase and / or Mo phase is dispersed in a Cu matrix; The [Cr and / or Mo]-Cu composite is a diameter-reduced and stretched material of a powder metallurgical compact, and when observed through an optical microscope, it has an axial cross-sectional structure in which layered or linear Cr and / or Mo phases are dispersed in a Cu matrix, and a radial cross-sectional structure in which flake-like, small-piece-like, or granular Cr and / or Mo phases are dispersed in a Cu matrix. [9] In the airtight terminal of [8], the lead pin has an axial average thermal expansion coefficient of 7.0 to 12.0 × 10 from 30 ° C to 450 ° C. -6 / K, and the radial average thermal expansion coefficient from 30°C to 450°C is 18.0×10 -6 / K or less, and [average axial thermal expansion coefficient from 30°C to 450°C] < [average radial thermal expansion coefficient from 30°C to 450°C].

[0017]

[10] In the airtight terminal of the above [8] or [9], the lead pin has an axial electrical conductivity of 20.0 × 10 6 An airtight terminal characterized by a resistance of S / m or more.

[11] In the hermetic terminal according to any one of [8] to

[10] above, the [Cr and / or Mo]-Cu composite has a total Cr and / or Mo content of 35 to 60 mass%.

[12] An electric compressor comprising the airtight terminal according to any one of [8] to

[11] above. [Effects of the Invention]

[0018] The lead pins of the present invention have a relatively small axial thermal expansion coefficient (axial thermal expansion coefficient < radial thermal expansion coefficient), an isotropic radial thermal expansion coefficient, and high axial electrical conductivity. Furthermore, among these lead pins, those with further optimized properties can achieve an axial thermal expansion coefficient close to that of sealing glass and have significantly higher axial electrical conductivity than Ni-Fe alloys, which have been widely used in conventional lead pins. Furthermore, the magnitude of the axial thermal expansion coefficient of the lead pins of the present invention can be changed (adjusted) by selecting the Cr and / or Mo content (content) of the [Cr and / or Mo]-Cu composite and the area reduction rate during diameter reduction processing (diameter reduction elongation). This allows the axial thermal expansion coefficient of the lead pin to be as close as possible to that of the sealing glass. In addition, the axial electrical conductivity of the lead pins of the present invention increases with increasing area reduction rate during diameter reduction elongation, so the axial electrical conductivity can be adjusted depending on the application equipment, etc.

[0019] Therefore, the lead pin of the present invention can improve the bonding reliability with the sealing glass, and can carry a large current even with a small diameter, and can reduce the amount of heat generated when current is passed through it. This makes it fully compatible with the ever-increasing current and miniaturization of electric compressors for automobiles, for example. Furthermore, the airtight terminal of the present invention using the lead pin and the electric compressor of the present invention using this airtight terminal each enjoy the effects of the lead pin described above. Therefore, depending on the capacity of the electric compressor, it is possible to realize a very compact airtight terminal by reducing the diameter of the lead pin. [Brief explanation of the drawings]

[0020] [Figure 1] The figure shows an SEM image (left photo) of the surface of a wire-shaped metal material (φ1.2 mm wire made of a 50 mass% Cr-Cu composite) that constitutes a lead pin, which is one example of the present invention, as well as an enlarged photograph (right photo) of the cross-sectional structure in the stretching direction (axial direction) and an enlarged photograph (center photo) of the cross-sectional structure in the direction perpendicular to the stretching direction (radial direction) observed with an optical microscope (magnification 120x). [Figure 2] These are enlarged photographs of the cross-sectional structure in the rolling direction and the cross-sectional structure perpendicular to the rolling direction, observed with an optical microscope, of a metal material (rolled plate material of 50 mass% Cr-Cu composite) obtained by infiltrating Cu into a Cr sintered body and rolling it into a plate using a flat roll. [Figure 3] 3A and 3B are schematic diagrams showing a compression-sealing type glass hermetic seal, with FIG. 3A being a plan view and FIG. 3B being a cross-sectional view taken along line AA in FIG. 3A. [Figure 4] 1A and 1B are diagrams showing a cross section of a lead pin according to the present invention, with the upper drawing showing a radial cross section of the lead pin and the lower drawing showing an axial cross section. [Figure 5] 5A and 5B are schematic diagrams of a compression-sealed glass hermetic seal used to examine the bonding reliability when the lead pin of the present invention is applied to a "compression-sealed glass hermetic seal provided in an airtight terminal" (conceptual diagrams showing the dimensions and thermal expansion coefficients of the constituent parts, the compressive stress within the seal, etc.), where FIG. 5A is a schematic vertical cross-sectional view of the entire seal, FIG. 5B is a schematic plan view of the same, and FIG. 5C is a schematic plan view of the sealing glass. [Figure 6] 6A and 6B are schematic diagrams of a compression-sealed glass hermetic seal used to examine the bonding reliability when the lead pin of the present invention is applied to a "compression-sealed glass hermetic seal provided in an airtight terminal" (conceptual diagrams showing the dimensions and thermal expansion coefficients of the constituent parts, the compressive stress within the seal, etc.), where FIG. 6A is a schematic vertical cross-sectional view of the entire seal, FIG. 6B is a schematic plan view of the housing (stem base) and sealing glass, and FIG. 6C is a schematic plan view of the sealing glass and lead pin. DETAILED DESCRIPTION OF THE INVENTION

[0021] <Lead pin of the present invention> The lead pin of the present invention is a lead pin that constitutes a compression-sealed glass hermetic seal, and is made of a [Cr and / or Mo]-Cu composite having a metal structure in which a Cr phase and / or Mo phase is dispersed in a Cu matrix. This [Cr and / or Mo]-Cu composite is a diameter-reduced, drawn material of a powder metallurgy compact, and is characterized by having, when observed in cross-sectional structure with an optical microscope (for example, 120x magnification), an axial cross-sectional structure in which lamellar or linear Cr and / or Mo phases are dispersed in the Cu matrix, and a radial cross-sectional structure in which flake-like, small platelet-like, or granular Cr and / or Mo phases are dispersed in the Cu matrix.

[0022] Generally, lead pins have a surface treatment film such as Ni plating on the surface of the pin base material (pin body), but in this invention, the term "lead pin" refers to the "pin base material" excluding such a surface treatment film. The same applies to the inventions relating to the airtight terminal and electric compressor described below. In the present invention, the term "Cr and / or Mo" refers to a Cr-Cu composite having a metal structure in which a Cr phase is dispersed in a Cu matrix, a Mo-Cu composite having a metal structure in which a Mo phase is dispersed in a Cu matrix, and a Cr·Mo-Cu composite having a metal structure in which a Cr phase and a Mo phase are dispersed in a Cu matrix.

[0023] In the present invention, the term "powder metallurgy compact" refers to a compact obtained by applying a powder metallurgy method, and therefore includes compacts obtained in step (A) of the manufacturing method described below, such as (i) a compact obtained by step (a1) of sintering a compact (green compact) of powder raw materials to form a sintered compact, and step (a2) of subjecting the sintered compact to Cu infiltration and / or densification treatment, and (ii) a compact obtained by subjecting the powder raw materials to spark plasma sintering (SPS sintering) or hot press sintering. Furthermore, the term "diameter-reduced and elongated material of powder metallurgy compact" refers to a material obtained by reducing and elongating the powder metallurgy compact described above through area-reducing processing (diameter-reducing and elongating processing). In the present invention, "a lamellar or linear Cr phase and / or Mo phase is dispersed in a Cu matrix" includes the case where both a "lamellar Cr phase and / or Mo phase" and a "linear Cr phase and / or Mo phase" are dispersed (mixed) in the Cu matrix. Similarly, "a flake-like, small platelet-like, or granular Cr phase and / or Mo phase is dispersed in a Cu matrix" includes the case where two or more of a "flake-like Cr phase and / or Mo phase," a "small platelet-like Cr phase and / or Mo phase," and a "granular Cr phase and / or Mo phase" are dispersed (mixed) in the Cu matrix.

[0024] The metallic material constituting the lead pin of the present invention is obtained by subjecting a raw material consisting of a [Cr and / or Mo]-Cu composite (powder metallurgy compact) obtained through a sintering process of powder raw materials to area reduction (diameter-reducing and elongation processing) and elongating it into a rod or wire shape. The elongation direction is the axial direction and the direction perpendicular to the elongation is the radial direction. Therefore, the lead pin of the present invention has the characteristic axial and radial cross-sectional structure described above, in which Cr and / or Mo phases are formed in which Cr particles and / or Mo particles dispersed in a Cu matrix are elongated into needle-like or rod-like shapes in the axial direction. Furthermore, the [Cr and / or Mo]-Cu composite having such a characteristic axial and radial cross-sectional structure has unique properties, as described below, particularly properties suitable for lead pins in compression-sealed glass hermetic seals. Such a metallic material (a [Cr and / or Mo]-Cu composite) has not been previously known.

[0025] The radial cross-sectional shape of the rod-shaped or wire-shaped metal material constituting the lead pin of the present invention is not particularly limited, but is usually a circular or polygonal cross-section (for example, a hexagonal, octagonal, or hexadecagonal cross-section). Note that there is no strict distinction between rod-shaped materials (rod material) and wire-shaped materials (wire material), but generally, wire-shaped materials (wire material) refer to materials that can be wound, and rod-shaped materials (rod material) refer to materials that cannot be wound. As described above, this rod-shaped or wire-shaped metal material is obtained by subjecting a [Cr and / or Mo]-Cu composite (powder metallurgy compact) obtained by powder metallurgy to area reduction processing (diameter-reducing and elongating processing) to reduce and elongate it into a rod-shaped or wire-shaped material. The lead pin (pin substrate) of the present invention is obtained by cutting this diameter-reduced and elongated metal material to a predetermined length (however, surface grinding and polishing may be performed as a finishing process before or after this cutting). In the present invention, when referring to "rod-shaped or wire-shaped metal material," "rod-shaped or wire-shaped material," "rod-shaped or wire-shaped raw material," or "(the material) is reduced in diameter and drawn into a rod or wire shape," "rod-shaped" means "rod-shaped," and similarly, "wire-shaped" means "wire-shaped."

[0026] Figure 1 shows an SEM image (left photo) of the surface of a wire-shaped metal material (φ1.2 mm wire made of a 50 mass% Cr-Cu composite) constituting a lead pin, which is one example of the present invention. It also shows an enlarged photograph (right photo) of the cross-sectional structure in the stretching direction (axial direction) and a magnified photograph (center photo) of the cross-sectional structure in the direction perpendicular to the stretching direction (radial direction) observed with an optical microscope (120x magnification). In the cross-sectional structure in the stretching direction and the direction perpendicular to the stretching direction (axial and radial directions), the dark areas represent Cr phases dispersed in the Cu matrix (light areas). The manufacturing conditions for this metal material were as follows: a rectangular prism-shaped blank (9 mm in diameter) for area reduction was subjected to swaging followed by combined roll rolling (diameter reduction and elongation), and then finish drawing (CRD) to reduce the area (diameter reduction and elongation) to an outer diameter of φ1.2 mm.

[0027] This metallic material is a material obtained by reducing the area of a Cr-Cu composite (powder metallurgy compact) obtained by powder metallurgy as described above, and then reducing and elongating it into a rod or wire shape. Therefore, the Cr particles dispersed in the Cu matrix of the material (powder metallurgy compact) are elongated into needle-like or rod-like shapes (not the "flat" shapes of the plate-rolled material shown in FIG. 2 ). As a result, the cross-sectional structure shown in FIG. 1 is obtained. Specifically, the cross-sectional structure in the elongation direction (axial direction) observed with an optical microscope is a cross-section of the elongated needle-like or rod-like Cr phase in the elongation direction, resulting in a layered or linear Cr phase dispersed in the Cu matrix. This layered (also referred to as "band-like") or linear Cr phase exists in an elongated state along the elongation direction (axial direction) of the material, and typically includes a mixture of layered Cr phases with a certain width and thin linear Cr phases. Among these, the layered structures with a certain width are considered to be Cr phases formed by the elongation and coalescence of multiple adjacent Cr particles for the reasons described below. Even in the cross-sectional structure in the elongation direction (axial direction) of the material shown in Figure 1, the Cr phases are a mixture of layered structures with a certain width and thin linear structures elongated in the elongation direction (axial direction) of the material, and dispersed in the Cu matrix. On the other hand, in the cross-sectional structure in the direction perpendicular to the elongation direction (radial direction) observed with an optical microscope, the above-mentioned needle- or rod-shaped elongated Cr phases are cross-sectioned in the direction perpendicular to the elongation direction, resulting in the dispersion of thin, small, or granular Cr phases in the Cu matrix. Usually, the Cr phase in this cross-sectional structure is a mixture of thin, small, and granular Cr phases. The reason why the Cr phase appears flake-like or small in the cross section perpendicular to the stretching direction is thought to be that when the raw material (powder metallurgy compact) is stretched to elongate needle- or rod-like shapes by reducing its diameter, the Cr phase distribution in the stretching direction becomes uneven, causing some of the Cr phase particles to approach, contact, or coalesce. Even in the cross section structure perpendicular to the stretching direction (radial direction) in Figure 1, fine-grained Cr phase (flake-like, flake-like, or granular Cr phase) is relatively uniformly dispersed in the Cu matrix. This flake-like, flake-like, or granular Cr phase is a cross section perpendicular to the stretching direction (radial direction) of the Cr phase that has been elongated to elongate needle- or rod-like shapes, as described above. FIG. 1 shows the cross-sectional structure in the stretching direction and perpendicular to the stretching direction (axial and radial directions) of a wire-shaped metal material made of a Cr-Cu composite (a φ1.2 mm wire made of a 50 mass% Cr-Cu composite), which is one example of the present invention. However, the metal materials of the present invention made of a Mo-Cu composite or a Cr-Mo-Cu composite also have similar cross-sectional structures in the stretching direction and perpendicular to the stretching direction (axial and radial directions).

[0028] For comparison, Fig. 2 shows the cross-sectional structures in the rolling direction and transverse to the rolling direction observed with an optical microscope for a rolled sheet of a 50 mass% Cr-Cu composite, i.e., a metal material obtained by infiltrating a Cr sintered body with Cu and rolling it into a sheet using a flat roll. In the case of this rolled sheet of Cr-Cu composite, there was no significant difference between the cross-sectional structures in the rolling direction and transverse to the rolling direction. In both the rolling direction and transverse to the rolling direction, the 75% reduction exhibited a Cr phase dispersed in a quasi-mesh structure in the Cu matrix, while the 98% reduction exhibited a unidirectionally elongated Cr phase dispersed in a flat (quasi-fibrous) structure in the Cu matrix. Comparing this to Fig. 2 reveals that the metallic material of Fig. 1 constituting the lead pin of the present invention has a very distinctive cross-sectional structure in the elongation direction and transverse to the elongation direction (axial and radial directions). In particular, with regard to the cross-sectional structure perpendicular to the stretching direction, the plate-rolled material in FIG. 2 has a morphology in which the Cr phase is thinly elongated into a flat shape (quasi-fibrous shape), whereas the material of the present invention in FIG. 1 has a morphology in which the Cr phase is dispersed in the form of fine flakes, small pieces, or particles (cross-sectional shape perpendicular to the stretching direction of the Cr phase that is elongated into a needle-like or rod-like shape in the stretching direction), and thus presents a completely different morphology.

[0029] The Cr-Cu composite rolled sheet shown in Figure 2 was developed for use in heat sinks to be bonded between semiconductors or ceramics with low thermal expansion coefficients and the sheet surface, and because it has the cross-sectional structure described above, the thermal expansion coefficient in the sheet surface directions (rolling direction and direction perpendicular to the rolling) is small, but the thermal expansion coefficient in the sheet thickness direction is large. Therefore, if a shaft with its axial direction aligned with the rolling direction is cut out from this rolled sheet and used as a lead pin for a compression-sealed glass hermetic seal, the thermal expansion coefficient in the pin radial direction will be anisotropic, resulting in a large difference in thermal expansion between the lead pin and the sealing glass in one direction of the pin radial cross section, causing cracks in the sealing glass and other problems that prevent sufficient bonding reliability. In contrast, the metal material that constitutes the lead pin of the present invention has unique properties (characteristics) that are completely different from those of conventionally known metal materials, as will be described later. These properties are extremely suitable for lead pins, and do not present any of the problems seen in the above-mentioned Cr-Cu composite plate rolled material (Figure 2).

[0030] FIG. 3 is a schematic diagram showing a compression-sealed glass hermetic seal in which the lead pin of the present invention is used, where FIG. 3(a) is a plan view and FIG. 3(b) is a cross-sectional view taken along line AA in FIG. 3(a). This compression-sealed glass hermetic seal is composed of a stem base 1, a lead pin 2, sealing glass 3, etc., and is a seal in which the lead pin 2 is airtightly sealed in an insertion hole 4 formed through the stem base 1 via the sealing glass 3 (sealing material). Lead pins are also called leads, metal pins, pins, feedthroughs, etc., and have traditionally been made from materials such as Fe-Ni alloys, Kovar, stainless steel (SUS410, SUS430, SUH446, etc.), etc. The lead pins of the present invention, made from the above-mentioned metal materials, can be used as substitutes for these conventional products and exhibit superior performance compared to them.

[0031] Figure 4 shows a schematic cross section of a lead pin of the present invention, with the upper figure showing a radial cross section and the lower figure showing an axial cross section. This figure shows a schematic cross section of the Cr and / or Mo phases that are formed when Cr particles and / or Mo particles dispersed in a Cu matrix are stretched into needle-like or rod-like elongated shapes in the stretching direction. In the axial cross section (lower diagram) of Figure 4, the short lines represent "layered or linear Cr phases and / or Mo phases" dispersed in the Cu matrix, which corresponds to the cross-sectional structure in the photograph on the right side of Figure 1. In addition, in the radial cross section (upper diagram) of Figure 4, the dots represent "fine, small, or granular Cr phases and / or Mo phases" dispersed in the Cu matrix, which corresponds to the cross-sectional structure in the central photograph of Figure 1. As shown in this drawing, the lead pin of the present invention has the unique axial and radial cross-sectional structure described above.

[0032] As mentioned above, the lead pins that make up a compression-sealed glass hermetic seal are required to have (i) a relatively small axial thermal expansion coefficient and be as close as possible to the sealing glass to ensure reliable bonding with the sealing glass, and (ii) be able to carry a large current despite their small diameter and generate little heat when current is passed through them, i.e., have high axial electrical conductivity. The lead pin of the present invention has the above-described axial and radial cross-sectional structure, and therefore has unique properties (characteristics) that differ from those of lead pins of conventional compression-sealed glass hermetic seals. Specifically, the lead pin of the present invention has a relatively small axial thermal expansion coefficient (axial thermal expansion coefficient < radial thermal expansion coefficient), and yet high axial electrical conductivity. Furthermore, among these lead pins, those with further optimized properties as described below can achieve an axial thermal expansion coefficient close to that of sealing glass, and yet have significantly higher axial electrical conductivity than Ni-Fe alloys, which are widely used for lead pins. Furthermore, the lead pin of the present invention is a diameter-reduced, drawn material of a powder metallurgy compact, and has the above-described cross-sectional structure in the drawing direction (axial) and the direction perpendicular to the drawing direction (radial direction). Therefore, its radial thermal expansion coefficient is the same in all radial directions, and its radial thermal expansion coefficient is isotropic. According to the examples described below, the lead pins (invention examples) of the present invention all have a radial thermal expansion coefficient greater than the axial thermal expansion coefficient, which is a relatively low axial thermal expansion coefficient close to that of the sealing glass (however, the thermal expansion coefficient differs depending on the type of glass). Furthermore, the lead pins (invention examples) of the present invention have significantly higher axial electrical conductivity than the 50.5 mass% Ni-Fe (comparative example No. 30) that has been widely used in conventional lead pins.

[0033] As described above, the lead pin of the present invention generally has properties not found in conventional lead pins, such as "axial thermal expansion coefficient < radial thermal expansion coefficient, relatively small axial thermal expansion coefficient, isotropic radial thermal expansion coefficient, and high axial electrical conductivity." Furthermore, the lead pin also has the following significant features. First, this lead pin has the advantage that the magnitude of the axial thermal expansion coefficient can be changed (adjusted) by selecting the blending ratio (content) of Cr and / or Mo in the [Cr and / or Mo]-Cu composite and the area reduction rate during diameter reduction and elongation of the material by area reduction processing (diameter-reducing and elongation processing). Specifically, for a given area reduction rate during diameter reduction and elongation of the material, the higher the blending ratio of Cr and / or Mo, and, for a given blending ratio of Cr and / or Mo, the smaller the axial thermal expansion coefficient can be. Furthermore, for a given blending ratio of Cr and / or Mo, the larger the area reduction rate during diameter reduction and elongation, up to about 97%. This allows the axial thermal expansion coefficient of the lead pin to be as close as possible to the thermal expansion coefficient of the sealing glass, maximizing the reliability of the connection between the lead pin and the sealing glass, which is an issue with compression-sealed glass hermetic seals.

[0034] This will be explained using the examples described later. For example, lead pins Nos. 5, 10, 15, and 20 (invention examples) in the examples are made of Cr-Cu composites with a 90.3% area reduction and different Cr blending ratios, and the axial thermal expansion coefficient decreases as the Cr blending ratio increases. Lead pins Nos. 24 and 29 (invention examples) are made of Mo-Cu composites with a 97.6% area reduction and different Mo blending ratios, and lead pins Nos. 37 and 39 (invention examples) are made of Mo-Cu composites with a 80% area reduction and different Mo blending ratios, and in all cases the axial thermal expansion coefficient decreases as the Mo blending ratio increases. On the other hand, for example, lead pins Nos. 7 to 12 (invention examples) are made of Cr-Cu composites with a 45 mass% Cr content and different area reduction ratios, while lead pins Nos. 26 to 29 (invention examples) are made of Mo-Cu composites with a 40 mass% Mo content and different area reduction ratios. In all cases, the axial thermal expansion coefficient decreases with increasing area reduction ratio. This allows the axial thermal expansion coefficient of the lead pin to be as close as possible to the thermal expansion coefficient of the sealing glass, depending on the thermal expansion coefficient of the sealing glass. This maximizes the bonding reliability between the lead pin and the sealing glass, which is an issue in compression-sealed glass hermetic seals. In particular, as described below, a positive and as small value of τ3 / P2 (= [axial compressive shear stress τ3 acting from the lead pin to the sealing glass interface] / [radial compressive stress P2 from the sealing glass to the lead pin]) is preferable because it increases the bonding reliability between the lead pin and the sealing glass. It is possible to adjust the axial thermal expansion coefficient of the lead pin (to approach the thermal expansion coefficient of the sealing glass) to achieve such a τ3 / P2.

[0035] Furthermore, the axial electrical conductivity of the lead pins of the present invention varies depending on the area reduction rate during diameter reduction and elongation. For example, when the Cr and / or Mo content is the same, the axial electrical conductivity increases with increasing area reduction rate up to approximately 97% during diameter reduction and elongation. For example, in the previously listed examples, lead pins Nos. 7 to 12 (inventive examples with a Cr content of 45% by mass) and lead pins Nos. 26 to 29 (inventive examples with a Mo content of 40% by mass), the axial electrical conductivity increases with increasing area reduction rate. Therefore, by changing the area reduction rate, the axial electrical conductivity of the lead pin can be appropriately adjusted depending on the application equipment, etc. As is clear from the examples, the axial electrical conductivity also changes depending on the component composition of the lead pin (the Cr and / or Mo content), and the lower the Cr and / or Mo content, the higher the axial electrical conductivity.

[0036] As for the thermal properties of the rod-shaped or wire-shaped metal material constituting the lead pin of the present invention, the thermal expansion coefficient in the stretching direction (axial direction) is smaller than the thermal expansion coefficient in the direction perpendicular to the stretching direction (radial direction) as described above. This is thought to be because the shear stress at the interface between Cu and the Cr phase and / or Mo phase that has been stretched into an elongated, needle-like or rod-like shape by the diameter-reducing stretching process suppresses the expansion of Cu in the stretching direction. However, since the range affected by the shear stress of one Cr phase and / or Mo phase in the cross section perpendicular to the stretching direction is limited, the higher the density of the Cr phase and / or Mo phase in the cross section perpendicular to the stretching direction, i.e., the higher the blending ratio (content) of Cr and / or Mo, the smaller the thermal expansion coefficient in the stretching direction tends to be. Furthermore, the longer the elongation length of the Cr and / or Mo phase in the elongation direction, the greater the shear stress. Therefore, as described below, if the area reduction rate is large when manufacturing the lead pin (rod-shaped or wire-shaped metal material) of the present invention, the elongation length of the Cr and / or Mo phase in the elongation direction increases, and the elongation-direction thermal expansion coefficient decreases. That is, the larger the area reduction rate, the smaller the elongation-direction thermal expansion coefficient. The thermal expansion coefficient in the direction perpendicular to the elongation direction also increases with the area reduction rate. This is because the larger the area reduction rate, the smaller the diameter of the Cr and / or Mo phase in the direction perpendicular to the elongation direction, and the smaller the restraining force of Cu in the direction perpendicular to the elongation direction. From the above, it can be seen that the thermal expansion coefficients in the elongation direction (axial direction) and the direction perpendicular to the elongation direction (radial direction) can be adjusted by selecting the Cr and / or Mo compounding ratio (content) and the area reduction rate during diameter reduction elongation of the material. In addition, the electrical conductivity in the elongation direction (axial direction) increases as the area reduction rate increases. This is thought to be because, as the area reduction rate increases, the Cr phase and / or Mo phase stretched in the elongation direction causes the structure of the Cu phase to also stretch in the elongation direction, and current flows preferentially in the elongation direction.

[0037] As described above, the lead pin of the present invention has the characteristics that the axial thermal expansion coefficient is smaller than the radial thermal expansion coefficient, the axial thermal expansion coefficient is relatively small, the radial thermal expansion coefficient is isotropic, and the axial electrical conductivity is high. However, the optimum thermal properties are an average axial thermal expansion coefficient of 7.0 to 12.0 × 10 from 30 ° C to 450 ° C. -6 / K, and the radial average thermal expansion coefficient from 30°C to 450°C is 18.0×10 -6 / K or less, and it is preferable that the average axial thermal expansion coefficient from 30°C to 450°C is less than the average radial thermal expansion coefficient from 30°C to 450°C. The average radial thermal expansion coefficient of the lead pin is 18.0×10 -6 / K or less, it is considered possible for the lead pin to receive compressive stress from the sealing glass (see "Reference Examples" in Tables 1 and 3 below), so there is no particular problem. However, if the difference in coefficient of thermal expansion between the lead pin and the sealing glass is too large, the compressive force from the sealing glass will be small, which is not desirable. Therefore, it is recommended to set the coefficient of thermal expansion between the lead pin and the sealing glass to 15.0 × 10 -6 / K or less may be preferred.

[0038] The average axial thermal expansion coefficient from 30°C to 450°C is 7.0 to 12.0 x 10 -6 / K is particularly effective in achieving the above-mentioned effects. That is, if the average axial thermal expansion coefficient is within the above range, it is close to the thermal expansion coefficient of the sealing glass, which is preferable because it makes it easier to achieve bonding reliability with the sealing glass. Furthermore, the axial thermal expansion coefficient can be appropriately adjusted (selected) within the above range depending on the thermal expansion coefficient of the sealing glass used. As mentioned above, the average axial thermal expansion coefficient can be adjusted by changing the component composition of the metal material (the blending ratio of Cr and / or Mo) or the area reduction rate during diameter reduction and elongation of the material. Regarding the point that the radial thermal expansion coefficient is greater than the axial thermal expansion coefficient, which is a characteristic of the thermal properties of the lead pin of the present invention, in the examples (invention examples) described later, the difference between the [average axial thermal expansion coefficient from 30°C to 450°C] and the [average radial thermal expansion coefficient from 30°C to 450°C] is 2.0 × 10 -6 / K or higher.

[0039] The reason why the average thermal expansion coefficient in the axial and radial directions is defined as the average thermal expansion coefficient from 30°C to 450°C is as follows: Sealing glass with a glass transition point (Tg) in the range of approximately 410 to 560°C is used, and the volume of sealing glass is determined at a temperature near the glass transition point -30°C. Therefore, the volume of sealing glass with a glass transition point of approximately 410 to 560°C is determined at a temperature of approximately 380 to 530°C. However, since the average thermal expansion coefficient in this temperature range does not change significantly depending on the temperature, 450°C, which is approximately the midpoint between 380 and 530°C, is used as a representative value, and the "average thermal expansion coefficient from 30°C to 450°C" is defined.

[0040] Furthermore, the lead pin of the present invention has an optimal axial electrical conductivity of 20.0×10 6 S / m or more. The axial electrical conductivity is preferably 20.0×10 6 S / m or more is particularly effective in achieving the above-mentioned effects. 6 If "S / m or more" is converted to volume resistivity, which is the reciprocal of electrical conductivity, it becomes "volume resistivity of 5.0 μΩ·cm or less." Therefore, in terms of volume resistivity, it is preferable that the axial volume resistivity be 5.0 μΩ·cm or less. High axial electrical conductivity is a particularly useful property for lead pins, but the axial electrical conductivity is 20.0×10 6 A level of S / m or more is a significantly higher axial electrical conductivity than Ni-Fe alloys, which have been widely used in conventional lead pins, and it is possible to pass a large current through a small-diameter lead pin, with the effect of significantly reducing the amount of heat generated during current flow. As will be shown in the examples below, the axial electrical conductivity of 50.5 mass% Ni-Fe (comparative example No. 30), which has been conventionally used in lead pins, is 2.81 × 10 6 S / m, whereas the axial electrical conductivity of the lead pin of the present invention is one order of magnitude larger, demonstrating that a significantly higher electrical conductivity can be obtained. As mentioned above, the axial electrical conductivity of this lead pin can also be adjusted by selecting the component composition of the metal material (the blending ratio of Cr and / or Mo) and the area reduction rate when the material is reduced in diameter and stretched.

[0041] As described above, the lead pin of the present invention has an axial thermal expansion coefficient that is smaller than the radial thermal expansion coefficient, a relatively small axial thermal expansion coefficient, an isotropic radial thermal expansion coefficient, and high axial electrical conductivity, which results in high bonding reliability with the sealing glass, and further enables the passage of large currents even with a small diameter, reducing the amount of heat generated during current passage. This makes it possible to fully accommodate, for example, the further increase in current and miniaturization of electric compressors for automobiles. Here, the characteristics of the lead pin of the present invention are determined as follows. The axial and radial thermal expansion coefficients are measured using a push rod displacement detection method, and the average axial and radial thermal expansion coefficients from 30°C to 450°C are calculated by measuring the axial and radial thermal expansion coefficients using the push rod displacement detection method, finding the difference in the amount of expansion at 30°C and 450°C, and dividing this value by the temperature difference of 420°C (= 450°C - 30°C). The electrical conductivity in the axial direction is measured by a DC four-terminal method (measurement temperature: room temperature, atmosphere: air) using a commercially available electrical resistance measuring device.

[0042] The lead pin of the present invention has the above-mentioned unique properties (characteristics) due to its characteristic axial (stretching direction) and radial (direction perpendicular to stretching) cross-sectional structure as shown in Figure 1. Therefore, although the Cr and / or Mo content (blending ratio) of the [Cr and / or Mo]-Cu composite constituting the lead pin of the present invention is not particularly limited, a Cr and / or Mo content of 35 to 60 mass% in total is particularly effective for achieving the above-mentioned thermal properties. This is because a low Cr and / or Mo content (total) reduces the restraining force of the Cr and / or Mo phase on Cu, making it difficult to reduce the thermal expansion coefficient of the material, particularly the axial thermal expansion coefficient. On the other hand, a high Cr and / or Mo content (total) reduces the workability of the material (raw material), making it difficult to reduce the area (diameter-reducing elongation) into a rod or wire shape and making it difficult to increase the axial electrical conductivity.

[0043] When comparing the Cr (Cr phase) and Mo (Mo phase) that are added to Cu in the [Cr and / or Mo]-Cu composite that constitutes the lead pin of the present invention, there are the following tendencies: (i) Cr provides better material workability (rollability, etc.) than Mo, (ii) Mo is more likely to increase axial electrical conductivity than Cr, and (iii) Mo is more likely to reduce axial thermal expansion coefficient than Cr (the above tendencies of (ii) and (iii) can be confirmed in the examples described below). Therefore, for example, in a Cr·Mo-Cu composite, the thermal properties can be balanced and optimally optimized by adjusting the contents and ratios of Cr and Mo depending on the required thermal properties. The diameter of the lead pin varies depending on the glass hermetic seal to be used, but is usually about φ0.1 to 6 mm. Usually, the lead pin is subjected to a surface treatment such as Ni plating.

[0044] Next, a method for manufacturing a lead pin according to the present invention will be described. First, the rod-shaped or wire-shaped metal material constituting the lead pin of the present invention can generally be produced by subjecting a raw material consisting of a [Cr and / or Mo]-Cu composite (powder metallurgy compact) obtained through a process of sintering a powder raw material to area-reducing processing (diameter-reducing and elongating processing) to reduce and elongate it into a rod or wire. The rod-shaped or wire-shaped metal material ([Cr and / or Mo]-Cu composite) produced through this series of processes has the above-mentioned structure in which the Cr and / or Mo phases in the Cu matrix are elongated in the axial direction (longitudinal direction) into needle-like or rod-like elongated shapes, i.e., a cross-sectional structure in the elongation direction (axial direction) in which lamellar or wire-shaped Cr and / or Mo phases are dispersed in the Cu matrix, and a cross-sectional structure in the direction perpendicular to the elongation direction (radial direction) in which flake-like, small-platelet-like, or granular Cr and / or Mo phases are dispersed in the Cu matrix.

[0045] Therefore, a preferred method for manufacturing a lead pin of the present invention includes step (A) of obtaining a material for surface-reduction processing consisting of a [Cr and / or Mo]-Cu composite through a step of sintering a powder raw material, step (B) of subjecting the material obtained in step (A) to surface-reduction processing (diameter-reducing and elongating processing) to reduce and elongate it into a rod-like or wire-like shape, and step (C) of cutting the rod-like or wire-like material obtained in step (B) to a predetermined length to obtain pin material. As will be described later, step (A) also includes Cu infiltration or densification treatment after sintering the powder raw material, and spark plasma sintering or hot press sintering of the powder raw material.

[0046] In step (A), the material for area reduction can be obtained in various ways, but the basic ways include the following (i) and (ii). Each way may be carried out according to a conventional method. (i) A material for surface reduction processing consisting of a [Cr and / or Mo]-Cu composite is obtained through a process (a1) of sintering a compact (pressed powder) of powder raw material to form a sintered body, and a process (a2) of subjecting this sintered body to Cu infiltration and / or densification treatment. (ii) By subjecting the powder raw material to a spark plasma sintering (SPS sintering) or hot press sintering process, a material for surface reduction processing consisting of a [Cr and / or Mo]-Cu composite is obtained. In the above embodiment (i), in step (a1), the powder raw material is filled into a mold and molded in a conventional manner, and the molded body (green compact) is sintered in a predetermined atmosphere to form a sintered body. Next, in step (a2), the sintered body is subjected to at least one of Cu infiltration and densification treatment to prepare a material for area reduction processing.

[0047] In the Cu infiltration of a sintered body, for example, a Cu plate or Cu powder for Cu infiltration may be placed on a compact of powder raw material, and the compact may be first heated to a sintering temperature to sinter, and then the temperature may be raised to the Cu infiltration temperature to perform Cu infiltration. Note that the Cu infiltration body obtained in this process is preferably subjected to surface grinding (for example, surface grinding using a milling machine or grinding wheel) to remove excess pure Cu remaining on the surface. The densification treatment is intended to densify a porous sintered body. There are no particular limitations on the type of treatment, but typical examples include hot extrusion, HIP treatment, hot pressing, and spark plasma treatment (SPS treatment), and one or more of these can be performed. When the sintered body is not subjected to Cu infiltration, it is preferable to perform this densification treatment to densify the sintered body. On the other hand, the sintered body can be densified by Cu infiltration, but the densification treatment described above may be performed after this Cu infiltration. In HIP (hot isostatic pressing), a densification process, the sintered body is pressurized (hydrostatically) and heated in a pressure vessel using an inert gas as the pressure medium. In hot pressing, the sintered body is pressurized while being heated in a mold. In spark plasma processing (SPS), the sintered body is pressurized while being heated by pulse current in a mold.

[0048] In the above embodiment (ii), a dense sintered body can be obtained by spark plasma sintering (SPS sintering) or hot press sintering, and can be used as is as a material for area reduction processing. In spark plasma sintering, powder raw materials are filled into a mold and sintered by pulse current heating while being pressurized, while in hot press sintering, powder raw materials are placed in a mold and sintered while being heated and pressurized. Therefore, specific embodiments of step (A) include, for example, the following (A) to (D), but are not limited to these.

[0049] (a) Cr powder and / or Mo powder are molded, or a mixture of Cr powder and / or Mo powder and Cu powder is molded, and this molded body is sintered to form a sintered body, which is then infiltrated with Cu to obtain a material for surface reduction processing made of a [Cr and / or Mo]-Cu composite. (a) A mixed powder of Cr powder or / and Mo powder and Cu powder is molded, and this molded body is sintered to form a sintered body. This sintered body is then subjected to a densification treatment, such as hot extrusion, HIP treatment, hot pressing, or spark plasma treatment (SPS treatment), to obtain a material for area reduction processing consisting of a [Cr and / or Mo]-Cu composite. (c) Cr powder and / or Mo powder is molded, or a mixture of Cr powder and / or Mo powder and Cu powder is molded, and this molded body is sintered to form a sintered body. Cu is infiltrated into this sintered body, and then a densification treatment is performed using one of hot extrusion, HIP treatment, hot pressing, and spark plasma treatment (SPS treatment), to obtain a material for area reduction processing made of a [Cr and / or Mo]-Cu composite. (d) A mixed powder of Cr powder or / and Mo powder and Cu powder is subjected to spark plasma sintering or hot press sintering to obtain a material for surface reduction processing made of a [Cr and / or Mo]-Cu composite. The material for area reduction obtained in step (A) is usually a round bar or a square bar (for example, having a polygonal cross section).

[0050] In step (B), any processing method can be used as long as it is possible to reduce the area of the material (diameter-reducing and drawing processing) and draw it into a rod or wire shape. For example, it can be performed by combining one or more of roll rolling, swaging, and hot extrusion, and further, it may be possible to perform finish drawing (wire drawing) afterwards. Rolling can be, for example, grooved roll rolling or combined roll rolling. Grooved roll rolling is a process in which a material (round bar, square bar, etc.) is reduced in area (diameter-reducing and elongating) into a rod or wire shape using grooved rolls. Combined roll rolling is a process in which a material (round bar, square bar, etc.) is reduced in area (diameter-reducing and elongating) into a rod or wire shape using grooved rolls with multiple stands (for example, 20 stands or more). Swaging is a type of compression process (cold forging) in which a die is used to crush a material in the radial direction, reducing the outer diameter and extending the length (diameter reduction and extension). For example, the die is rotated to squeeze the material and extend the length (diameter reduction and extension). In hot extrusion, the material is placed in a container and a ram pushes the material through a die hole.

[0051] When finish drawing (wire drawing) is performed, it is usually performed as a final area reduction process (diameter reduction and elongation process). However, for example, when a rod-shaped body with a relatively large diameter is to be obtained, this finish drawing process may not be performed. In the drawing process, known processes such as simple drawing (wet process, dry process) and roller die drawing (CRD) can be used. Although there is no particular limit to the total area reduction rate of the material in step (B), if the area reduction rate is too small, it becomes difficult to obtain the lead pin structure of the present invention, so the total area reduction rate of the material in step (B) is desirably 60% or more. Also, although there is no particular upper limit to the total area reduction rate of the material in step (B), there is a practical upper limit depending on the compounding ratio of Cr and / or Mo, the manufacturing equipment (processing means for area reduction), etc. Here, the area reduction rate (cross-sectional area reduction rate) is calculated as follows: Area reduction rate (%) = [(ab) / a] × 100, where a is the radial cross-sectional area of the material before the area reduction process in step (B) and b is the radial cross-sectional area of the material after the process (B).

[0052] In step (C), the rod-shaped or wire-shaped material obtained in step (B) is cut to a predetermined length to obtain pin material that will become lead pins. A wire cutting machine, for example, can be used to cut the material (cutting in the radial direction of the material). The pin material obtained in step (C) becomes lead pins (pin substrate) either as is or after necessary processing. Typically, the lead pins (pin substrate) are subjected to a surface treatment such as Ni plating. The surface of the rod-shaped or wire-shaped metal material obtained in step (B) may develop scratches or irregularities due to the area-reducing process (diameter-reducing and elongating process). Depending on the extent of these scratches or irregularities, gaps may form between the material and the sealing glass, for example, in lead pin applications, potentially impairing the sealing. Furthermore, it may be necessary to further improve the dimensional accuracy of the outer diameter of the material obtained in step (B). For this reason, the manufacturing method of the present invention may optionally include a step (D) in which the surface of the rod-shaped or wire-shaped material obtained in step (B) or the pin material obtained in step (C) is ground or polished, primarily for the purpose of eliminating scratches or irregularities on the material surface or improving dimensional accuracy. There are no particular restrictions on the method of grinding or polishing the material surface in this step (D), but since the material to be processed is a rod-shaped or wire-shaped material with a relatively small diameter, it is preferable to use centerless grinding and polishing.

[0053] <Airtight terminal and electric compressor of the present invention> The hermetic terminal of the present invention is a compression-sealed hermetic terminal equipped with the lead pin described above. Therefore, the lead pin is made of a [Cr and / or Mo]-Cu composite having a metal structure in which a Cr phase and / or Mo phase is dispersed in a Cu matrix. This [Cr and / or Mo]-Cu composite is a diameter-reduced and drawn powder metallurgy compact, and when observed through an optical microscope (for example, at 120x magnification), it is characterized by having an axial cross-sectional structure in which lamellar or linear Cr and / or Mo phases are dispersed in the Cu matrix, and a radial cross-sectional structure in which flake-like, small-platelet-like, or granular Cr and / or Mo phases are dispersed in the Cu matrix. The details of the lead pins provided in this airtight terminal are as explained above. The electric compressor of the present invention is an electric compressor equipped with the airtight terminal. Therefore, the airtight terminal of the present invention and the electric compressor of the present invention equipped with this airtight terminal can each enjoy the effects of the lead pin of the present invention described above.

[0054] <Study on the joint reliability of the lead pin of the present invention> Next, the results of an investigation based on material mechanics into the bonding reliability when the lead pin of the present invention is applied to a compression-sealed glass hermetic seal are shown below. Note that in the following explanation, the stem base is referred to as the "housing." Also, in the following explanation (including Tables 1 to 3), "%" regarding the material composition means "mass%." We investigated the application of the lead pin of the present invention to a compression-sealed glass hermetic seal provided in an airtight terminal. Specifically, we investigated the joint reliability of a compression-sealed glass hermetic seal consisting of a housing made of carbon steel S45C, sealing glass made of ST-4W (glass cord, manufactured by Nippon Electric Glass Co., Ltd.), and a lead pin made of the material of the present invention (55% Cr-Cu composite wire) using a simplified material mechanics approach in a concentric cylinder.

[0055] 5 and 6 are schematic diagrams of the compression-sealed glass hermetic seal used in this study (conceptual diagrams showing the dimensions and thermal expansion coefficients of the constituent parts, the compressive stress within the seal, etc.), with FIG. 5(A) being a schematic longitudinal cross-sectional view of the entire seal, FIG. 5(B) being a schematic plan view of the same, and FIG. 5(C) being a schematic plan view of the sealing glass. Also, FIG. 6(A) is a schematic longitudinal cross-sectional view of the entire seal, FIG. 6(B) is a schematic plan view of the housing and sealing glass, and FIG. 6(C) is a schematic plan view of the sealing glass and lead pin. The numerical values shown in FIGS. 5 and 6 are the average thermal expansion coefficients of the components that make up the seal. For ease of explanation, the metal material that makes up the lead pin of the present invention will be referred to as "55% Cr-Cu material" in the following description. Because the thermal expansion coefficient of the housing (carbon steel S45C) is greater than that of the sealing glass, the outer radial surface (outer periphery) of the sealing glass receives compressive stress P1 from the inner radial surface (inner periphery) of the housing while the sealing glass cools to room temperature after hardening.

[0056] The volume of the sealing glass is determined at approximately [glass transition point - 30°C] relative to the glass transition point where it completely hardens (the glass transition point of the above ST-4W: 460°C), and at 30°C it shrinks in volume due to the coefficient of thermal expansion. The calculated outer radius of the sealing glass R2' (radius at the outer surface of the sealing glass) is larger than the inner radius R2 (radius at the inner surface of the housing) due to housing shrinkage, but it matches the inner radius R2 of the housing due to the compressive stress P1 during sealing (see Toshiba Glass Technical Report 26, "On Glass Distortion"). The inner radius of the sealing glass (radius at the inner surface of the sealing glass) is displaced by υ2 toward the inner diameter (due to compressive strain caused by compressive stress P1) to become R3". The compressive stress P1 acting on the sealing glass from the housing can be predicted by calculating the displacement difference υ2 as a "thick-walled cylinder subjected to external pressure" in material mechanics.

[0057] The radial thermal expansion coefficient of the 55% Cr-Cu material that makes up the lead pin is greater than that of the sealing glass, so after the sealing glass hardens and cools to room temperature, the lead pin contracts more radially than the sealing glass, resulting in a calculated gap δ3 (the difference between the calculated inner radius of the sealing glass R3' and the calculated outer radius of the lead pin R3). If the displacement υ2 of the sealing glass toward the inner diameter is greater than this gap δ3, in other words, if R3" (= R3' - υ2) is smaller than R3, then no gap will occur at the interface between the sealing glass and the lead pin, and there is a possibility of achieving reliable bonding. In this case, the lead pin will be subjected to compressive stress P2 from the sealing glass due to the displacement difference υ3 between R3 and R3". In other words, the sealing glass will be subjected to compressive stress P1 on its outer radial surface from the housing, while the sealing glass will apply compressive stress P2 to the lead pin from its inner radial surface. This compressive stress P2 can be predicted by calculating the displacement difference υ3 as a "combined cylinder" in material mechanics.

[0058] The reliability of the bonding between the sealing glass and the housing and between the sealing glass and the lead pins is considered as follows. Because the difference in thermal expansion between the housing (carbon steel S45C) and the sealing glass is large in the thickness direction (height direction in the drawing, same below), shear stress occurs in the thickness direction at the interface between the housing and the sealing glass during sealing. However, because this combination is commonly used, it is unlikely that immediate interfacial delamination will occur. This is because compressive strain remains in the sealing glass during sealing. The shear stress at the glass interface in the thickness direction caused by this residual strain is on the compressive side, which is a characteristic of glass that is strong, and is also relieved by the radial compressive stress P1 (interfacial adhesion stress). When the temperature rises in the operating environment, the shear stress at the glass interface in the thickness direction becomes on the tensile side, which is a characteristic of glass that is weak. However, the residual compressive strain in the glass is thought to be able to relieve this tensile stress. However, under more severe operating conditions, there is a possibility that problems with joint reliability may arise. Furthermore, a commonly used combination of Kovar lead pins and FN-13W (glass cord, manufactured by Nippon Electric Glass Co., Ltd.) sealing glass is 2×10 times stronger than the sealing glass. -6 The difference in thermal expansion between the lead pin and the sealing glass causes undesirable tensile strain in the sealing glass. Therefore, in terms of material properties, this combination does not provide sufficient bonding reliability.

[0059] On the other hand, the bonding reliability on the inner radial surface of the sealing glass can be considered as follows. Calculation results show that the compressive stress P2 from the inner radial surface of the sealing glass to the outer radial surface of the lead pin tends to be smaller than the compressive stress P1 from the housing to the outer radial surface of the sealing glass. Therefore, if the axial thermal expansion coefficient of the lead pin is greater than that of the sealing glass, just like the housing, compressive strain will remain in the sealing glass in the thickness direction, just like the housing, but the bonding reliability will tend to be lower at the inner radial surface of the sealing glass than at the outer radial surface of the sealing glass. However, the 55% Cr-Cu material that makes up the lead pin has a smaller axial thermal expansion coefficient than carbon steel, and if the difference in thermal expansion with the sealing glass is small, it is thought that bonding reliability can be achieved by the interfacial adhesion stress (compressive stress P2) between the sealing glass and the lead pin.

[0060] Furthermore, it is necessary to consider the compressive shear stress τ acting on the sealing glass interface in the lead pin axial direction and the housing thickness direction, and the balance between this compressive shear stress τ and the compressive stresses P1 and P2 in the sealing glass radial direction. If the thermal expansion coefficient of the housing in the plate-face direction and the lead pin radial direction is greater than that of the sealing glass, the sealing glass will undergo compressive strain that is favorable for glass after cooling. However, repeated temperature increases and decreases will affect the sealing glass with compression and tension. The difference in the thermal expansion coefficients between the housing thickness direction, the lead pin axial direction, and the sealing glass may cause shear stress fatigue, which may reduce joint reliability. For this reason, it is preferable that the thermal expansion coefficients of the housing in the thickness direction, the lead pin axial direction, and the sealing glass be as close as possible to the compressive side of the sealing glass. Meanwhile, it is preferable that the compressive stresses P1 and P2 in the sealing glass radial direction are large. Therefore, the smaller the values of τ / P1 and τ / P2 are (although negative values are acceptable as long as they are sufficiently small), the higher the joint reliability between the lead pin and the housing and the sealing glass. In the case of lead pins, when comparing 55% Cr-Cu material with 50.5% Ni-Fe material, the compressive stress P2 of the 55% Cr-Cu material is about 91% of that of the 50.5% Ni-Fe material and about 88% of that of the copper-core pin, but the 55% Cr-Cu material, which has a smaller difference in the thermal expansion coefficient from the sealing glass in the axial direction, has a τ / P2 that is about 86% lower than that of the 50.5% Ni-Fe material and about 93% lower than that of the copper-core pin, resulting in higher joint reliability. Even though the 55%Cr-Cu material has the characteristic that the average axial thermal expansion coefficient from 30°C to 450°C is less than the average radial thermal expansion coefficient from 30°C to 450°C when used as a lead pin, it can obtain compressive stress from the sealing glass in the radial direction and also ensure joint reliability in the axial direction.

[0061] The calculation results for the above-mentioned displacement differences υ2, υ3 and compressive stresses P1, P2, the thickness direction shear stress τ1 from the housing to the sealing glass interface, the axial direction shear stress τ3 from the lead pin to the sealing glass interface, τ1 / P1 and τ3 / P2 are shown below. The physical properties of each material used in this calculation will be described later. In the calculations below, the values enclosed in brackets [ ] below specific values are those obtained when the lead pin is made of a conventional 50.5% Ni-Fe alloy (average axial thermal expansion coefficient (30-450°C): 10.3 x 10 -6 / K).

[0062] ●The dimensional changes of the housing (carbon steel), sealing glass, and lead pin (55% Cr-Cu material) from 430℃ to 30℃ are shown below. In Figures 5 and 6, when R1 = 8 mm, R2 = 3 mm, and R3 = 1.6 mm, the dimensions at temperatures of 430°C and 30°C are as follows. <At 430℃> · Housing inner radius = Sealing glass outer radius = R2*(1+α1*(430℃-30℃)) =3.018318mm · Sealing glass inner radius = lead pin outer radius = R3*(1+α3*(430℃-30℃)) =1.609219mm [1.607981mm] <At 30℃> Housing outer radius = 8mm = R1 ·Inner radius of housing = Outer radius of sealing glass = 3mm = R2 Calculated outer radius of sealing glass: R2' = 3.018318 * (1 - α2 * (430℃ - 30℃)) =3.006848mm → The sealing glass is compressed to 3 mm and is subjected to a compressive stress of υ2, the difference in displacement. Calculated inner radius of sealing glass: R3'=1.609219*(1-α3*(430℃-30℃)) =1.603104mm [1.6001870mm] Lead pin outer radius = 1.6 mm = R3 →δ3=1.603104-1.6=0.003104mm [0.001870mm]

[0063] The volume of the sealing glass is determined near the glass transition point - 30°C, and at 30°C it shrinks due to the thermal expansion coefficient. The calculated volume of the sealing glass and the volume after sealing are constant, but assuming that the thickness of the sealing glass does not change, At 30°C, the calculated surface area of the sealing glass is as follows: R2'=3.006848mm, R3'=1.603104mm → 20.33mm 2 The outer radius of the sealing glass is 3 mm. Inner radius of the sealing glass: R3" = 1.590222 mm (υ2 = 0.012882 mm). [1.588978mm] [0.012892mm] The compressive stress P1 from the housing due to the displacement υ2 on the inner diameter side of the sealing glass is calculated using the following formula.

number

[0064] ●The compressive stress P2 is as follows: If there are no lead pins, the inner radius of the sealing glass: R3" = R3'-υ2 =1.590222mm ·R3>R3”→ R3-R3”=υ3=0.00978mm [0.01102mm] → The lead pin receives compressive stress P2 from the sealing glass due to υ3. The compressive stress P2 from the sealing glass to the lead pin is calculated using the following formula.

number

[0065] ●The thickness direction compressive shear stress τ1 acting on the interface from the housing to the sealing glass and [thickness direction compressive shear stress τ1 acting on the interface from the housing to the sealing glass] / [radial compressive stress P1 from the housing to the sealing glass] are calculated as follows. In Figures 5 and 6, when R1 = 8 mm, R2 = 3 mm, R3 = 1.6 mm, and the housing thickness T1 = 6 mm, the dimensions at temperatures of 430°C and 30°C are as follows. <At 430℃> Carbon steel thickness = sealing glass thickness; T1' = 6 * (1 + α1 * (430℃ - 30℃)) =6.036636mm <At 30℃> Sealing glass thickness: T2' = T1' * (1 - α2 * (430℃ - 30℃)) = 6.013697 mm

[0066] → Compressive strain ε from the housing to the sealing glass after cooling = (T2'-T1) / T1 =0.002283 Compressive stress: Pt1 = glass elastic modulus * ε = 0.15523 GPa = 155.23 MPa [155.23MPa] Compression force: Ft1=Pt1*π*R2 2 =4389N [4389N] The compressive shear stress τ1 in the thickness direction acting from the housing to the sealing glass interface is given by: τ1=Ft1 / (π*2*R2*T1)=38.81MPa [38.81MPa] →Therefore, [compressive shear stress τ1 in the thickness direction acting on the interface from the housing to the sealing glass] / [compressive stress P1 in the radial direction from the housing to the sealing glass] is as follows: τ1 / P1=0.1960 [0.1955]

[0067] The axial compressive shear stress τ3 acting from the lead pin to the sealing glass interface and [axial compressive shear stress τ3 acting from the lead pin to the sealing glass interface] / [radial compressive stress P2 from the sealing glass to the lead pin] are calculated as follows: <At 30℃> Thickness of lead pin in contact with sealing glass: T3' = T1' * (1 - α3 (430℃ - 30℃)) =6.013455mm [6.01177mm] → Compressive strain ε from the sealing glass to the lead pin after cooling = (T2'-T3') / T3' =0.000040 Compressive stress: Pt3 = glass elastic modulus * ε = 0.002730 GPa = 2.730 MPa [21.85MPa] Compression force: Ft3 = Pt1 * π * R3 2 =21.96N [175.7N]

[0068] The axial compressive shear stress τ3 acting from the lead pin to the sealing glass interface is given by: τ3=Ft3 / (π*2*R3*T1)=0.363MPa [2.908MPa] Therefore, [axial compressive shear stress τ3 acting from the lead pin to the sealing glass interface] / [radial compressive stress P2 from the sealing glass to the lead pin] is as follows: τ3 / P2=0.0039 [0.0285]

[0069] The above calculations were performed for cases where the lead pin was made of the 55% Cr-Cu material of the present invention, the housing was made of carbon steel S45C, and the sealing glass was made of ST-4W (glass cord, manufactured by Nippon Electric Glass Co., Ltd.). However, similar calculations were also performed for cases where the lead pin, housing, and sealing glass were made of other materials. Specifically, the lead pins were made of the 45% Cr-Cu material of the present invention, the 60% Mo-Cu material, and the 35% Mo-Cu material, as well as the comparative materials 50.5% Ni-Fe, SUS430, copper core pin, and 29% Ni-17% Co-Fe. The calculation results are shown in Tables 1 to 3, along with the above-mentioned calculation results. In Tables 1 to 3, "equivalent to the invention" indicates cases where the lead pin was made of the material of the present invention, and "equivalent to the comparative example" indicates cases where the lead pin was made of a material other than the material of the present invention. In the "Reference Examples" in Tables 1 and 3, in which 35% Mo-Cu material (the material of the present invention) was used for the lead pin, the average radial thermal expansion coefficient of the lead pin was approximately 18.0 × 10 -6 This is stated to show that the lead pin can receive compressive stress from the sealing glass if the temperature is 1000 K or less.

[0070] The physical properties of the materials used in the calculations in Tables 1 to 3 are as follows: (1) Housing Carbon steel S45C Average thermal expansion coefficient α1 (20-500℃): 14.2×10 -6 / K Young's modulus E1: 205GPa Poisson's ratio ν1:0.25 SUS304 Average thermal expansion coefficient α1 (0-538℃): 18.8×10 -6 / K Young's modulus E1: 193GPa Poisson's ratio ν1:0.3 SUS430 Average thermal expansion coefficient α1 (0-538℃): 11.7×10 -6 / K Young's modulus E1: 200GPa Poisson's ratio ν1:0.27

[0071] (2) Lead pin ·55%Cr-Cu material (area reduction rate: 96.8%) Radial average thermal expansion coefficient α3 (30-450℃): 13.4×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 9.6×10 -6 / K Young's modulus E3: 206GPa Poisson's ratio ν3:0.25 ·45%Cr-Cu material (area reduction rate: 75.0%) Radial average thermal expansion coefficient α3 (30-450℃): 15.2×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 10.7×10 -6 / K Young's modulus E3: 198GPa Poisson's ratio ν3:0.26 ·60%Mo-Cu material (area reduction rate: 80.0%) Radial average thermal expansion coefficient α3 (30-450℃): 13.4×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 7.6×10 -6 / K Young's modulus E3: 242GPa Poisson's ratio ν3:0.33 ·35%Mo-Cu material (area reduction rate: 97.6%) Radial average thermal expansion coefficient α3 (30-450℃): 17.7×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 9.3×10 -6 / K Young's modulus E3: 188GPa Poisson's ratio ν3:0.33

[0072] 50.5% Ni-Fe material Radial average thermal expansion coefficient α3 (30-450℃): 11.6×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 10.3×10 -6 / K Young's modulus E3: 162GPa Poisson's ratio ν3:0.30 SUS430 Radial average thermal expansion coefficient α3 (30-450℃): 11.3×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 11.3×10 -6 / K Young's modulus E3: 200GPa Poisson's ratio ν3:0.27 Copper core pin Radial average thermal expansion coefficient α3 (30-450℃): 11.1×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 11.1×10 -6 / K Young's modulus E3: 157GPa Poisson's ratio ν3:0.31 29%Ni-17%Co-Fe material (Kovar) Radial average thermal expansion coefficient α3 (30-450℃): 5.3×10 -6 / K Average axial thermal expansion coefficient (30-450℃): 5.3×10 -6 / K Young's modulus E3: 152GPa Poisson's ratio ν3:0.3

[0073] (3) Sealing glass ST-4W (glass cord, manufactured by Nippon Electric Glass Co., Ltd.) Average thermal expansion coefficient α2 (30-380℃): 9.5×10 -6 / K Glass transition temperature Tg: 460℃ Young's modulus E2: 68GPa Poisson's ratio ν2:0.21 FN-13W (glass cord, manufactured by Nippon Electric Glass Co., Ltd.) Average thermal expansion coefficient α2 (30-380℃): 7.6×10 -6 / K Glass transition temperature Tg: 510℃ Young's modulus E2: 57GPa Poisson's ratio ν2:0.22 SG354 (glass cord, manufactured by AGC) Average thermal expansion coefficient α2 (50-350℃): 10.7×10 -6 / K Glass transition temperature Tg: 567℃ Young's modulus E2: 68GPa Poisson's ratio ν2:0.21

[0074] [Table 1]

[0075] [Table 2]

[0076] [Table 3]

[0077] From the calculation results in Tables 1 to 3, it can be determined that when the material of the present invention is used for the lead pin (corresponding to the invention example), a compressive pressure P2 from the sealing glass to the lead pin is obtained, and τ3 / P2 is sufficiently low, so that the required bonding reliability is obtained. In particular, as shown in Tables 2 and 3, by roughly matching the average axial thermal expansion coefficient of the lead pin to the average thermal expansion coefficient of the sealing glass, the shear stress generated between the lead pin and the sealing glass can be reduced to almost zero, making it possible to maximize bonding reliability. On the other hand, the comparative example in Table 3 is a commonly used combination of Kovar lead pins and FN-13W sealing glass (glass cord, manufactured by Nippon Electric Glass Co., Ltd.). As mentioned above, the lead pins are 2 x 10 times thinner than the sealing glass. -6 / K, the value of τ3 / P2 is minus 0.44, which means tensile strain that is undesirable for sealing glass, and it can be seen that the numerical results show that the bonding reliability is not sufficient. [Example]

[0078] Lead pins of the present invention (rod- or wire-shaped metal material constituting a lead pin; hereinafter referred to as "material of the present invention") were manufactured under the manufacturing conditions shown below, and their properties were measured. Furthermore, as comparative materials, a material made of a [Cr and / or Mo]-Cu composite (area reduction rate: 0%) that had not been subjected to area reduction (diameter-reducing and elongation processing), a pure Cu material, a 50.5% Ni-Fe material, and a copper-core pin (50% Ni-Fe with copper clad in the center) were used as test materials, and their properties were measured in the same manner as above. The results are shown in Tables 4 and 5, along with the configuration (composition, density) and manufacturing conditions (area reduction rate) of the metal material. In the description of this example (including Tables 4 and 5), "%" regarding the composition of the material means "mass%." Although not shown in Tables 4 and 5, the materials of the present invention have a cross-sectional structure as shown in Fig. 1, i.e., when observed with an optical microscope, they have a cross-sectional structure in the stretching direction (axial direction) in which lamellar or linear Cr and / or Mo phases are dispersed in a Cu matrix, and a cross-sectional structure in the transverse direction (radial direction) in which flake-like, small-sized, or granular Cr and / or Mo phases are dispersed in a Cu matrix. In contrast, a comparative material made of a [Cr and / or Mo]-Cu composite that has not been subjected to area reduction (diameter-reducing elongation) (area reduction rate: 0%) naturally does not have such a characteristic cross-sectional structure, but rather has a cross-sectional structure similar to the "infiltrant cross section" in Fig. 2.

[0079] (1) Production of materials for surface reduction processing Cr and / or Mo powders were placed in a mold and pressed, or a mixture of Cr and / or Mo powders and Cu powders in a specified ratio was placed in a mold and pressed to form a compact. A pure Cu plate was placed on top of this compact, and sintering and Cu infiltration were performed in a reducing atmosphere. Specifically, the compact was first sintered (1000°C, 600 minutes) to form a sintered compact. The temperature was then raised to melt the pure Cu plate, and the Cu was impregnated into the sintered compact through Cu infiltration (1200°C, 180 minutes). A milling machine was used to remove the remaining Cu from the surface of the [Cr and / or Mo]-Cu composite, and the shape was adjusted to obtain a rod-shaped blank of the specified size for surface reduction processing.

[0080] (2) Manufacturing of the material of the present invention by area reduction processing (diameter reduction and elongation processing) (2.1) Examples 1 to 29, 36 to 47 The material for area reduction, which had been milled to a hexagonal cross-section prism shape (thickness 20.7 mm), was then swaged and subsequently combined roll rolled to reduce the area to φ3.7 mm (diameter reduction and elongation), and further reduced the area (diameter reduction and elongation) by a finishing drawing process consisting of a two-stage roller die drawing (CRD) to obtain the material of the present invention with an outer diameter of φ3.2 mm. (2.2) Examples 32 to 35 The material for area reduction, which had been milled to an octagonal cross-section prism shape (thickness 50 mm), was reduced in area (diameter reduction and elongation) to an outer diameter of φ15 mm by grooved roll rolling and subsequent swaging, and then reduced in area (diameter reduction and elongation) to a prism shape (octagonal cross-section) with a thickness of 3.7 mm by combined roll rolling.Furthermore, a finishing drawing process consisting of roller die drawing (CRD) and simple drawing (cold wire drawing using a wet method) was performed to reduce in area (diameter reduction and elongation), resulting in the material of the present invention with an outer diameter of φ3.2 mm.

[0081] (3) Measurement of characteristics For each test material, the axial and radial thermal expansion coefficients, and the axial electrical conductivity (and volume resistivity) were determined using the measurement and calculation methods described above. The axial electrical conductivity (and volume resistivity) was measured using an Advance Riko Electrical Resistivity Measuring Device TER-2000RH Special Model. In addition, for samples with the same material composition but different area reduction rates, material for the other samples was collected during the area reduction process of the sample with the largest area reduction rate, and this was processed into a φ3.2 mm sample by centerless grinding and used for each measurement.

[0082] According to Tables 4 and 5, the material of the present invention has a certain level of radial thermal expansion coefficient, while the axial thermal expansion coefficient is considerably smaller than the radial thermal expansion coefficient, and is comparable to the sealing glass of a compression-sealed glass hermetic seal (usually 8 to 11 × 10 -6It can be seen that the thermal expansion coefficient can be made close to that of the sealing glass (approximately / K). For example, as can be seen from examples such as "Nos. 5, 10, 15, 20," "Nos. 24, 29," "Nos. 37, 39," "Nos. 7 to 12," and "Nos. 26 to 29," the magnitude of the axial (extension direction) thermal expansion coefficient of the inventive material can be adjusted by selecting the Cr and / or Mo content and the area reduction rate during diameter reduction and elongation. Therefore, the axial (extension direction) thermal expansion coefficient can be made as close as possible to the thermal expansion coefficient of the sealing glass. Furthermore, it can be seen that the inventive material has significantly higher axial electrical conductivity than the comparative materials (conventional lead pins) such as 50.5% Ni-Fe and copper-core pins. Furthermore, as can be seen from examples such as "Nos. 7 to 12" and "Nos. 26 to 29" of the present invention, the axial electrical conductivity of the material of the present invention can be changed not only by changing the component composition but also by changing the area reduction rate during diameter reduction and elongation, so that the axial electrical conductivity can be adjusted according to the application equipment, etc. From the above, it can be seen that the lead pin of the compression-sealing type glass hermetic seal of the present invention has high bonding reliability with the sealing glass, and despite its small diameter, generates little heat when a large current is passed through it.

[0083] [Table 4]

[0084] [Table 5] [Explanation of symbols]

[0085] 1 stem base 2 lead pins 3 Sealing glass 4 Insertion hole

Claims

1. A lead pin that constitutes a compression-sealed glass hermetic seal, The composite is a [Cr and / or Mo]-Cu composite having a metal structure in which a Cr phase and / or Mo phase are dispersed in a Cu matrix, The [Cr and / or Mo]-Cu composite is a diameter-reduced and drawn material of a powder metallurgy compact, and when cross-sectionally observed with an optical microscope, has an axial cross-sectional structure in which lamellar or linear Cr phases and / or Mo phases are dispersed in a Cu matrix, and a radial cross-sectional structure in which flake-like, small-piece-like, or granular Cr phases and / or Mo phases are dispersed in a Cu matrix, which is a lead pin for a compression-sealed glass hermetic seal.

2. Average axial thermal expansion coefficient from 30°C to 450°C is 7.0 to 12.0 x 10 －６ / K, and the average radial thermal expansion coefficient from 30°C to 450°C is 18.0 × 10 －６ 2. The lead pin of a compression-sealed glass hermetic seal according to claim 1, wherein the average axial thermal expansion coefficient from 30°C to 450°C is less than or equal to 1 / K, and the average radial thermal expansion coefficient from 30°C to 450°C is less than or equal to 1 / K.

3. Axial electrical conductivity is 20.0 x 10 ６ 3. The lead pin of a compression-sealing type glass hermetic seal according to claim 1, wherein the resistance is 500 kJ / m or more.

4. 2. The lead pin of a compression-sealed glass hermetic seal according to claim 1, wherein the [Cr and / or Mo]-Cu composite has a total Cr and / or Mo content of 35 to 60 mass%.

5. 2. The lead pin for a compression-sealed glass hermetic seal according to claim 1, wherein the surface of the pin body made of the [Cr and / or Mo]--Cu composite has a surface treatment film.

6. A method for manufacturing the lead pin according to claim 1, comprising the steps of: A step (A) of obtaining a material for surface reduction processing comprising a [Cr and / or Mo]-Cu composite through a step of sintering a powder raw material; A step (B) of reducing the area of the material obtained in the step (A) and drawing it into a rod or wire shape by reducing the diameter; The method for manufacturing a lead pin comprises a step (C) of cutting the rod-shaped or wire-shaped material obtained in the step (B) to a predetermined length to obtain a pin material.

7. 7. The method for manufacturing a lead pin according to claim 6, wherein the step (B) includes a step of subjecting the material to a finish drawing process.

8. 7. The method for manufacturing a lead pin according to claim 6, further comprising a step (D) of grinding or polishing the surface of the rod-shaped or wire-shaped material obtained in step (B) or the pin material obtained in step (C).

9. 8. The method for manufacturing a lead pin according to claim 6, further comprising the step of subjecting the pin material that has been subjected to step (C) to a surface treatment.

10. A method for manufacturing a lead pin as described in claim 8, further characterized in that a surface treatment is applied to a pin material that has undergone steps (C) and (D) in that order, or to a pin material that has undergone steps (D) and (C) in that order.

11. In compression-sealed hermetic terminals, the lead pin is made of a [Cr and / or Mo]-Cu composite having a metal structure in which a Cr phase and / or Mo phase is dispersed in a Cu matrix; The [Cr and / or Mo]-Cu composite is a diameter-reduced and stretched material of a powder metallurgy compact, and when cross-sectionally observed with an optical microscope, has an axial cross-sectional structure in which lamellar or linear Cr phases and / or Mo phases are dispersed in a Cu matrix, and a radial cross-sectional structure in which flake-like, small-piece-like, or granular Cr phases and / or Mo phases are dispersed in a Cu matrix.

12. The lead pin has an axial average thermal expansion coefficient of 7.0 to 12.0×10 from 30° C. to 450° C. －６ / K, and the average radial thermal expansion coefficient from 30°C to 450°C is 18.0 × 10 －６ / K or less, and the average axial thermal expansion coefficient from 30°C to 450°C is less than the average radial thermal expansion coefficient from 30°C to 450°C.

13. The lead pin has an axial electrical conductivity of 20.0×10 ６ 13. The hermetic terminal according to claim 11, wherein the strength is S / m or more.

14. 12. The hermetic terminal according to claim 11, wherein the [Cr and / or Mo]--Cu composite has a total content of Cr and / or Mo of 35 to 60 mass %.

15. 12. The airtight terminal according to claim 11, wherein the lead pin has a surface treatment film on the surface of the pin body made of the [Cr and / or Mo]--Cu composite.

16. An electric compressor comprising the airtight terminal according to claim 11 or 12.

17. An electric compressor comprising the airtight terminal according to claim 13.

18. An electric compressor comprising the airtight terminal according to claim 15.

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