JP2002256361A - Contact material for vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a contact material for a vacuum valve the phenomena of the covering of electrically conductive components onto arc resistance componential grains, the depression of the electrically conductive components to the circumferences of the arc resistance componential grains, and the falling- off of the arc resistant componential grains are reduced and which is provided with good cut-off performance and withstand voltage performance. SOLUTION: The material contains electrically conductive components essentially consisting of at least one kind selected from Ag and Cu and arc resistant components provided with at least one kind selected from Cr, W, Nb, Ta, Ti and Mo, and the carbides thereof. The melting depth of a conducting surface is defined as 0.001 to 2 mm, and the maximum roughness of the conducting surface is defined as <=3 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a contact material for a vacuum valve.

[0002]

2. Description of the Related Art In a power system, a circuit breaker is generally provided in order to prevent the spread of accidents. One of such circuit breakers is a vacuum circuit breaker in which an insulating medium in an opening and closing section is vacuum. The vacuum circuit breaker is
The vacuum valve comprises an opening / closing unit and an operating mechanism for operating a pair of electrodes which can be brought into contact with and separated from each other and which is provided in a vacuum container of the vacuum valve. The characteristics required of the contact material of the pair of electrodes of the vacuum valve include contact resistance characteristics and temperature rise characteristics, in addition to the three basic requirements of cut-off characteristics, withstand voltage characteristics and welding resistance characteristics. A vacuum valve contact material having all these properties is ideal, but it is difficult to satisfy all the properties with a single metal species because these properties have contradictory properties. is there. For this reason, contact materials for vacuum valves that have been put to practical use are composed of a combination of two or more elements that can mutually compensate for the insufficient properties, for example, a conductive component and an arc-resistant component, and are used for large currents and high voltages. It is used according to a desired use such as. On the other hand, among various types of contact materials for vacuum valves, those having relatively satisfactory characteristics are described in, for example, Japanese Patent Application Laid-Open No. 54-71375.
As described in the publication, Cu as a conductive component
And a contact material for a Cu-Cr vacuum valve made of Cr as an arc-resistant component. According to the publication, Cu having high current performance is added to compensate for the property of Cr that exhibits excellent withstand voltage characteristics in a vacuum but cannot be expected to have high current performance.
Cr, particularly Cr having an average particle diameter of 100 μm or less, is uniformly dispersed in the matrix, and various characteristics such as blocking performance and withstand voltage performance can be improved.

[0003]

However, in the conventional contact material for a Cu-Cr based vacuum valve, the mechanical strength such as hardness, tensile strength, toughness, etc. of the conductive component and the arc-resistant component is greatly different. When processing the surface of the contact material into a predetermined shape, covering of the conductive component on the arc resistant component particles,
Phenomena such as dents of the conductive component around the arc resistant component particles or falling off of the arc resistant component particles may occur. These phenomena adversely affect the breaking performance and the like, and it is not possible to obtain various characteristics satisfactory as a contact material for a vacuum valve. An object of the present invention is to cover the conductive component on the arc-resistant component particles when processing the surface of the contact material into a predetermined shape, to dent the conductive component around the arc-resistant component particles or to form the arc-resistant component particles. An object of the present invention is to provide a vacuum valve contact material that can reduce the occurrence of a phenomenon such as falling off and obtain good breaking performance and withstand voltage performance.

[0004]

In order to achieve the above object, the invention according to claim 1 comprises a conductive component containing at least one of Ag and Cu as a main component and Cr, W, Nb, Tb.
a, Ti, Mo and at least one of these carbides
And an arc-resistant component having a seed, wherein the depth at which the energized surface is melted is 0.001 mm or more and 2 mm or less, and the maximum roughness of the energized surface is 3 μm or less. This can reduce the occurrence of phenomena such as covering of the conductive component on the arc-resistant component particles, dent of the conductive component around the arc-resistant component particles, or falling off of the arc-resistant component particles. The invention according to claim 2 provides a conductive component containing at least one of Ag and Cu as a main component and Cr, W, Nb, Ta,
An arc-resistant component comprising at least one of Ti, Mo and these carbides, and a ratio x of the arc-resistant component;
The ratio yn occupied by the arc-resistant component in a predetermined area of 1 mm ² or more and 0.01 mm or less on the current-carrying surface is 0.1% by weight.
It is characterized in that a relationship of 9 ≦ yn / x ≦ 1.1 is satisfied.
This makes it possible to obtain a contact material for a vacuum valve capable of obtaining good breaking performance and withstand voltage performance.

[0005]

Embodiments of the present invention will be described below in detail. FIG. 1 is a sectional view of a vacuum valve to which the contact material for a vacuum valve of the present invention is applied. In the figure, reference numeral 1 denotes a shut-off chamber. The shut-off chamber 1 includes an insulating container 2 formed of an insulating material in a substantially cylindrical shape, and a metallic lid provided at both ends thereof through sealing fittings 3a and 3b. Body 4a,
4b are vacuum-tight. In the shut-off room 1,
A pair of electrodes 7 and 8 attached to opposing ends of the conductive rods 5 and 6 are provided, and the upper electrode 7 is a fixed electrode and the lower electrode 8 is a movable electrode. A bellows 9 is attached to the conductive rod 6 of the movable electrode 8 to enable the movable electrode 8 to move in the axial direction while keeping the inside of the shut-off chamber 1 vacuum-tight. A metallic first arc shield 10 is provided on the bellows 9 to prevent the bellows 9 from being covered with the arc vapor. Reference numeral 11 denotes a metallic second arc shield provided in the shut-off chamber 1 so as to cover the fixed electrode 7 and the movable electrode 8, and prevents the insulating container 2 from being covered with the arc vapor. On the other hand, the movable electrode 8 side
As shown in FIG. 2, the conductive rod 6 is fixed to the conductive rod 6 by a brazing portion 12, or is connected by crimping. The movable contact 13 a is fixed to the movable electrode 8 by brazing 14. The fixed contact 13b on the fixed electrode 7 side is the same as the movable contact 13b in FIG.
It is stuck to.

When a contact material for a vacuum valve, for example, a Cu—Cr-based contact material is processed into a predetermined shape on the surface of the contact material, the conductive component is covered on the arc-resistant component particles.
By reducing the occurrence of phenomena such as dents of the conductive component around the arc-resistant component particles or falling off of the arc-resistant component particles, good breaking performance and withstand voltage performance can be obtained. The present inventors have discovered that there is a close relationship between the reduction of the above-described phenomenon and the miniaturization and maximum roughness of the cross-sectional structure near the current-carrying surface. In particular, on the current-carrying surface, after processing the contact into a predetermined shape, the contact is melted to a depth of 0.001 mm or more and 2 mm or less from the surface to make it finer and have a maximum roughness of 3 μmm. In this way, on the current-carrying surface, 0.001 mm or more from the surface 2
mm to a depth of less than 3 mm
When the thickness is set to μ mm, the unevenness of the surface is reduced, and the composition ratio of the current-carrying surface is equal to the composition ratio of the entire contact. In particular, according to the study by the present inventors, the ratio yn of the arc-resistant component in a predetermined region of 1 mm ² or more and 0.01 mm or less in the current-carrying surface is 0.9 ≦ yn / x ≦ by weight. If the variation of the composition ratio on the current-carrying surface and the contact as a whole is reduced to 1.1, the breaking performance and the withstand voltage performance are improved.

More specifically, the relationship with each of the phenomena described above will be described.
When you look at it, the covering of the conductive component on the arc resistant component particles
Is because the conductive component is softer and has a larger elongation than the arc resistant component.
Is a phenomenon that occurs in the
As it decreases, yn becomes smaller than x. In addition, arc resistant
The dent of the conductive component around the particle is the machinability of the arc resistant component
Is a phenomenon that occurs because it is better than the conductive component
Since the base arc-resistant component particles appear on the current-carrying surface, yn is equal to x.
Larger. Furthermore, the falling off of the arc resistant component particles
If the binding force between the particles and the conductive component matrix is weak,
For example, it is likely to occur when manufactured by the sintering method, especially the solid-state sintering method.
Therefore, yn is smaller than x. Therefore, arc resistance
Covering of conductive component on separating particles, around arc-resistant component particles
Phenomena such as dents in the conductive component and falling off of the arc resistant component particles
1 mm ²The depth is 0.0
Ratio y of the arc-resistant component in a predetermined area of 1 mm or less
n has a relation of 0.9 ≦ yn / x ≦ 1.1 in weight ratio.
The variation of the composition ratio on the current-carrying surface and the entire contact
It is possible to reduce the
Withstand voltage performance is obtained. Here, the vacuum valve
Cu-Cr based material used as vacuum valve contact material
Taking the contact material as an example, for the vacuum valve according to the present embodiment
Method of manufacturing contact material and measurement of breaking characteristics and static withstand voltage characteristics
The results will be described with reference to Table 1.

[0008]

[Table 1] (Comparative Example 1 to Comparative Example 2, Example 1 to Example 3) Comparative Example 1
Manufactured a Cu-50Cr contact by a solid phase sintering method. C
The u powder and the Cr powder were mixed at a weight ratio of 1: 1 and filled in a crucible of φ60 mm, and then sintered under a vacuum of the order of 10-3 Pa at 1000 ° C. for 5 hours. Next, the obtained sintered body was subjected to 10 t / cm with a φ60 mm mold.
2 and then sintered again under the same conditions to obtain Cu-50C
An r alloy was obtained. This Cu-Cr alloy is formed into a predetermined contact shape (φ
After processing into a vacuum valve (50 mm, t5 mm), a cutoff test was performed. In the interruption test, the maximum interruption current was measured by gradually increasing the current value from 5 kA. In addition, in parallel with the cutoff test, the static pressure
(Combination of needle electrode and plate electrode). In the static withstand voltage test, the breakdown voltage was measured five times while keeping the electrode interval constant.
The average was calculated. Based on the measurement results of Comparative Example 1, the other measurement results are shown as relative values. Table 1
Is calculated after measuring yn and x by different methods. Y, which is the ratio of the arc resistant component of the conducting surface
For n, the area ratio between the conductive component and the arc-resistant component was measured from an enlarged photograph of the energized surface (about several tens times) and converted to a weight ratio. This measurement was performed five times at different positions, and the maximum and minimum values were recorded. When the particle diameter of the arc-resistant component was as small as several tens of μm, the weight ratio was measured with an EDX attached to an electron microscope (this method was also measured five times at different positions). Further, x, which is the arc resistance component ratio of the entire contact, was measured by wet analysis. Values obtained by dividing the maximum value or the minimum value of yn by x are 0.92 and 1.12 shown in Table 1.

In Example 1, a Cu-50Cr alloy was produced in the same process as in Comparative Example 1, processed into a predetermined shape, and then subjected to a current-carrying surface (a cut-off surface in the case of a contact for a break-off test, and a test piece for a static withstand voltage). Was irradiated with an electron beam (injection energy is, for example, 1 W / mm ² ), Cu and Cr were melted and refined, and a cutoff test and a static pressure test were performed. Y after electron beam irradiation
n / x was 0.96 to 1.07, and the breaking performance and the withstand voltage performance were 1.2 times and 1.1 times of Comparative Example 1, respectively. In Example 2 and Example 3, Cu-50Cr alloy was used in Comparative Example 1
After processing in the same process and processing into a predetermined shape, the current-carrying surface was melted to make Cu and Cr finer, and a cutoff test and a static withstand voltage test were performed. In Example 2, when melted by laser irradiation (injection energy is, for example, 2 W / mm ² ), yn / x is 0.91 to 1.05, and the breaking performance and static withstand voltage performance are the same as those of Comparative Example 1. It was 1.3 times and 1.0 times. Further, in Example 3, after the contact for the interruption test was assembled in the vacuum valve, it was melted by energizing several hundred A and opening and closing 50 times, and a voltage of several tens kV was applied to the static withstand voltage test piece. When melted by applying 10 times for 10 seconds, yn / x was 0.93 to 1.04, and the breaking performance and static withstand voltage performance were 1.3 times and 1.3 times that of Comparative Example 1.
It was one time.

In Comparative Example 2, a Cu-50Cr alloy was produced in the same process as in Comparative Example 1, processed into a predetermined shape, and irradiated with an electron beam for a longer time than in Example 1.
And the Cr content increased due to evaporation of yn /
The maximum value of x was 1.15, and the breaking performance and the withstand voltage performance were 1.2 times and 0.9 times of Comparative Example 1. (Comparative Examples 3 to
Comparative Example 4, Example 4 to Example 5) In Comparative Example 3 to Comparative Example 4 and Example 4 to Example 5, a Cu-40Cr alloy produced by a solid phase sintering method in a hydrogen atmosphere was processed into a predetermined shape. Thereafter, the injection energy for melting the energized surface was adjusted, and the melting depth was used as a parameter. In addition, energy is Cu-40.
Cr was injected by generating an arc. In Comparative Example 3, the melting depth from the surface was about 0.0008 mm, and the breaking performance and withstand voltage performance were almost the same as Comparative Example 1. In Example 4 and Example 5, the melting depths were 0.002 mm and 1.5 mm, respectively, and the breaking performance and withstand voltage performance were 1.1 to 1.2 times that of Comparative Example 1 and were slightly improved. . In Comparative Example 4, the melting depth was 2.2 mm, which was about half of the contact thickness, and the contact side surface was broken during assembly of the vacuum valve, so the test was stopped. This crack is considered to have occurred due to a difference in material properties (hardness, coefficient of thermal expansion, etc.) between the molten fine layer and the substrate.

(Comparative Example 5, Examples 6 to 7) In Comparative Example 5 and Examples 6 to 7, Cu-55
After preparing a Cr alloy and processing it into a predetermined shape, the injection energy of the electron beam when melting the energized surface and the cooling rate when solidifying were adjusted, and the particle size of the Cr particles in the fine layer was used as a parameter. . The Cu-55Cr alloy is formed by pressing a Cr powder under pressure and then sintering it under a condition of 1150 ° C. * 1 hour in a hydrogen atmosphere. It was produced by heating at 1150 ° C. in an atmosphere to infiltrate Cu as a conductive component.
In Comparative Example 5, the Cr particle diameter was about 70 μm, the maximum value of yn / x was 1.12, and the breaking performance and the withstand voltage performance were 0.9 and 1.1 times that of Comparative Example 1, respectively. In Example 6, the Cr particle diameter was about 40 μm, and yn / x was 0.95 to 1.
08, and the breaking performance and the withstand voltage performance were 1.1 times and 1.2 times that of Comparative Example 1, respectively. In Example 7, the Cr particle diameter was about 10 μm, yn / x was 0.97 to 1.05,
The breaking performance and withstand voltage performance were 1.2 times and 1.3 times that of Comparative Example 1, respectively. (Comparative Example 6, Examples 8 to 11) Comparative Example 2 described above
In Comparative Example 5 and Examples 1 to 7, the case where the energized surface was melted after processing the Cu-Cr alloy into a predetermined shape was described. In Examples 8 to 11, the energized surface was mechanically smoothed. As a result, yn / x is set to 0.9 to 1.1 to improve the contact characteristics.

In Comparative Example 6, when a Cu-20Cr alloy produced by liquid phase sintering in a vacuum atmosphere was processed into a predetermined shape, the maximum roughness of the energized surface was 5 μm, and the maximum value of yn / x was 1. 13 and the breaking performance and the withstand voltage performance were Comparative Example 1.
Were 1.0 times and 0.9 times, respectively. In Example 8,
After processing the Cu-20Cr alloy produced in the same process as in Comparative Example 6 into a predetermined shape, only the current-carrying surface was subjected to the bite feed rate,
As a result of the special grinding processing with the adjusted angle, the maximum roughness of the energized surface was reduced to 3 μm, yn / x was 0.95 to 1.08, and the breaking performance and the pressure resistance performance were 1. 2
And 1.1 times. In Example 9, after the Cu-20Cr alloy produced in the same process as Comparative Example 6 was processed into a predetermined shape, only the energized surface was polished with emery paper. As a result, the maximum roughness of the energized surface was reduced to 2 μm, and yn / X is 0.96 to 1.
06, and the breaking performance and the withstand voltage performance were 1.3 times and 1.2 times of Comparative Example 1, respectively. Example 10 is Comparative Example 6
After the Cu-20Cr alloy produced in the same process as above was processed into a predetermined shape, only the current-carrying surface was polished with a paste containing diamond powder. As a result, the maximum roughness of the current-carrying surface was reduced to 1 μm, and yn / x was reduced to 0.3. 97 to 1.04, and both the breaking performance and the withstand voltage performance were 1.3 times that of Comparative Example 1.

In Example 11, after the Cu-20Cr alloy produced in the same process as Comparative Example 6 is processed into a predetermined shape, the current-carrying surface is irradiated with an ion beam (injection energy is, for example, 0.5 W / mm ² ). As a result of melting and further polishing with alumina powder, the maximum roughness of the energized surface was reduced to 1 μm, and y
n / x was 0.98 to 1.03, and the breaking performance and withstand voltage performance were 1.4 times and 1.3 times of Comparative Example 1, respectively. (Comparative Examples 8 to 9 and Examples 12 to 13) In Comparative Examples 1 to 7 and Examples 1 to 11 described above,
The sintering temperature was 1000 ° C., 1100 ° C., and 1150 ° C., that is, sintering was performed at a temperature within ± 90 ° C. based on the melting point of the conductive component Cu (1083 ° C.). In Examples 12 and 13, the sintering temperature was 900
950 ° C, 1200 ° C, 1300 ° C, Cu-25
A Cr alloy was manufactured. Among them, in Comparative Example 9 sintered at 1300 ° C., Cu and Cr were separated, so it was judged that the electrical evaluation of the contact was not worthy. The remaining three types of Cu-25C
After processing the r alloy into a predetermined shape, the energized surface was melted by irradiation with an ion beam. In Comparative Example 8, y
Although n / x was 0.98 to 1.03, the breaking performance and the withstand voltage performance were 1.0 times and 0.9 times of Comparative Example 1, respectively. This is because the sintering did not proceed due to the low sintering temperature and the density was low (relative density 85%).

In Embodiment 12, yn / x is 0.96 to 1.
08, and the breaking performance and the withstand voltage performance were 1.1 times and 1.0 times of Comparative Example 1, respectively. In Example 13, yn /
x was 0.94 to 1.06, and the breaking performance and the withstand voltage performance were 1.2 times and 1.1 times of Comparative Example 1, respectively. (Examples 14 to 19) In Comparative Examples 1 to 9 and Examples 1 to 13 described above, the Cu-Cr contact material in which the arc resistant component is Cr and the conductive component is Cu has been described. In Example 14, a Cu-20 wt (% by weight)% W contact having W as the arc resistant component and Cu as the conductive component was used. Thus, in Example 14, after processing into a predetermined shape, the current-carrying surface was melted and manufactured, and the breaking performance and the withstand voltage performance were evaluated. (Cu-W contacts) 1.2 times and 1.0 times the Cu-W contacts manufactured by the ordinary solid phase sintering method without passing through the (current-carrying surface melting step).
It was one time. In Examples 15 to 17, the arc resistant components were Nb, WC, and Cr + W, respectively, and the conductive component was Cu.
As a contact material was manufactured under the same conditions as in Example 14,
As a result of evaluating the breaking performance and the withstand voltage performance, Examples 15 to
In all of Examples 17, the breaking performance was 1.2 times and the static withstand voltage performance was 1.1 times as compared with the contacts manufactured by the ordinary solid phase sintering method without passing through the energizing surface melting step. It was twice.

In Examples 18 to 19, contact materials were manufactured under the same conditions as in Example 15 with the conductive components being Ag and Ag + Cu and the arc resistant component being WC, respectively, and the electrical characteristics were evaluated. In both Examples 18 and 19, the breaking performance was 1.3 times and the static withstand voltage performance was 1.3 times that of the contacts manufactured by the normal sintering and infiltration method without passing through the energized surface melting step. It was 1.2 times. (Examples 20 to 22) In the comparative examples 1 to 9 and the examples 1 to 19, the contact material composed of the conductive component and the arc-resistant component was described. In Example 22, Bi, Te, and Te were used as auxiliary components, respectively.
+ Se was added, a contact material was manufactured under the same conditions as in Example 14, and the electrical characteristics were evaluated. As a result, all of Examples 20 to 22 were subjected to a normal solid-phase sintering method that did not pass through the step of melting the energized surface. Breaking performance is 1.
It was twice, and the withstand voltage performance was 1.1 times. As the above results show, the contact material for a vacuum valve according to the present embodiment is compared with the reference contact material of Comparative Example 1 as a reference.
Breaking performance and static withstand voltage performance can be improved. In the present embodiment, the arc resistance component is Cr, W,
There are only Nb, WC, Cr + W, but Cr, W, N
The same effect can be obtained by using at least one of b, Ta, Ti, Mo and their carbides as an arc-resistant component.

Further, in this embodiment, there is only the description of Cu, Ag, Ag + Cu for the conductive component, but the same effect can be obtained if Cu or Ag is the main component.
Further, regarding the auxiliary component, in the present embodiment, B
There are only descriptions of i, Te, Te + Se, but Bi, Te,
Similar effects can be obtained by using at least one of Se, Sb, and Co as an auxiliary component.

[0017]

As described above, according to the present invention, it is possible to obtain a contact material for a vacuum valve having excellent breaking performance and withstand voltage performance.

[Brief description of the drawings]

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

FIG. 2 is an enlarged sectional view of a movable electrode 8 in FIG.

[Explanation of symbols]

7: fixed electrode, 8: movable electrode, 13a: movable contact, 1
3b ... fixed side contact

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01H 1/02 H01H 1/02 A C 33/66 33/66 B // C22C 32/00 C22C 32/00 A B (72) Inventor Takashi Kusano 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Toshiba Fuchu office, Inc. AA02 AA04 AB02 AC01 BA01 BA02 BA03 BA04 BA09 BA20 BB04 DA11 FA10 KA34 4K020 AA22 AC04 AC05 BB29 5G026 BA01 BA02 BB02 BB04 BB10 BB12 BB14 BB15 BB16 BB17 BB18 BB24 BB25 BB27 AAAAAAAAAAAAAAA1A CA01 DA03 EA02 EA06

Claims (4)

[Claims] 1. A conductive component mainly composed of at least one of Ag and Cu, and Cr, W, Nb, Ta, Ti,
Mo and an arc-resistant component comprising at least one of these carbides, and the depth at which the current-carrying surface is melted is 0.00
1 mm or more and 2 mm or less, and the maximum roughness of the energized surface is 3
A contact material for a vacuum valve, characterized in that the thickness is less than μm. 2. A conductive component mainly composed of at least one of Ag and Cu, and Cr, W, Nb, Ta, Ti,
Mo and an arc-resistant component comprising at least one of these carbides, and a ratio x of the arc-resistant component, and a predetermined area having a depth of 1 mm ² or more and 0.01 mm or less on the conducting surface. A contact material for a vacuum valve, wherein a ratio yn (n is a suffix of y) occupied by an arc-resistant component is in a relationship of 0.9 ≦ yn / x ≦ 1.1 by weight. 3. The contact material for a vacuum valve according to claim 1, wherein the arc-resistant component has an average particle diameter of 50 μm or less. 4. When the content is 5% by weight or less and Bi, T
4. The contact material for a vacuum valve according to claim 1, further comprising an auxiliary component having at least one of e, Se, Sb and Co.