Vacuum valve, contact material for vacuum valve, and method for producing contact material for vacuum valve

Abstract

To easily obtain a contact material for a vacuum valve having desired properties.SOLUTION: A contact material for a vacuum valve according to an embodiment comprises copper and at least one arc-resistant component selected from chromium, molybdenum, tantalum and tungsten. The arc-resistant component has a three-dimensional structure, and at least a portion of the copper is provided within the three-dimensional structure.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a vacuum valve, a contact material for a vacuum valve, and a method for manufacturing a contact material for a vacuum valve.

Background Art

[0002] Due to the increasing need for higher capacity in air circuit breakers, improvement in the performance of vacuum valves is required. A vacuum valve has a structure in which both ends of a cylindrical insulating container made of an insulating material are sealed with metal flanges, and the inside of the insulating container is maintained at a high vacuum. Also, a pair of electrodes integrated with the flanges via bellows are connected to the operating mechanism of the circuit breaker and move in the axial direction of the vacuum valve. When an accident current occurs, the accident current can be interrupted by opening the electrodes.

[0003] A copper-chromium (Cu-Cr) based alloy is used as the electrode material for vacuum valves. There are three types of Cu-Cr based alloys with different manufacturing methods, for example, a melting material, a sintered material, and an impregnated material. The melting material is manufactured by melting the material in a vacuum atmosphere, then casting and rapidly cooling it. The Cr phase in the material is formed in a dendrite (branch) shape, and its size is generally as fine as 10 to 20 μm. There is almost no anisotropy in the distribution of the Cr phase. Also, due to the degassing effect in vacuum and rapid cooling by the mold, it is characterized by having a metal structure with little residual oxygen and fine and uniform dispersion of about 10 μm of Cr in the Cu matrix. Since it is rapidly cooled in the final process and there is a limit to the weight that can be melted at one time to maintain the cooling rate above a certain level, it is generally expensive but has the best electrical performance.

[0004] The sintered material is produced by sintering a green compact obtained by mixing and molding raw material powders in a vacuum or a reducing / inert atmosphere. The Cr phase is uniformly dispersed in a particulate form. The size of the Cr phase varies depending on the raw materials used, but generally ranges from 50 μm to 100 μm. In the sintering process of the Cu-Cr alloy, it is thermodynamically impossible to reduce oxidized Cr using a vacuum or a reducing / inert atmosphere. As a result, a large amount of oxygen remains in the sintered material, particularly deteriorating the current interruption capacity. Also, when the sintering density is low, the brazing components melted during production tend to penetrate into the internal pores, easily causing manufacturing defects. However, since a large number of green compacts can be sintered at once, the price is low.

[0005] The infiltrated material is produced by first fabricating a low-density sintered body of Cr and then infiltrating molten Cu into the low-density sintered body. Since the Cr phases in the material are in contact with each other to form a skeleton, dense and sparse portions of the Cr phase occur. By the effect of discharging the oxidized Cr layer on the surface of the Cr sintered body due to the flow of molten Cu, the residual oxygen amount can be reduced to the same level as that of the dissolved material. However, since the low-density sintered body of Cr has a minimum density at which its structure can be maintained, it is impossible to produce a Cu-Cr alloy with a Cr content of generally 40 wt% or less. Also, since Cu containing a large amount of impurities such as oxygen is discharged, the raw material utilization efficiency is poor and the price is high.

[0006] Although there are differences in the fine Cr phase distribution in each manufacturing method, they are common in that the Cr phase distribution can hardly be controlled. For example, in the vacuum melting method, the cooling rate of the molten metal is almost the only control parameter for the Cr phase distribution.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] Easily obtain a contact material for a vacuum valve having desired characteristics.

Means for Solving the Problem

[0009] According to an embodiment, there is provided a contact material for a vacuum valve including copper and at least one arc-resistant component among chromium, molybdenum, tantalum, or tungsten, wherein the arc-resistant component has a three-dimensional structure, and at least a part of the copper is provided within the three-dimensional structure.

Brief Description of the Drawings

[0010]

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Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described with reference to the drawings. Note that the disclosure is merely an example, and for those skilled in the art, appropriate modifications that maintain the gist of the invention and can be easily conceived are naturally included in the scope of the present invention. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present invention. Further, in this specification and each drawing, the same reference numerals may be assigned to the same elements as those described above with respect to the previously shown drawings, and detailed descriptions may be appropriately omitted.

[0012] According to the embodiment, a contact material for a vacuum valve according to the first embodiment, a vacuum valve according to the second embodiment, and a method for manufacturing a contact material for a vacuum valve according to the third embodiment are provided. In the embodiment, a material including a first component having a three-dimensional structure and a second component having a composition different from that of the first component and at least a part of which is provided within the three-dimensional structure can be used.

[0013] The material can include one or more three-dimensional structures. The three-dimensional structure can be formed, for example, by a metal additive manufacturing method. Examples of three-dimensional structures include a lattice structure, a columnar structure, or a porous structure. The three-dimensional structure of the arc-resistant component can be composed of a single element of Cr, Mo, Ta, or W, a solid solution thereof, an intermetallic compound, or a duplex alloy. According to the contact material for a vacuum valve according to the first embodiment, copper is used as the first component, and at least one arc-resistant component selected from copper (Cu) and chromium (Cr), molybdenum (Mo), tantalum (Ta), or tungsten (W) can be used as the second component. The arc-resistant component has a three-dimensional structure. At least a part of the Cu is provided within the three-dimensional structure.

[0014] According to the first embodiment, a contact material for a vacuum valve having characteristics corresponding to the shape of the arc-resistant component having a three-dimensional structure can be obtained. Thereby, without changing the composition of the material, by selecting the shape of the arc-resistant component having a three-dimensional structure, various characteristics such as mechanical characteristics, electrical characteristics, and thermal characteristics of the contact material for a vacuum valve can be adjusted.

[0015] FIG. 1 shows a model diagram representing a part of the cross-sectional structure of an example of the contact material for a vacuum valve according to the first embodiment. In FIG. 1, the three-dimensional structure is a lattice structure portion 103 having a lattice structure. As shown in the drawing, the contact material 101 for a vacuum valve includes an arc-resistant component having a lattice structure portion 103 such as Cr, for example, and a Cu matrix 104 at least a part of which is provided within a three-dimensional structure, for example, the lattice structure portion 103. Also, FIG. 2 shows a model diagram for explaining the lattice structure used in FIG. 1. Furthermore, FIG. 3 shows an enlarged view of the unit A of the three-dimensional structure of FIG. 2.

[0016] As shown in the figure, the lattice structure part 103 is provided here between the first base part 2 and the second base part 4. When applying the lattice structure part to the contact material 101 for the vacuum valve, the first base part 2 and the second base part 4 can be removed as necessary. If not removed, they can be used as integrated electrodes by processing them into a predetermined shape. As shown in FIGS. 2 and 3, the lattice structure part 103 has a three-dimensional lattice structure in which unit cells are spatially continuous.

[0017] The lattice structure part 103 has an element 103a1 (corresponding to an example of the first element) and an element 103b1 (corresponding to an example of the second element) on the first virtual plane 100a. The elements 103a1 and 103b1 exhibit a columnar shape such as a cylindrical shape, and are provided so as to be inclined to intersect each other. Also, the forms of the elements 103a1 and 103b1 may be columnar with a constant cross-sectional area, or may be columnar with a changing cross-sectional area. Note that the forms of the elements 103a1 and 103b1 are not limited to columnar shapes, and can be appropriately changed according to the use of the three-dimensional structural component 1 and the like. Also, the elements 103a1 and 103b1 are provided so that the positions where they intersect each other are integrated.

[0018] The cross-sectional dimensions, lengths, angle θa, and angle θb of the elements 103a1 and 103b1 can be appropriately changed according to the use of the three-dimensional structural component 1 and the like. Also, the lattice structure part 103 also has an element 103a2 (corresponding to an example of the third element) and an element 103b2 (corresponding to an example of the fourth element) on the second virtual plane 110a. For example, the second virtual plane 110a can be a plane orthogonal to the first virtual plane 100a. This can be done.

[0019] One end of the element 103a2 provided on the second virtual surface 110a intersects with one end of the element 103b1 provided on the first virtual surface 100a. Also, one end of the element 103a2 provided on the second virtual surface 110a intersects with one end of the element 103b3 provided on the third virtual surface 100b described later. Also, one end of the element 103b2 provided on the second virtual surface 110a intersects with one end of the element 103a1 provided on the first virtual surface 100a. Also, one end of the element 103b2 provided on the second virtual surface 110a intersects with one end of the element 103a3 provided on the third virtual surface 100b described later.

[0020] Note that the elements 103a2 and 103b2 illustrated in FIGS. 2 and 3 have the same form as the elements 103a1 and 103b1 described above. Also, the lattice structure portion 103 also has an element 103a3 (corresponding to an example of the fifth element) and an element 103b3 (corresponding to an example of the sixth element) on the third virtual surface 100b. For example, the third virtual surface 100b can be a surface parallel to the first virtual surface 100a and orthogonal to the second virtual surface 110a. One end of the element 103a3 provided on the third virtual surface 100b intersects with one end of the element 103b4 (corresponding to an example of the eighth element) provided on the fourth virtual surface 110b described later.

[0021] Also, one end of the element 103b3 provided on the third virtual surface 100b intersects with one end of the element 103a4 (corresponding to an example of the seventh element) provided on the fourth virtual surface 110b described later. The lattice structure referred to here is a structure in which unit cells are spatially continuous, and the columns (ribs) constituting the unit cells themselves can bear structural loads.

[0022] Figures 4 to 12 show model diagrams for explaining the unit cells used in the embodiments. As the unit cell, a lattice structure including the coordination structures shown in FIGS. 4 to 7, a parallelepiped lattice in FIGS. 8 to 12, or a combination thereof can be used. FIG. 4 represents a coordination structure of 4 - coordination, FIG. 5 represents a coordination structure of 6 - coordination, FIG. 6 represents a coordination structure of 8 - coordination, and FIG. 7 represents a coordination structure of 12 - coordination. Also, FIG. 8 represents a parallelepiped, FIG. 9 represents a regular hexagonal prism, FIG. 10 represents a rhombic dodecahedron, FIG. 11 represents an elongated rhombic dodecahedron, and FIG. 12 represents a truncated octahedron parallelepiped lattice.

[0023] The structures shown in FIGS. 2 and 3 are examples including an 8 - coordination structure. For example, A can be used as the unit cell. Conventionally, the current - conducting component and the arc - resistant component mainly composed of Cu could only be adjusted by weight ratio. However, when using a lattice structure in a three - dimensional structure, the spatial distribution of the current - conducting component and the arc - resistant component can be adjusted, so that the current - conducting characteristics, breaking characteristics, welding characteristics, heat - transfer characteristics, dielectric breakdown characteristics, and mechanical characteristics of the contact material for vacuum valves can be adjusted. When the number of coordinations of the coordination structure increases, the welding characteristics, heat - transfer characteristics, and current - conducting characteristics tend to decrease, while the breaking characteristics and dielectric breakdown characteristics tend to improve. Also, when the number of faces of the parallelepiped lattice structure increases, various characteristics such as the welding characteristics, heat - transfer characteristics, and current - conducting characteristics tend to decrease, while the breaking characteristics and dielectric breakdown characteristics tend to improve.

[0024] The diameters of the respective ribs 201, 202, 203, 204, 205, 206, 207, 208, and 209 constituting the unit cell can be set to 0.2 to 1 mm, for example, as shown by the diameter d1 of the rib 201 in FIG. 4. The unit cell size is represented by W1 in FIG. 8, for example. This unit cell size can be determined such that the weight ratio of Cu to the arc-resistant component is 1:0.1 to 1:2. When the arc-resistant component is Cr, the unit cell size can be determined such that the weight ratio of Cu to Cr is 1:0.34. If the rib diameter d1 is less than 0.2 mm, the structure cannot be maintained in the manufacturing process and tends to deform significantly. If it exceeds 1 mm, the interruption characteristics and the withstand voltage insulation characteristics tend to deteriorate. Also, if the weight ratio of the arc-resistant component to Cu is less than 0.1, the withstand voltage insulation characteristics tend to deteriorate. If it exceeds 2, the interruption characteristics tend to deteriorate.

[0025] FIGS. 13 to 15 show model diagrams for explaining a columnar structure as another three-dimensional structure of the arc-resistant component. As shown in FIG. 13, the columnar structure 301 of the arc-resistant component has, for example, a plate-shaped first base 301b and a plurality of cylinders 301a provided in one direction, for example, the vertical direction, on one surface 301b-1 of the first base 301b. The plurality of cylinders 301a have a column diameter d2 and are arranged at intervals of a pitch p1. The first base 301b can be removed when processing the contact material for the vacuum valve to create a contact. When using the columnar structure 301 as the contact material for the vacuum valve, the columnar structure 301 of the arc-resistant component in FIG. 13 can be machined into a desired shape.

[0026] FIG. 14 shows a model diagram representing another example of the contact material for the vacuum valve according to the first embodiment. The contact material for the vacuum valve shows a model diagram representing an example of the contact material for the vacuum valve using the columnar structure of FIG. 13. As shown in the figure, the contact material 304-1 for vacuum valves has a disc shape and includes an arc-resistant component having a columnar structure 301 that includes a plurality of columns 301a made of, for example, Cr, and a Cu matrix 305 provided at least partially within the columnar structure 301. One surface 304-1a of the contact material 304-1 for vacuum valves can be used as a functional surface. The plurality of columns 301a are provided perpendicular to the functional surface 304-1a. The functional surface refers to a surface that functions as a contact between a pair of electrodes of a vacuum valve. The functional surface of the contact used for one electrode is the surface facing the other electrode.

[0027] When using a columnar structure, anisotropy can be added to the current path and heat transfer path, so that the heat transfer characteristics and energization characteristics of the contact material for vacuum valves can be adjusted. Also, when the direction of the columns of the columnar structure is perpendicular to the functional surface, the heat transfer characteristics and energization characteristics can be adjusted to be improved. The column diameter d2 can be set to 0.2 to 1 mm. The pitch p1 between columns can be set such that the weight ratio of the arc-resistant component to Cu is 1:0.1 to 2. Furthermore, when the arc-resistant component is Cr, the weight ratio of Cu:Cr can be set to 1:0.34. If the column diameter d2 is less than 0.2 mm, the structure tends to be deformed and cannot be maintained in the manufacturing process. If it exceeds 1 mm, the interruption characteristics and dielectric withstand voltage characteristics tend to decrease. Also, if the weight ratio of the arc-resistant component to Cu is less than 0.1, the dielectric withstand voltage characteristics tend to decrease, and if it exceeds 2, the interruption characteristics tend to decrease.

[0028] FIG. 15 shows a model diagram representing another example of the contact material for vacuum valves according to the first embodiment. The contact material for vacuum valves shows a model diagram representing another example of the contact material for vacuum valves using the columnar structure of FIG. 13. As shown in the figure, the contact material 304-2 for vacuum valves is disc-shaped and includes an arc-resistant component having a columnar structure 301 containing a plurality of columns 301a made of, for example, Cr, and a Cu matrix 305 provided at least partially within the columnar structure 301. One surface 304-2a of the contact material 304-2 for vacuum valves can be used as a functional surface. The plurality of columns 302a are provided parallel to the functional surface 304-2a.

[0029] When the direction of the columns in the columnar structure is made parallel to the functional surface facing the other electrode, it can be adjusted to improve the welding characteristics of the contact material for vacuum valves. The column diameter d2 can be 0.2 to 1 mm. The pitch p1 between columns can be set such that the weight ratio of Cu to the arc-resistant component is 1:0.1 to 2, and further, when the arc-resistant component is Cr, the weight ratio of Cu to Cr is 1:0.34. If the column diameter d2 is less than 0.2 mm, the structure cannot be maintained in the manufacturing process and tends to deform greatly. If it exceeds 1 mm, the current-carrying characteristics, heat transfer characteristics, dielectric withstand voltage characteristics, and interruption characteristics tend to decrease significantly. Also, if the weight ratio of the arc-resistant component to Cu is less than 0.1, the dielectric breakdown characteristics tend to decrease, and if it exceeds 2, the interruption characteristics tend to decrease.

[0030] Furthermore, when using a porous structure as another three-dimensional structure of the arc-resistant component, by forming a fine and strong three-dimensional network of the arc-resistant component, the dielectric breakdown and interruption characteristics of the contact material for vacuum valves can be adjusted. The porosity of the porous structure can be 10 to 60%. If the porosity is less than 10%, the pores tend to close and the Cu matrix cannot penetrate (immerse) into the three-dimensional structure of the arc-resistant component. If it exceeds 60%, the structure cannot be maintained in the manufacturing process and tends to deform greatly. The size (particle size) of the arc-resistant component of the minimum unit constituting the three-dimensional network of the arc-resistant component is 10 μm to 50 μm. If it is less than 10 μm, the structure cannot be maintained in the manufacturing process and tends to deform greatly. If it is 50 μm or more, the dielectric breakdown characteristics and interruption characteristics decrease.

[0031] The vacuum valve according to the second embodiment includes an electrode including a contact made of the contact material for a vacuum valve according to the first embodiment. According to the second embodiment, by using the contact material for a vacuum valve according to the first embodiment as the contact, a vacuum valve having a contact having characteristics corresponding to the shape of the arc-resistant component having a three-dimensional structure can be obtained. Further, various characteristics of the contact material for a vacuum valve can be adjusted by selecting the shape of the arc-resistant component having a three-dimensional structure without changing the composition of the contact material for a vacuum valve.

[0032] FIG. 16 shows a longitudinal sectional view showing the configuration of the vacuum valve according to the second embodiment. As shown in the drawing, the vacuum valve 100 has openings at both ends, and includes a cylindrical ceramic container 1 made of, for example, alumina porcelain, a fixed-side sealing fitting 2 sealed to one opening, and a movable-side sealing fitting 3 sealed to the other opening. A vacuum is maintained inside the vacuum valve 100. The fixed-side sealing fitting 2 is provided with a central opening, and a fixed-side current-carrying shaft 4 serving as one electric path penetrates and is fixed. A fixed-side electrode 5 is fixed to the end of the fixed-side current-carrying shaft 4 inside the ceramic container 1. By fixing a fixed-side contact 6 to the end face of the fixed-side electrode 5, a joining structure of the fixed-side electrode 5 and the fixed-side contact 6 is formed. A movable-side contact 7 that faces the fixed-side contact 6 and serves as a pair of separable contacts is fixed to the end face of the movable-side electrode 8, thereby forming a joining structure of the fixed-side contact 6 and the movable-side contact 7. The movable-side electrode 8 is fixed to the end of a movable-side current-carrying shaft 9 serving as another electric path that movably penetrates a central opening provided in the movable-side sealing fitting 3.

[0033] Here, the contact material for a vacuum valve according to the first embodiment can be used as the contact for the fixed-side contact 6 and the movable-side contact 7. The functional surface 6a of the fixed-side contact 6 provided on the end face of the fixed-side electrode 5 faces the functional surface 7a of the movable-side electrode 8 and the movable-side contact 7 provided on its end face. On the other hand, the functional surface 7a of the movable-side contact 7 provided on the end face of the movable-side electrode 8 faces the functional surface 6a of the fixed-side electrode 5 and the fixed-side contact 6 provided on its end face.

[0034] A portion of the movable-side energizing shaft 9 from its central portion to the side of the movable-side sealing fitting 3 is a portion led out of the ceramic container 1, and a bellows cover 10 for airtight sealing is provided at that portion. One end of a telescopic cylindrical bellows 11 is disposed on the bellows cover 10. The other end of the bellows 11 is sealed to the central opening of the movable-side sealing fitting 3. Thereby, the vacuum of the insulating container 1 can be maintained and the movable-side energizing shaft 9 can be moved in the axial direction. Around the fixed-side electrode 5, the movable-side electrode 8, the fixed-side contact 6, and the movable-side contact 7, a cylindrical arc shield 12 is provided to prevent metal vapor and molten metal generated during opening and closing from adhering to the inner wall of the insulating container 1 and reducing the insulation resistance.

[0035] The method for manufacturing a contact material for a vacuum valve according to the third embodiment includes forming a three-dimensional structure of at least one arc-resistant component among Cr, Mo, Ta, or W, and infiltrating molten Cu into the interior of the three-dimensional structure of the arc-resistant component. According to the third embodiment, a contact material for a vacuum valve having characteristics corresponding to the shape of the arc-resistant component having a three-dimensional structure can be obtained. Thereby, without changing the composition of the material, various characteristics of the contact material for a vacuum valve can be adjusted by selecting the shape of the arc-resistant component having a three-dimensional structure.

[0036] FIG. 17 shows a flowchart showing the method for manufacturing a contact material for a vacuum valve according to the third embodiment. As shown in the figure, in the method for manufacturing a contact material for a vacuum valve according to the third embodiment, first, a three-dimensional structure of at least one arc-resistant component among Cr, Mo, Ta, or W is formed (ST1), and molten copper is infiltrated into the interior of the three-dimensional structure of the arc-resistant component (ST2), whereby a contact material for a vacuum valve in which at least a part of Cu is provided in the three-dimensional structure can be obtained. According to the embodiment, a contact material for a vacuum valve having characteristics corresponding to the shape of the arc-resistant component having a three-dimensional structure can be obtained. Thereby, without changing the composition of the material, a contact material for a vacuum valve having desired characteristics can be easily obtained by selecting the shape of the arc-resistant component having a three-dimensional structure. The three-dimensional structure can be formed, for example, by a metal additive manufacturing method. The metal additive manufacturing method is a technology for manufacturing products using a 3D printer according to the metal material. Examples of the metal additive manufacturing method include a powder bed fusion method (powder bed method) using a laser heat source and an electron beam heat source, or a directed energy deposition method (metal deposition method) using a laser heat source.

[0037] As a method for infiltrating molten Cu into the three-dimensional structure, for example, melting Cu and adding and infiltrating the molten Cu into the three-dimensional structure (infiltration), or adding Cu to the three-dimensional structure and heating them together to infiltrate the molten Cu into the three-dimensional structure can be mentioned. The melting points of Cr, Mo, Ta, and W used as arc-resistant components are higher than that of Cu. The heating temperature can be set to a temperature equal to or higher than the melting point of Cu and lower than the melting point of the arc-resistant component. For example, in the case of Cu, it can be set to 1100 - 1300 °C.

[0038] Hereinafter, examples will be shown to specifically describe the embodiments. Examples Comparative Example 1 (Example of general-purpose material ingot) A Cu75 wt%-Cr25 wt% ingot manufactured by a melting method as a general-purpose contact material for vacuum valves was processed into a disc shape by cutting, and was applied to the fixed-side contact 6 of the fixed-side electrode 5 of oxygen-free copper and the movable-side contact 7 of the movable-side electrode 8 of oxygen-free copper, respectively, in the same manner as the vacuum valve shown in Fig. 16. The fixed-side electrode 5, the movable-side electrode 8, the arc shield 12, and the insulating container 1, etc. were silver-soldered, and a vacuum valve having the same configuration as the vacuum valve 100 shown in Fig. 2 was fabricated.

[0039] After cleaning the surfaces of the fixed-side contact 6 of the fixed-side electrode 5 and the movable-side contact 7 of the movable-side electrode 8 by voltage aging or the like, the maximum dielectric breakdown voltage and the maximum interrupting current value were measured, respectively.

[0040] Further, the fabricated electrode material was processed into a disc shape by cutting, and was silver-soldered to the tip of a rod made of oxygen-free copper to fabricate a test electrode. Another identical one was fabricated, and they were placed opposite to each other in a test chamber set to a vacuum degree of about 10 -3 Pa. They were fixed with the electrodes separated by a predetermined gap length, a voltage was applied between the electrodes, and the inter-electrode resistance was estimated from the voltage drop between the electrodes. Also, with the electrodes fixed with a separation of a predetermined gap length, a voltage was applied between the electrodes to measure the initial maximum breakdown voltage. Next, the electrodes were brought into contact and butted against each other, and a current of 15 kA was passed through for a short time with an applied force of about 100 N to artificially weld them. After welding, the test electrodes were opened using a hydraulic cylinder, and the maximum peeling force when opening was measured using a load cell, and this was taken as the welding peeling force. Next, again, with the electrodes fixed with a separation of a predetermined gap length, a voltage was applied between the electrodes, and the maximum breakdown voltage was measured, and this was taken as the insulation withstand voltage characteristic after welding.

[0041] Regarding the general-purpose electrode material Cu75 wt%-Cr25 wt% of Comparative Example 1 measured as described above, the maximum breakdown voltage, maximum interruption current value, inter-electrode resistance, welding peeling force, and insulation withstand voltage characteristic after welding were taken as 1. Each value in the subsequent examples was taken as a standard value.

[0042] Example 1 The contact material for a vacuum valve according to the example is manufactured as follows. Fig. 18 shows a flowchart showing the manufacturing method of the contact material for a vacuum valve according to Example 1. First, Cr is used as the powder raw material of the arc-resistant component, and for example, a skeleton made of the arc-resistant component is formed using a three-dimensional lamination molding method (ST11). Various three-dimensional lamination molding methods can be used, but here, the powder bed fusion bonding method using a laser or an electron beam as a heat source is used. By using the powder bed fusion bonding method, a highly accurate skeleton can be formed. Here, a lattice structure with a 12-coordination structure was obtained as the three-dimensional structure.

[0043] A pure copper plate was added to the formed Cr three-dimensional structure (ST12) and placed still in a refractory crucible installed in a vacuum furnace. The refractory crucible was heated to 10 -3Reduce the pressure to the Pa stage (ST13). Increase the temperature in a reduced-pressure atmosphere, maintain it at 1100 °C to 1300 °C for 30 minutes to 3 hours, infiltrate the melted copper and cast it, (ST14) to obtain a contact material for a vacuum valve. After allowing the contact material for the vacuum valve to cool to room temperature (ST15), take it out and machine it into a predetermined shape (ST16) to obtain an electrode material for a vacuum valve or a contact for an electrode of a vacuum valve.

[0044] Using this contact and the electrode material, in the same manner as in Comparative Example 1, the maximum dielectric breakdown voltage, maximum interrupting current value, interelectrode resistance, welding peel-off force, and insulation withstand voltage characteristics after welding were measured. The results obtained are shown in Table 1 below. As shown in Table 1, the maximum interrupting current value becomes higher. When arcing occurs during current interruption, the surface of the CuCr contact melts, and the more the amount of emission between the electrodes, the lower the current interruption performance. It is considered that the lattice structure of Cr supports Cu, making it difficult for Cu to be emitted between the electrodes even when it melts, improving the maximum interrupting current.

[0045] Example 2 As a three-dimensional structure, except for obtaining a lattice structure having a 12-coordination structure and a parallelepiped structure as a three-dimensional structure by the powder bed fusion method instead of the lattice structure of Example 1, in the same manner as in Example 1, an electrode material for a vacuum valve or a contact for an electrode of a vacuum valve was obtained. In the same manner as in Example 1, the maximum dielectric breakdown voltage, maximum interrupting current value, interelectrode resistance, welding peel-off force, and insulation withstand voltage characteristics after welding were measured. The results obtained are shown in Table 1 below. As shown in Table 1, by adding a parallelepiped structure to the coordination structure, the maximum interrupting current value becomes higher compared to Example 1. From this, it can be seen that the release of molten Cu can be further suppressed.

[0046] Example 3 As a three-dimensional structure, an electrode material for a vacuum valve or a contact of an electrode for a vacuum valve was obtained in the same manner as in Example 1, except that a vertical columnar structure (column diameter 0.2 mm) was used instead of the lattice structure. Similarly, the maximum dielectric breakdown voltage, the maximum cut-off current value, the interelectrode resistance, the welding peel-off force, and the insulation withstand voltage characteristics after welding were measured. The results obtained are shown in Table 1 below. As shown in Table 1, since the interelectrode resistance decreases and the apparent electrical conductivity and thermal conductivity decrease, heat diffusion during current interruption is promoted, so melting of the contact surface is suppressed and the maximum cut-off current is considered to improve.

[0047] Example 4 As a three-dimensional structure, an electrode material for a vacuum valve or a contact of an electrode for a vacuum valve was obtained in the same manner as in Example 1, except that a vertical columnar structure (column diameter 1.5 mm) was used instead of the lattice structure. Similarly, the maximum dielectric breakdown voltage, the maximum cut-off current value, the interelectrode resistance, the welding peel-off force, and the insulation withstand voltage characteristics after welding were measured. The results obtained are shown in Table 1 below. As shown in Table 1, it can be seen that although the interelectrode resistance decreases, when the column diameter is increased, the welding area increases and the insulation withstand voltage characteristics after welding tend to decrease.

[0048] Example 5 As a three-dimensional structure, an electrode material for a vacuum valve or a contact of an electrode for a vacuum valve was obtained in the same manner as in Example 1, except that a horizontal columnar structure (column diameter 0.2 mm) was used instead of the lattice structure. Similarly, the maximum dielectric breakdown voltage, the maximum cut-off current value, the interelectrode resistance, the welding peel-off force, and the insulation withstand voltage characteristics after welding were measured. The results obtained are shown in Table 1 below. As shown in Table 1, the welding peel-off force decreases and the insulation withstand voltage characteristics after welding improve. This is considered to be because the interface between Cu and Cr is relatively easy to peel, so when peeling after the contacts are welded, the interface between Cu and Cr is perpendicular to the pulling direction, resulting in a smaller peel-off force.

[0049] Example 6 As a three-dimensional structure, an electrode material for a vacuum valve or a contact of an electrode for a vacuum valve was obtained in the same manner as in Example 1, except that a porous structure (porosity 50%) was used instead of the lattice structure. Similarly, the maximum dielectric breakdown voltage, the maximum interruption current value, the interelectrode resistance, the welding peel-off force, and the insulation withstand voltage characteristics after welding were measured. The results obtained are shown in Table 1 below. As shown in Table 1, the maximum dielectric breakdown voltage increases due to the presence of the fine three-dimensional network, and the maximum interruption current value increases due to the Cu release suppression effect similar to the lattice structure. Since the porous structure may have lower machining accuracy than the lattice structure, there is an advantage in that the shaping time of the three-dimensional structure can be shortened.

[0050]

Table 1

[0051] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Explanation of Signs

[0052] 6, 7... contacts, 5, 8... electrodes, 20, 101, 304-1, 304-2... contact materials for vacuum valves,... three-dimensional structure, 103... lattice structure, 301... columnar structure, 100... vacuum valve, 104... copper matrix

Claims

1. A contact material for a vacuum valve, comprising copper and at least one arc-resistant component selected from chromium, molybdenum, tantalum, or tungsten, wherein the arc-resistant component has a three-dimensional structure, and at least a part of the copper is provided within the three-dimensional structure.

2. The contact material for a vacuum valve according to claim 1, wherein the three-dimensional structure has a lattice structure, a columnar structure, or a porous structure.

3. The contact material for a vacuum valve according to claim 1, wherein the three-dimensional structure is formed by a metal additive manufacturing method.

4. The contact material for a vacuum valve according to claim 1, wherein the weight ratio of the copper to the arc-resistant component is from 1:0.1 to 1:

2.

5. A vacuum valve comprising an electrode having a contact including the contact material for a vacuum valve according to any one of claims 1 to 4.

6. A material comprising a first component having a three-dimensional structure, and a second component having a composition different from that of the first component, and at least a part of which is provided within the three-dimensional structure.

7. The material according to claim 6, wherein the three-dimensional structure has a lattice structure, a columnar structure, or a porous structure.

8. The material according to claim 6, wherein the three-dimensional structure is formed by a metal additive manufacturing method.

9. A method for manufacturing a contact material for a vacuum valve, comprising forming a three-dimensional structure of at least one arc-resistant component selected from chromium, molybdenum, tantalum, or tungsten, and penetrating molten copper into the interior of the three-dimensional structure.

10. The method according to claim 9, wherein the three-dimensional structure has a lattice structure, a columnar structure, or a porous structure.

11. The method according to claim 9, wherein the three-dimensional structure is formed by a metal additive manufacturing method.

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