JPH0850838A - Contact material for vacuum valve - Google Patents

Abstract

PURPOSE:To provide a contact material for a vacuum valve which can improve a withstand voltage characteristic including a large-cutoff characteristic and the suppression of the restrike generation frequency. CONSTITUTION:A material for at least one of the fixed contact 13a of a fixed electrode 7 separably operated inside a cutoff chamber 1 and the moving contact 13b of a movable electrode 8 has a conductive component having a volume rate of 40 to 75% and comprising at least one kind of Cu or Ag and the remainder of an arc-resistance metal group having the melting point of 1600K or higher. Surface treatment for consuming the surface of a contact is applied thereto.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a contact material for a vacuum valve.

[0002]

2. Description of the Related Art The characteristics required for a contact material for a vacuum valve are three basic requirements shown by performances such as welding resistance, withstand voltage, and breaking, and in addition, temperature rise and 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 to form a contact suitable for a specific application such as for large current or high voltage. Materials have been developed, and those with excellent characteristics have been developed.
The reality is that no contact material for vacuum valves has yet been obtained that fully satisfies the requirements for higher breakdown voltage and higher current.

For example, a CuBi contact (Japanese Examined Patent Publication No. 41-12131) is used as a contact material having a large current and improved resistance to adhesion.
No.) and CuTe contacts (Japanese Patent Publication No. 44-23751). Cu is used as a contact for high current and high breakdown voltage.
Cr contacts are known (Japanese Patent Publication No. 45-35101). Also, C
As a contact with improved welding resistance of uCr contact, Cu
CrBi contacts are known (Japanese Patent Publication No. 61-41091). However, even if the CuCrBi contact is used, in opening and closing a circuit that generates a high voltage such as a capacitor circuit, the withstand voltage characteristic is not sufficient as compared with the CuCr contact, and re-ignition frequently occurs. ing. This means that CuC
Various heat treatments may be applied to the rBi contacts (Japanese Patent Laid-Open No. 4-43521)
), But it can be improved to some extent by controlling the shape of the Cr grains (Japanese Patent Laid-Open No. 5-2955), but there is still room for improvement.

[0004]

As described above, a contact material capable of interrupting a large current and capable of interrupting a high voltage circuit such as a capacitor circuit with a high probability is not always satisfactory. It was The purpose of the present invention is to
Another object of the present invention is to provide a contact material for a vacuum valve, which is capable of interrupting a large current and has improved withstand voltage characteristics including suppression of the frequency of re-ignition.

[0005]

In order to achieve the above object, the first aspect of the present invention is to provide Cu or A having a volume ratio of 40 to 75%.
Conductive component consisting of at least one of g and the balance of 1600K
The gist of the present invention is to have an arc resistant metal component group having the above melting point and a tensile strength of 15 Kgf / mm ² or more.

The second aspect of the present invention has a conductive component having a volume ratio of 40 to 75% and made of at least one of Cu and Ag, and a balance of arc-resistant metal components having a melting point of 1600K or more. However, the gist is that the surface treatment that consumes the contact surface is applied.

[0007]

First, the basic condition of the contact is that the contact has the same breaking ability and withstand voltage characteristics as the existing CuCr contact material. Therefore, V, Nb, which has a getter action comparable to or higher than that of Cr,
At least one of Ta, Y, Ti, Zr, Fe, Ni, Co, W and Mo is used as the arc resistant component. Further, since it is a conductive material, a conductive component based on Cu or Ag is also an essential constituent element. Further, if the conductive component is not added in a constant volume%, the conductivity may be lowered, or the blocking ability may be lowered. In this way, it is the basis of the contact composition that the contact composition is suitable for large current interruption and high withstand voltage.

Next, it is important to achieve higher voltage including suppression of the frequency of re-ignition. Here, the mechanism of occurrence of restriking will be described. Although there are still many unclear points regarding the mechanism of this occurrence, it has been found by research by the inventors of the present invention that they are roughly classified into two types.

That is, one is often observed at the initial stage of opening and closing, and is a factor that is largely dependent on the initial contact surface state. One is a factor that is considered to be caused by the concentration of an electric field due to the roughness of the contact surface or the generation of fine particles as the number of times of opening and closing increases.

With respect to the former, it has been found that a good surface condition can be obtained by subjecting the contact surface to a surface treatment mainly consisting of wear treatment. For the latter, the strength of the contact base metal is improved to prevent the contact base metal from being tripped due to slight welding that occurs between the contacts, and as a result, the contact surface is prevented from becoming rough as the number of times of opening and closing increases. I knew I could do it.

[0011]

EXAMPLES Examples of the present invention will be described in detail below. First, a vacuum valve to which the contact material for a vacuum valve of the present invention is applied will be described with reference to FIGS. 1 and 2. FIG.
FIG. 3 is a configuration diagram of a vacuum valve to which the contact material for a vacuum valve of the present invention is applied. In the figure, 1 is a shut-off chamber,
A metallic lid 4 in which an insulating container 2 formed of an insulating material in a substantially cylindrical shape is provided at both ends via sealing metal fittings 3a and 3b.
A and 4b are vacuum-tight. A pair of electrodes 7, 8 attached to opposite ends of the conductive rods 5, 6 are arranged in the shutoff chamber 1, and the upper electrode 7 is fixed electrode,
The lower electrode 8 is a movable electrode. In addition, the movable electrode 8
A bellows 9 is attached to the conductive rod 6 to enable the electrode 8 to move in the axial direction while keeping the shut-off chamber 1 vacuum-tight. A metallic arc shield 10 is provided above the bellows 9 to prevent the bellows 9 from being covered with arc vapor. Reference numeral 11 denotes a metallic arc shield provided in the interruption chamber 1 so as to cover the electrodes 7 and 8 and prevents the insulating container 2 from being covered with arc vapor.

On the other hand, the electrode 8 is fixed to the conductive rod 6 by a brazing portion 12 as shown in an enlarged view in FIG.
Also, crimping is performed by caulking. The contact 13a is
It is fixed to the electrode 8 by brazing 14. The electrode 7 in FIG. 1 has almost the same structure, and 13b is a fixed contact.

The contact material according to the present invention is suitable for forming both or either of the contacts 13a and 13b as described above. Next, the evaluation method of each contact will be described. (1) Withstand voltage characteristics From the viewpoint of the basic withstand voltage characteristics of each contact material, the withstand voltage of the contact base material was evaluated without considering the influence of the surface treatment.
The evaluated contact points are Comparative Examples 1, 3, 5, 6 and Examples 2, 4, 6-15 described later.

For each contact alloy, a lithographic electrode and a needle electrode, which were mirror-finished by buffing, kept the distance between the electrodes constant at 0.5 mm, and gradually increased the voltage in a vacuum atmosphere of the order of 10-4 Pa to generate sparks. The voltage value at that time was measured to obtain the static withstand voltage value. The measurement data shown in Table 1 is an average value after three repeated tests, and is shown as a relative value when the value of the CuCrBi contact shown in Comparative Example 1 described later is 1.0. (2) Re-ignition characteristics A disc-shaped contact piece with a diameter of 30 mm and a thickness of 5 mm was mounted on a demantable vacuum valve and opened / closed with a 6 KVx500 A circuit. After opening and closing 5,000 times as a whole, the initial re-ignition occurrence rate shown in Table 1 is the re-ignition occurrence probability obtained from the opening and closing of 1-1000 times, and the late re-ignition occurrence rate is 4001-5000 times. It is the probability of re-ignition occurring from opening and closing. The probability of occurrence is shown by the variation width (maximum and minimum) of two circuit breakers (six valves as valves).

[0015]

[Table 1]

Hereinafter, each example and comparative example will be described with reference to Table 1. (Comparative Examples 1 and 2) A C crucible was filled with Cr powder having an average particle size of 100 μm and then, in a vacuum atmosphere of the order of 10 −3 Pa, 1150 ° C. × 1 Hr. Pre-sintering was carried out under the conditions described above to produce a Cr skeleton. After that, 1.0
(Volume%)-Cu block is cut to a predetermined size and washed with acetone, and then, together with a Cr skeleton, in a vacuum atmosphere of the order of 10-3 Pa, 1130 ° C x 0.5 Hr. Was infiltrated under the conditions described above to obtain a CuCrBi contact material having a predetermined composition. After machining into a predetermined shape, the contact of Comparative Example 1 was not subjected to surface treatment, and only the contact of Comparative Example 2 was 10-
After being incorporated into an electric circuit in a vacuum atmosphere of the order of 4 Pa so that the contact serves as an anode, discharge was repeated a plurality of times until the breakdown voltage reached a constant value. The static pressure resistance and re-ignition characteristics of the contacts of Comparative Examples 1 and 2 thus manufactured were evaluated by the method described above. The static withstand voltage value in Comparative Example 1 is the reference value. Comparing Comparative Examples 1 and 2 with each other, although the probability of re-ignition occurring in the initial stage is reduced and improved by the surface treatment, there is not much difference from that in the latter period, and it cannot be said to be sufficient yet. (Comparative Examples 3 and 4) Cr powder having an average particle size of 100 μm and Cu powder having an average particle size of 45 μm were mixed at a ratio of 1: 1 and then,
Was filled in a mold and molded at 7 ton / cm ² molding pressure, 10-3P
a in a vacuum atmosphere of the order of a. Sintered under the conditions of. Further, it was re-molded at a molding pressure of 8 Ton / cm ² and sintered under the same conditions to obtain a contact material. After machining into a predetermined shape, only the comparative example 4 was subjected to the surface treatment under the conditions of the comparative example 2, and the breakdown voltage evaluation of the contacts of the comparative examples 1 and 2 was carried out. Comparative example 4 in which the surface treatment was performed in the same manner as in the relationship of comparative examples 1 and 2.
Was effective in suppressing early re-ignition. initial·
In both the latter stages, the characteristics were better than those of Comparative Examples 1 and 2, and when considered as a product, even a circuit having a capacitor could be used in some cases. (Comparative Example 5, Example 1) After a Cr skeleton was manufactured under the same manufacturing conditions as in Comparative Examples 1 and 2, oxygen-free Cu was used.
Contact materials were obtained by infiltration under the same conditions as in Comparative Examples 1 and 2.
After machining and finishing to a predetermined contact shape, only Example 1 was subjected to surface treatment under the same conditions as in Comparative Example 2. When the breakdown voltage characteristics of these contacts were evaluated, in Comparative Example 5, the re-ignition occurrence probability in the latter period was improved by the improvement in the mechanical characteristics described above, but the initial re-ignition occurrence probability was equivalent to the conventional one. . However, Example 1 in which the surface treatment was performed
Then, the good characteristics were shown in the initial stage as well as in the latter stage. (Example 2-4) Cu such that the volume% of Cr is 50%
A consumable electrode of Cr was made of a laminated plate of Cu and Cr. After fixing the electrode in a consumable electrode type arc melting furnace, vacuuming was performed, and arc melting was performed in an Ar atmosphere of 0.3 Pa. 800 ° C x 3 hr. After removing the supersaturated Cr in the Cu matrix, the contact was obtained by machining into a predetermined shape. 10-4P for the contacts of Example 2
AC discharge was performed in a vacuum atmosphere of the order a, EB irradiation was performed on the contacts of Example 3 in a vacuum atmosphere of the order of 10 −4 Pa, and 10 was applied to the contacts of Example 4.
After being incorporated in an electric circuit so that the contact point becomes a cathode in an Ar atmosphere of -1 Pa, discharge was repeated a plurality of times until the breakdown voltage reached a constant value. The withstand voltage characteristics of the contacts thus manufactured and surface-treated were evaluated. By the effect of surface treatment,
The initial probability of re-ignition was also suppressed, and the probability of occurrence in the latter period was also reduced with the increase in the number of times of opening and closing, which was a good characteristic. With the improvement of mechanical characteristics,
It was smaller than the contact point of the infiltration method. (Examples 5 and 6) HIP treatment was performed using Ar on the solid-state sintering method contacts manufactured under the same conditions as in Comparative Examples 3 and 4. After being machined into a predetermined contact shape, high frequency discharge was carried out in Example 5 in a vacuum atmosphere of the order of 10-1 Pa. Also, for Example 6, 10-1
Laser irradiation was performed in a vacuum atmosphere of the order of Pa.
When the contacts subjected to such a treatment were subjected to withstand voltage evaluation, the re-ignition probability was much better than that of the conventional contacts in both the early and late stages, as in Example 2-4. showed that. (Example 7) The same Cr / Cu powder as in Comparative Examples 3 and 4 was put into a ball mill and sealed with Ar, and then the mixed and crushed powder was subjected to HIP treatment to obtain a contact material. After machining into a predetermined shape, a surface treatment was carried out by laser irradiation in an Ar atmosphere at atmospheric pressure. When the withstand voltage characteristics were evaluated, similar to Example 1-5, good characteristics were shown. (Comparative Example 6, Examples 8, 9 and Comparative Example 7) The same Cr / Cu powder as in Comparative Examples 3 and 4 was used, and the compounding ratios of Cr and Cu were 10:90, 25:75 and 60, respectively. : 40, 90:10 and then mixed in the same manner as in Examples 4 and 5 to obtain contact materials by solid phase sintering and HIP treatment (Comparative Example 6, Example 8, 9 respectively). , Comparative Example 7). After processing into contact shapes, each contact surface was anodized under the same conditions as in Comparative Example 2. With respect to all the contacts, satisfactory results were obtained in terms of withstand voltage, but in Comparative Example 6, the breaking ability evaluated separately,
In Comparative Example 7, it was found that there was a problem in contact resistance and it was difficult to apply at the product level. (Example 10) Nb powder and Cr powder having an average particle size of 100 µm were mixed at a mixing ratio of 9: 1, then pre-sintered under the same conditions as in Comparative Example 5 and further infiltrated to obtain a contact material. It was After machining, after anodizing under the same conditions as in Comparative Example 2, a withstand voltage evaluation was carried out, and good characteristics were obtained. (Example 11) Ta powder having an average particle diameter of 100 µm and V powder were mixed at a mixing ratio of 9: 1, then pre-sintered under the same conditions as in Comparative Example 5 and further infiltrated to obtain a contact material. It was After machining, after anodizing under the same conditions as in Comparative Example 2, a withstand voltage evaluation was carried out, and good characteristics were obtained. Example 12 A Ti powder having an average particle size of 100 μm was surface-coated with a W powder having an average particle size of 6 μm to obtain 10 (volume%) W-Ti composite powder. Cu powder with an average particle size of 45 μm was mixed and mixed in the same volume, and molded under a molding pressure of 8 Ton / cm ² , and then 800 ° C x 1 in a vacuum atmosphere of the order of 10-3 Pa.
Hr. Was carried out. The contact material produced in this manner was processed into a predetermined shape, anodized under the same conditions as in Comparative Example 2, and then subjected to withstand voltage evaluation. As a result, it showed better characteristics than the conventional contact. Example 13 Zr powder having an average particle size of 100 μm was surface-coated with Mo powder having an average particle size of 6 μm, and 10 (volume%) Mo-Z was obtained.
A composite powder of r was obtained. Cu powder with an average particle size of 45 μm was mixed and mixed in the same volume, and molded at a molding pressure of 8 Ton / cm ² , and then 800 ° C. in a vacuum atmosphere of the order of 10 −3 Pa.
x1Hr. Was carried out. The contact material produced in this manner was processed into a predetermined shape, anodized under the same conditions as in Comparative Example 2, and then subjected to withstand voltage evaluation. As a result, it showed better characteristics than the conventional contact. (Example 14) Y powder having an average particle size of 100 μm had an average particle size of 6
The surface was coated with W powder of μm to obtain 10 (volume%) WY composite powder. Cu powder having an average particle diameter of 45 μm and Ag powder were mixed in advance so that the compounding ratio was 8: 2 Ag /
Cu mixed powder and WY composite powder are mixed and mixed in the same volume and molded under a molding pressure of 8 Ton / cm ² , then 10-3P
In a vacuum atmosphere of the order of a, 800 ° C x 1 hr. Was carried out. The contact material produced in this manner was processed into a predetermined shape, anodized under the same conditions as in Comparative Example 2, and then subjected to withstand voltage evaluation. Although a decrease in value was observed,
It showed better characteristics than conventional contacts. (Example 15) Hf powder having an average particle size of 100 µm was surface-coated with Mo powder having an average particle size of 6 µm, and 10 (vol%) Mo-H was used.
A composite powder of f was obtained. Cu powder with an average particle size of 45 μm and A
The Ag powder and the Mo-Hf composite powder, which had been mixed in advance so that the compounding ratio was 8: 2, were mixed and mixed in the same volume by the same amount, and the mixture was molded at a molding pressure of 8 Ton / cm ² , 800 ° C x 1 in a vacuum atmosphere of the order of 10-3Pa
Hr. Was carried out. The contact material produced in this manner was processed into a predetermined shape, anodized under the same conditions as in Comparative Example 2, and then subjected to withstand voltage evaluation. Although a decrease in the value was observed, it showed better characteristics than the conventional contact. (Example 16) Cr powder having an average particle size of 100 μm / average particle size
25 μm Ni / Fe / Co powder and A with an average particle size of 45 μm
g powder to Cr: Ni: Fe: Co: Ag = 35: 5:
After mixing and mixing so as to be 5: 5: 50, 8Ton /
After molding with a molding pressure of cm ² in a vacuum atmosphere of the order of 10 −3 Pa, 900 ° C. × 1 Hr. Was carried out.
After molding with a molding pressure of 8 Ton / cm ² , 10-3
In a vacuum atmosphere of the order of Pa, 900 ° C x 1 hr. Was sintered to obtain a contact material. After machining into a predetermined shape, anodization was performed under the same conditions as in Comparative Example 2, and then withstand voltage evaluation was performed. Similar to Examples 13 and 14, although a relative decrease in withstand voltage value, which was thought to be due to the addition of Ag, was recognized, it showed better characteristics than the conventional contacts.

As described above, the arc resistance components V, C
r, W, Mo, Nb, Ta, Y, Ti, Zr, Hf, F
e, Ni, Co, and Cu, Ag as the conductive component, in any combination of these contact materials, the tensile strength is 15 (Kgf / mm ² ), preferably 25 (Kgf / mm 2
It is clear that by having the above ² ) and applying an appropriate surface treatment, sufficient effect can be obtained for improving the withstand voltage characteristics with the aim of suppressing re-ignition occurrence not only in the initial stage of switching but also in the latter stage. Is.

Further, in the surface treatment applied to the contact surface, it is obvious that the treatment is effective by including the treatment for consuming the contact surface as shown in the embodiment, and the contact treatment is effective. It is obvious that the effect does not change not only immediately after being formed into a shape, but also when it is carried out in a manufacturing process incorporated in a vacuum valve or when it is carried out after being incorporated in a vacuum valve.

Furthermore, for the contact material of the present invention, powder metallurgy such as solid phase sintering, infiltration, arc melting, EB melting, etc.
It is also obvious that various manufacturing methods such as the continuous casting method and the melting method can be applied.

[0020]

As described above, according to the first aspect of the present invention, the arc-resistant material has a volume ratio of 40 to 75%, a conductive component of at least one of Cu and Ag, and the balance having a melting point of 1600K or more. Since it has a metal component group and a tensile strength of 15 Kgf / mm ² or more, it is possible to improve withstand voltage characteristics including a large current interruption characteristic and suppression of the frequency of re-ignition.

According to the second invention, the volume ratio is 40 to
It has a conductive component consisting of at least 75% of Cu or Ag and a balance of arc-resistant metal components having a melting point of 1600K or more. It is possible to improve the withstand voltage characteristics including the cutoff characteristics and the suppression of the frequency of re-ignition.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a vacuum valve to which a vacuum valve contact material of the present invention is applied.

FIG. 2 is a partially enlarged sectional view of FIG.

[Explanation of symbols]

7 ... Fixed electrode, 8 ... Movable electrode, 13a ... Movable side contact, 13b
… Fixed contact

Claims (9)

[Claims] 1. A Cu or Ag having a volume ratio of 40 to 75%.
A contact material for a vacuum valve, characterized in that it has a conductive component consisting of at least one of the above and a balance of arc-resistant metal components having a melting point of 1600 K or higher and a tensile strength of 15 Kgf / mm ² or higher. . 2. Cu or Ag having a volume ratio of 40 to 75%.
And a balance of arc-resistant metal components having a melting point of 1600K or higher, a tensile strength of 15 Kgf / mm ² or higher, and a surface treatment that consumes the contact surface. A contact material for a vacuum valve, which is characterized in that 3. The contact material for a vacuum valve according to claim 1, wherein the tensile strength is 25 Kgf / mm ² . 4. Cu or Ag having a volume ratio of 40 to 75%
A contact material for a vacuum valve, characterized in that it has a conductive component consisting of at least one of the above and a balance arc-resistant metal component group having a melting point of 1600 K or more, and has been subjected to a surface treatment that consumes the contact surface. 5. The arc-resistant metal component group is V, Cr, N.
b, Mo, Ta, W, Y, Ti, Zr, Hf, Fe, C
At least 1 sort (s) of o and Ni is contained, The contact material for vacuum valves in any one of the Claims 1-4 characterized by the above-mentioned. 6. The contact material for a vacuum valve according to claim 2, wherein the surface treatment is an anodic treatment in high vacuum. 7. The contact material for a vacuum valve according to claim 2, wherein the surface treatment is a cathode treatment in a medium and low pressure vacuum. 8. The contact material for a vacuum valve according to claim 2, wherein the surface treatment is performed by either an alternating current treatment or a high frequency treatment. 9. The contact material for a vacuum valve according to claim 2, wherein the surface treatment is a melting treatment.