JPH09306268A - Contact material for vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance breaking performance by appropriately enlarging an arc that can be produced by breaking. SOLUTION: A contact material for contact electrodes 5, 6 has a conductive component made of at least one kind selected between Ag and Cu and an arc- resisting component made of at least one kind selected from among Cr, Ti, Zr, V, Nb, Ta, W, and Mo, and a plurality of composition regions with different component ratios in the radial direction exist; the difference in the content of the conductive component between the adjacent composition regions is 5 to 50vol%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve contact material having improved breaking performance.

[0002]

2. Description of the Related Art The characteristics required for a contact material for a vacuum valve include three basic requirements as shown in the performances of welding resistance, withstand voltage, and breaking, and in addition, the temperature rise and the contact resistance are low and stable. Is an important requirement. However, it is impossible to satisfy all the requirements with a single metal species because some of these requirements conflict with each other. For this reason, in many practically used contact materials, two or more kinds of elements that complement each other in insufficient performance are combined and suitable for a specific application such as for large current or high voltage. Contact materials have been developed, and materials having excellent properties have been developed.

By the way, there is a strong demand for improving the characteristics of contact materials for the miniaturization of vacuum valves, which is caused by the recent price competition, and this is concentrated on the improvement of the breaking current density. That is, C
From the beginning with the main component of u and the addition of Bi, Te, etc. which are anti-welding components (for example, Japanese Patent Publication No. 61-41091),
A contact (for example, Japanese Examined Patent Publication No. 61-41091) containing an arc-proof component with improved breaking performance such as Cr has come to be used. However, these CuBi · Cu
In a Cr-based contact material, there is a case where interruption is impossible, and one of the causes is that the arc is concentrated on the anode surface as the interruption current increases.

As a method for preventing this, contact materials and electrode materials have been devised in which the vapor pressure, thermophysical properties, etc. are changed stepwise in the radial direction of the contact or electrode surface (for example, JP-A-63-63). 266720).

However, when the composition is changed concentrically in the radial direction as described above, the arc concentration is suppressed to some extent, but when the contact surface after the interruption test is observed, the arc concentration is suppressed. , The arc is not evenly distributed. Therefore, there is still room for improvement in the composition distribution state of the contacts / electrodes so that the concentration of the arc can be further suppressed.

[0006]

As means for suppressing the concentration of arcs, there are cases where the electrode structure is devised in addition to devising the contact material. For example, as disclosed in Japanese Patent No. 1140613, one in which a coil electrode is provided so as to apply an axial magnetic field parallel to the arc axis generated between the electrodes at the time of interruption, and the contact material as described above is also used in combination. is there.

However, even in such a case, it cannot always be said that the arc between the electrodes can be uniformly dispersed, and a large current cannot be reliably cut off.
An object of the present invention is to provide a contact material for a vacuum valve, in which an arc that may occur between electrodes at the time of interruption is appropriately spread and the interruption performance is improved.

[0008]

In order to achieve the above object, the present invention provides a conductive component containing at least one of Ag and Cu, Cr, Ti, Zr, V, Nb, Ta,
There is a plurality of composition regions having an arc resistance component made of at least one of W and Mo and having different component ratios in the radial direction, and the difference in the content of the conductive component in the composition regions adjacent to each other is 5 The gist is to set the volume to 50% by volume.

When the contacts having the same composition were used, there was a tendency for arc concentration to occur on the anode surface as the breaking current increased. One of the possible causes is that if the arc current density on the contact surface is constant, the arc current density in the central part gradually increases due to the cooling of the arc column from the outer peripheral part and the pinch force of the arc itself. Is to increase.

Therefore, in order to previously form a composition distribution in which the arc current density in the outer peripheral portion is larger than that in the central portion, for example, a material composition in which the arc voltage is low for the same breaking current value is concentric. By arranging in the outer peripheral part, the concentration of the arc can be relieved. However,
The arc spread is delicately affected by the composition distribution, and a good breaking test result could not be obtained simply by distributing the composition.

Therefore, the inventors of the present invention found a region of composition distribution that contributes to the improvement of the breaking performance by repeating the production of various samples and the breaking test. As a result, it was found that the gradual change in the composition from the central portion of the contact to the outer peripheral portion is closely related to the breaking performance. That is, on the contact surface composed of a plurality of composition regions, it has been found that if the component difference between the composition regions adjacent to each other is too large, the spread of the arc cannot be performed smoothly. On the other hand, if the component difference is small, it is impossible to achieve a sufficient spread, probably because there is no arc voltage difference enough to transfer the arc. In this way, the breaking current value can be increased by optimizing the composition distribution in the contact.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. First, an example of a vacuum valve to which the vacuum valve contact material of the present invention is applied will be described with reference to FIG.

As shown in FIG. 1, a vacuum container 4 is constructed by hermetically sealing end plates 2 and 3 to openings of both ends of an insulating cylinder 1, and a pair of contact electrodes 5 and 6 are provided inside the vacuum container 4. And the fixed energizing shaft 7 of the contact electrode 5 is airtightly attached to the end plate 2, and the movable energizing shaft 8 of the contact electrode 6 is movably and airtightly attached to the end plate 3 via the bellows 9. . Also,
The contact electrodes 5, 6 are surrounded by an arc shield 10, and a bellows cover 11 of a bellows 9 is attached to the movable energizing shaft 8.

In such a vacuum valve, the movable energizing shaft 8 is operated in the pulling-out direction by an operating mechanism (not shown),
When the contact electrodes 5 and 6 are separated from each other, the arc generated between the contact electrodes 5 and 6 is diffused into the vacuum and cut off when the current zero point is suppressed.

On the opposite side of the contact electrodes 5 and 6,
The contact portion is fixed to the electrode portion by brazing, for example, and the contact material according to the present invention is applied to both or either of these contact portions.

Next, a method of evaluating each contact will be described. (1) Breaking performance For each contact, after incorporating a pair of contacts processed to φ45 mm into a predetermined vacuum valve, the recovery voltage was 7.2 kV
Assuming a constant value, the interruption current was increased from 8 kA in increments of 1 to 1.5 kA, and the possibility of interruption was determined. The characteristics are shown as relative values when the breaking performance of a single composition 50 vol% CrCu contact having no composition distribution is set to 1.0. The evaluation results are shown in Table 1, and with reference to Table 1, each Example and Comparative Example will be considered.

[0017]

[Table 1] Comparative Example 1 Cr powder having an average particle size of 100 μm and Cu powder having an average particle size of 45 μm were used as raw material powders. Predetermined composition (5
0CrCu), mixed and mixed, then diameter 6
A 0 mm carbon crucible was filled with the mixed powder. 10-3P
a in a vacuum atmosphere of the order of a, 1223Kx2Hr.
Sintered under the conditions of. After removing from the carbon crucible, 7
It was molded under a molding pressure of Ton / cm @ 2 and again sintered under the same sintering conditions. Further, molding and sintering were carried out under the same conditions to obtain contacts of 50CrCu.

45 mm diameter for carrying out the breaking test
After being processed into a predetermined shape of No. 3, it was incorporated into a vacuum valve and a breaking test was performed. (Comparative Example 2, Examples 1, 2, 3) Cr powder having an average particle diameter of 100 μm and Cu powder having an average particle diameter of 45 μm were used as raw material powders. Predetermined composition (50CrCu, 47CrCu, 45C
rCu) is mixed and mixed to have a diameter of 60 m
Partition cylinders having diameters of 15 mm and 30 mm, which were manufactured in advance, were arranged concentrically in a carbon crucible of m, and a mixed powder of 50CrCu, 38CrCu, 25CrCu was filled from the outer peripheral portion. After removing the partition cylinder, 10-3P
a in a vacuum atmosphere of the order of a, 1223Kx2Hr.
Sintered under the conditions of. After removing from the carbon crucible, 7
It was molded under a molding pressure of Ton / cm @ 2 and again sintered under the same sintering conditions. Further, molding and sintering were performed under the same conditions to obtain concentric contact points.

45 mm diameter for carrying out the breaking test
After being processed into a predetermined shape of No. 3, it was incorporated into a vacuum valve and a breaking test was performed. (Comparative Example 2) Similarly, from the outer peripheral portion, 50CrCu / 45CrCu /
Example 40 was prepared as 40CrCu, and 50CrCu
Example 2 was prepared as / 38CrCu / 25CrCu. Similarly, 50CrCu / 25CrCu / pure C
Example 3 was prepared as u.

Examples 1, 2, and 3 in which the difference in the amount of the conductive component in each composition region was 5% by volume or more were 1.1 to 1.
Although the barrier performance of No. 2 was shown, Comparative Example 2 in which the difference in the amount of conductive components was as small as 2/3, showed only the same barrier performance as that of the exceptional case 1 to be compared. (Examples 4 and 5) Example 4 in which 50CrCu / 25CrCu / 22CrCu was formed from the outer peripheral portion and 50CrCu / 47CrCu from the outer peripheral portion by the same manufacturing method as in Comparative Example 2.
In Example 5 with 2 / 25CrCu, one of the two composition boundary portions has a small difference in the amount of the conductive component, but the other has a large difference in the amount of the conductive component, so that the spread of the arc spreads smoothly. The blocking performance was 1 times. (Examples 6, 7, and 8) Cr powder having an average particle size of 100 μm and Cu powder having an average particle size of 45 μm were used as raw material powders. After mixing and mixing so as to have a predetermined composition (50CrCu, 25CrCu), a prefabricated partition cylinder with a diameter of 35 mm is concentrically arranged in a carbon crucible with a diameter of 60 mm, and 50 CrCu and 25 CrCu The mixed powder was filled. 10-3 after removing the partition cylinder
1223Kx2H in a vacuum atmosphere of the order of Pa
r. Sintered under the conditions of. After taking out from the carbon crucible, it was molded under a molding pressure of 7 Ton / cm @ 2 and again sintered under the same sintering conditions. Further, molding and sintering were performed under the same conditions to obtain concentric contact points.

45 mm diameter for carrying out the breaking test
After being processed into a predetermined shape of No. 3, it was incorporated into a vacuum valve and a breaking test was performed (Example 6). Manufacturing method similar to that of Example 6
Test pieces were prepared with the composition as the partition cylinders placed in the carbon crucible and having 25 mm and 15 mm, respectively (Examples 7 and 8).

When the breaking test was carried out, the breaking performance was 1.1 times that of Comparative Example 1, and good results were obtained. (Examples 9, 10, 11 and Comparative Example 3) Using the same raw material, manufacturing method, and dimensions as in Example 6, contact points were produced in which the central portion was pure Cu and the outer peripheral portion was 50CrCu. In addition, the diameter of 35 mm at the center of the 50CrCu manufactured in Comparative Example 1.
The sample of Example 10 was manufactured by making holes. The same raw material, manufacturing method, and dimensions as in Example 6 were used, but the central portion was 25 Cr.
Example 11 having Cu and an outer peripheral portion of 60CrCu and Comparative Example 3 having a central portion of pure Cu and an outer peripheral portion of 70CrCu were manufactured.

Although Examples 9, 10 and 11 showed a breaking performance of 1.1 times that of Comparative Example 1, Comparative Example 3 having a large difference in conductive component did not smoothly transfer the arc,
Only the same breaking performance as the conventional contact was obtained. (Comparative Example 4) Another composition system will be examined. Average particle size 3
.mu.m W powder was molded at a molding pressure of 1.5 ton / cm @ 2, and the temperature was 1200 DEG C..times.1 Hr. The W skeleton was manufactured under the sintering conditions of. After loading oxygen-free copper above the W skeleton, 1150 ° C. × 0.5 Hr. Under the conditions described above, it was infiltrated to obtain a 50 W Cu contact, and then processed into a diameter of 45 mm for evaluation (Comparative Example 4).

Evaluations of the following examples are relative values to the breaking test of this contact. (Examples 12, 13, 14) 50 manufactured in Comparative Example 4
A 50 mm diameter 50 WCu was made from the WCu contacts.
Also, in advance, W powder having an average particle size of 3 μ and an average particle size of 10 μm
Cu powder was mixed and mixed at a ratio of 25 WCu, and the powder was filled in a 50 mm mold, and the molding pressure was 7 Ton / cm2.
Molded at 1273K in a hydrogen atmosphere at 1273K.
Sintered to obtain 25WCu. 45mm outside diameter by machining
After processing to an inner diameter of 30 mm, it was combined with the above 50 WCu to obtain a contact having an outer peripheral portion of 25 WCu and an inner portion of 50 WCu (Example 12).

W powder having an average particle size of 3 μ and an average particle size of 10 μm
Cu powder and Bi powder having an average particle size of 44 μm were mixed at 50 W0.
The powder mixed and mixed at a ratio of 1 BiCu was filled in a mold of 50 mm and molded at a molding pressure of 7 Ton / cm2,
Hydrogen powder at 1273K for 1 hr. Sintered 50W0.
1BiCu was obtained. It was machined to a diameter of 30 mm. Also, W powder having an average particle size of 3 μ and an average particle size of 10 μm
Cu powder and Te powder having an average particle size of 44 μm were added at 25 W0.
The powder mixed and mixed at a ratio of 1 TeCu was filled in a mold of 50 mm and molded at a molding pressure of 7 Ton / cm 2, and hydrogen powder at 1273 K for 1 hr. Sintered 25W 0.1
TeCu was obtained. Machined, outer diameter 45 mm, inner diameter 30
mm processed. By combining these contacts, a contact having an outer peripheral portion of 25W0.1TeCu and an inside of 50W0.1BiCu was manufactured (Example 13).

W powder having an average particle size of 3 μ and an average particle size of 10 μm
Cu powder and Bi powder having an average particle size of 44 μm were mixed with 25 W0.
The powder mixed and mixed in the ratio of 3BiCu was filled in a mold of 50 mm and then molded at a molding pressure of 7 Ton / cm 2, and hydrogen powder at 1273 K for 1 hr. Sintered 25W 0.3
BiCu was obtained. It was machined to a diameter of 30 mm. Further, W powder having an average particle diameter of 3 μ, Cu powder having an average particle diameter of 10 μm, and Sb powder having an average particle diameter of 44 μm are mixed with 50 W0.1.
The powder mixed and mixed in the ratio of SbCu was filled in a mold of 50 mm and then molded at a molding pressure of 7 Ton / cm 2, and hydrogen powder at 1273 K for 1 hr. Sintered 25W 0.1T
eCu was obtained. Machined, outer diameter 45 mm, inner diameter 30 m
m processed. By combining these contacts, the outer peripheral portion 2
A contact having 5W0.1SbCu and 50W0.3BiCu inside was manufactured (Example 14).

When the breaking tests of these Examples 12, 13 and 14 were carried out, the breaking performance was 1.1 times that of Comparative Example 4.
As described above, in the contact material formed of a plurality of compositions, by limiting the amount of change in the amount of the conductive component at the composition boundary portion to 5 to 50% by volume, a better breaking performance than that of the conventional uniform composition contact is obtained. It is clear that it will be obtained.

It is also clear that the use of other arc resistant materials not described in this example will also improve the barrier performance. Furthermore, it is clear that similar results can be obtained using this material as an electrode material.

[0029]

As described above, according to the present invention, a conductive component composed of at least one of Ag and Cu and C
r, Ti, Zr, V, Nb, Ta, W, and Mo, and an arc resistance component, and a plurality of composition regions having different component ratios in the radial direction are present and are adjacent to each other. The difference in the content of the conductive component in the composition region is 5 to
Since it is set to 50% by volume, the arc can be appropriately expanded and the breaking performance can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a vacuum valve to which a contact material for a vacuum valve of the present invention is applied.

[Explanation of symbols]

4 ... Vacuum container, 5, 6 ... Contact electrode, 7 ... Fixed energizing shaft, 8
... Movable energizing shaft

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Atsushi Yamamoto 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Toshiba Fuchu Plant Co., Ltd.

Claims (6)

[Claims] 1. A conductive component composed of at least one of Ag and Cu, and Cr, Ti, Zr, V, Nb, and T.
a, W and Mo, and a plurality of composition regions having different composition ratios in the radial direction, and having a content of the conductive component in the composition regions adjacent to each other. A contact material for a vacuum valve, wherein the difference is 5 to 50% by volume. 2. A conductive component made of at least one of Ag and Cu, and Cr, Ti, Zr, V, Nb, and T.
a, W and Mo, and a plurality of composition regions having different composition ratios in the radial direction are present, and the innermost composition region is made of pure Cu and adjacent to each other. The contact material for a vacuum valve, wherein the difference in the content of the conductive component in the composition region is 5 to 50% by volume. 3. The vacuum according to claim 1, wherein the conductive component amount in the plurality of composition regions existing in the radial direction is reduced toward the composition region of the outer peripheral portion. Contact material for valves. 4. The amount of the conductive component in each composition region is 25% by volume or more, and the outermost composition region has the arc resistance component of 60% by volume or less and the balance substantially the conductive component. The contact material for a vacuum valve according to any one of claims 1 to 3. 5. A conductive component composed of at least one of Ag and Cu, and Cr, Ti, Zr, V, Nb, and T.
a, W and Mo, and a plurality of composition regions having different composition ratios in the radial direction are present, and the innermost composition region portion is hollow and adjacent to each other. The contact material for a vacuum valve, wherein the difference in the content of the conductive component in the composition region is 5 to 50% by volume. 6. Each of the composition regions contains at least one of Bi, Te and Sb in an amount of 1% by volume or less with respect to the conductive component. The contact material for a vacuum valve according to Crab.