JP2002161327A - Contact material for circuit breaker, its manufacturing method and circuit breaker - Google Patents

Abstract

(57) [Summary] [Problem] Even when closing at high frequency and high speed,
There is little welding or wear of contact material, suppressing re-ignition phenomenon,
Provided are a contact material for a circuit breaker which can ensure a low contact resistance area and has high reliability, a method for manufacturing the same, and a circuit breaker. A high-conductivity component of at least one of Cu, Ag and Au is 10 to 45% by mass, and at least one arc-resistant component of W, Mo, Cr and a carbide thereof is 50 to 45% by mass.
A contact material containing 90% by mass and at least 0.05% by mass of at least one kind of anti-welding component of Bi, Te, and Sb. The cross-sectional structure of the contact material is 0.0003 m.
a breaker contact material characterized by having a m ² or more highly conductive component phases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a contact material for a circuit breaker,
The present invention relates to a method for manufacturing the same and a circuit breaker, and more particularly to a contact material for a circuit breaker capable of improving the re-ignition characteristics of the contact when used as a contact (contact) of the circuit breaker, a method for manufacturing the same, and a circuit breaker.

[0002]

2. Description of the Related Art A vacuum circuit breaker and a gas circuit breaker automatically open and close an electric circuit in a normal state, and are automatically combined with an overcurrent relay for detecting a failure state when an abnormality such as a grounding accident or a short circuit accident occurs. Power equipment,
Widely used for substation equipment, high-speed railway vehicles, etc.
In particular, the vacuum circuit breaker opens and closes (non-contact, contact) electrical circuits by opening and closing a pair of contact members (contacts) opposed to each other in a container (vacuum valve) maintained at a high vacuum of about 10 ⁻⁴ Pa. ).

FIG. 1 is a sectional view showing an example of the structure of a general vacuum circuit breaker. In FIG. 1, a shut-off chamber 1 in which contact opening and closing operations are performed includes an insulating container 2 made of an insulating material and formed in a substantially cylindrical shape, and sealing metals 3 a at upper and lower ends of the insulating container 2.
It is partitioned and formed by metal lids 4a and 4b provided via the base 3b, and is formed in a vacuum-tight manner. A pair of conductive rods 5 and 6 are arranged in the blocking chamber 1 so as to face each other in the axial direction, and a pair of electrodes 7 and 8 are attached to opposing ends of the conductive rods 5 and 6. . In the figure, the upper electrode 7 is a fixed electrode, while the lower electrode 8 is a movable electrode. A telescopic bellows 9 is mounted on the conductive rod 6 of the movable electrode 8 to enable the movable electrode 8 to reciprocate in the axial direction while the interior of the shut-off chamber 1 is maintained in a vacuum-tight manner. An arc shield 10 made of metal is provided on the bellows 9 to prevent the bellows 9 from being covered with the arc vapor by the arc shield 10.

[0004] A metal arc shield 11 is provided in the cut-off chamber 1 so as to cover the pair of electrodes 7 and 8 facing each other. The arc shield 11 covers the insulating container 2 with arc vapor. Is prevented.

As shown in FIG. 2 in an enlarged manner, the electrode 8 is fixed to a brazing portion 12 formed at the end of the conductive rod 6 by heat bonding or crimped by crimping. The contact member 13a is integrally fixed to the center of the end face of the electrode 8 via a brazing material 14. The fixed-side contact member 13b shown in FIG. 2 is also integrally joined to the end face of the fixed electrode 7 via a brazing material.

According to the vacuum circuit breaker having the above structure, since a high dielectric strength in a high vacuum can be utilized, the opening and closing stroke of the opposed contact member can be shortened.

[0007] The characteristics generally required as a contact material are that the contacts are frequently opened and closed.
Large breaking capacity, (2) high withstand voltage,
(3) small contact resistance, (4) small welding force, (5) small contact wear, (6) small cutting current value, (7) good workability, (8) Have sufficient mechanical strength, and so on. However, in an actual contact material, it is difficult to satisfy all of these characteristics at the same time, and in general, a material that satisfies particularly important characteristics depending on the application and uses some material at the expense of other characteristics is used. That is the current situation.

The contact material must have arc resistance (arc resistance) and welding resistance so as not to be welded by an arc generated when the contacts are frequently opened and closed, while maintaining low contact resistance. In fact, a contact material having arc resistance (arc resistance) and welding resistance is required in order to have high conductive properties. Specific contact constituent materials satisfying both arc resistance and high conductivity include, for example, Ag-based materials, Ag-Cu-based materials, and Ag-based materials.
-CdO-based materials, Cu-W-based materials, Cu-Cr-based materials, and the like. In particular, Cu-W-based contact materials are used in equipment that requires particularly high pressure resistance due to their characteristics.

A vacuum circuit breaker that satisfies these requirements has been developed that satisfies the high required performance each time the power switching control changes. However, if the voltage or current value of the electric circuit increases, the dielectric strength when interrupting the electric circuit becomes insufficient unless the interval between the contacts is widened. On the other hand, it is difficult to increase the interval between the contacts because the speed of the opening / closing characteristics deteriorates.

[0010] Therefore, for the purpose of improving the dielectric strength and high-speed switching characteristics, a vacuum circuit breaker in which the distance between the contacts is further reduced and the distance between the contacts is narrowed has been developed.
It has been put to practical use.

Further, in the vacuum circuit breaker, an arc is generated between the contacts at the time of opening / closing operation. Welding resistance and arc resistance (arc resistance) so that the contact member does not weld to the contact surface of the opposing contact element due to the heat generated by this arc or high current during conduction.
Contact materials have also been developed.

When the contact member is melted and deformed between the narrowed contacts or welded to another portion, the surface of the welded portion further narrows the interval between the contacts. That is,
Since the insulation performance is reduced and the voltage between the contacts facing each other at the time of disconnection is also a high voltage, insulation breakdown occurs and instantaneous conduction occurs, so-called re-ignition occurs.

A technique for suppressing the re-ignition phenomenon is described in, for example, JP-A-10-199379. In this document, by integrating Mo into W as an auxiliary component, the adhesion strength between Cu and W is increased, and Cu-W
A technique for suppressing a re-ignition phenomenon of a system contact material is described.

In the development of the above-mentioned contact materials, a contact material composed of relatively hard W and soft Cu is apt to cause segregation. In order to improve this, finely divided particles were uniformly dispersed. That is, it has been developed and put to practical use as to whether or not the fine high-conductivity component phase and the arc-resistant component phase are to be finely dispersed as uniformly as possible.

[0015]

In recent years, as high-speed railway vehicles and magnetically levitated vehicles (linear motor cars) have approached the practical stage, the traveling distance and traveling speed of the vehicles have come close to practical conditions, and vacuum shut-off has been performed up to now. In the case of the vessel, the following problems further occurred. The magnetic levitation vehicle is provided with a coil array for generating a magnetic field for levitation of the vehicle as a substitute for a road on a road surface.

When the vehicle travels at high speed on this road surface, the opening / closing operation of the vacuum circuit breaker mounted on the vehicle is performed for each coil, and the opening / closing operation speeds up according to the traveling speed of the vehicle. In particular, since a restrike phenomenon occurs in a conventional vacuum circuit breaker, suppression of the restrike phenomenon is strongly demanded by a vehicle engineer.

However, in the conventional contact materials, there has been a tendency for contact materials having a more uniform composition to improve the breaking performance and reliability as described above. In addition, contact materials containing components such as Bi, Te, and Sb are expected to have higher welding resistance, and it is preferable that these component elements be more uniformly dispersed in the structure of the contact material. I was

However, in order to adapt to the harsh usage environment of frequent opening and closing under recent high load,
In particular, with respect to restriking characteristics, further improvement and improvement of the reliability of the contact point itself are required, but there is a problem that they cannot be sufficiently coped with.

The present invention has been made in order to solve the above-mentioned problems, and in particular, even when switching is performed at high frequency and at high speed, there is little welding and consumption of the contact material, and the re-ignition phenomenon is effectively prevented. It is an object of the present invention to provide a highly reliable contact material for a circuit breaker, a method for manufacturing the same, and a circuit breaker that can secure a low contact resistance area.

[0020]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a contact in which a conventional fine high-conductivity component phase and an arc-resistant component phase are uniformly dispersed to suppress a re-ignition phenomenon. Unlike materials, on the other hand, there is a contact material in which a highly conductive component phase is unevenly dispersed.

That is, the contact material for a circuit breaker according to the present invention comprises a high conductive component, an arc-resistant component and a welding-resistant component.
u, Ag and Au at least one highly conductive component
0 to 45% by mass, and 50 to 90% by mass of at least one arc-resistant component of W, Mo, Cr and their carbides;
At least one kind of anti-welding component of Bi, Te, and Sb is used in 0.1%.
A contact material containing at least 0.05% by mass of a high conductive component phase having a sectional area of 0.0003 mm ² or more in the sectional structure of the contact material.

In the above-mentioned contact material, it is preferable that the ratio of the high conductive component phase having a cross-sectional area of 0.0003 mm ² or more to the total high conductive component mass is 5 to 40%.
Further, among the high conductive component phases having a cross-sectional area of 0.0003 mm ² or more, the cross-sectional area is 0.0003 to 0.005 mm ^2.
Is preferably 90% or more.

In the above-mentioned contact material, the thickness of the highly conductive component phase having a cross-sectional area of 0.0003 mm ² or more is 1
It is preferably from 50 μm to 50 μm. Further, it is preferable that the contact material further contains at least one of cobalt, nickel, and iron at 5% by mass or less.

The method for manufacturing a contact material for a circuit breaker according to the present invention is characterized in that at least one kind of welding resistance of a powder containing a high conductive component phase having a cross-sectional area of 0.0003 mm ² or more, an arc resistant component powder, and Bi, Te, Sb. A mixing step of mixing the component powder,
It is characterized by comprising a molding step of molding the mixture mixed in the mixing step, and a sintering step of sintering the molded body obtained in the molding step in a non-oxidizing atmosphere.

In another method for producing a contact material for a circuit breaker according to the present invention, the maximum sectional area is 0.0003 to 0.005.
a mixing step of mixing the powder and the arc-proof component powder containing highly conductive component phase is in mm ^2, a shaping step of shaping the mixed mixture in this mixing step, the molded body obtained by the molding process non A sintering step of sintering in an oxidizing atmosphere and an infiltration step of infiltrating a sintered body obtained by the sintering step with a highly conductive component containing at least one of Bi, Te, and Sb. It is characterized by becoming.

Further, in the above method for producing a contact material,
In the mixing step, it is preferable to add at least one of cobalt, nickel, and iron at 5% by mass or less.

Further, a circuit breaker according to the present invention is a circuit breaker which opens and closes an electric circuit by opening and closing a pair of contacts arranged opposite to each other in a shut-off chamber, wherein the contacts are made of the above-mentioned contact material. It is characterized by the following.

Here, W, Mo, Cr and their carbides as arc resistant components are excellent in arc resistance and welding resistance.
It is a component for extending the life of the contact, and is contained in the raw material mixture in the range of 50 to 90% by mass. If the content is less than 50% by mass, the arc resistance is reduced and it is difficult to extend the life of the contact. On the other hand, when the content exceeds 90% by mass, Cu, Ag,
A relative decrease in the Au content is caused, and an increase in the contact resistance lowers the conduction function as a contact. A more preferred content range of the arc resistant component is 60 to 80% by mass.

Also, Cu, Ag, Au as high conductive components
Has a high electrical conductivity and is contained in an amount of 10 to 45% by mass as a residual component excluding the Cr component and the like and an anti-welding component described later in order to reduce the contact resistance value of the contact. When the content of the highly conductive component is less than 10% by mass, the conductivity is reduced, the contact resistance is increased, and the function as a contact material is reduced. on the other hand,
When the content exceeds 45% by mass, the content of the arc resistant component relatively decreases, and the arc (electric arc) generated at the time of the contact opening / closing operation causes the contact to be easily welded, resulting in reduced wear resistance. The more preferable content range of the high conductive component is 20 to 40% by mass.

The highly conductive components include Cu, silver (A
g), a high conductor made of at least one of gold (Au) and the like and having a high conductivity and a melting point of 900 ° C. or more is preferable. As the arc resistant component, tungsten (W) or molybdenum (Mo), which is a hard metal having a property of not dissolving in the highly conductive component, is preferable.

Bi (bismuth), Te which is a welding-resistant component
(Tellurium) and Sb (antimony) are added in an amount of 0.05% by mass or more in order to improve the welding characteristics of the contact material. These anti-welding components are present at the grain boundaries of the structure of the contact material, reduce the toughness of the contact material, and form a structure that is easily broken, thereby exhibiting the effect of preventing welding of the contact. When the content of the above-mentioned anti-welding component is less than 0.05% by mass, a sufficient effect of adding the component cannot be obtained. On the other hand, even if the content is added so as to exceed 2% by mass, the effect of addition is saturated. Therefore, the content of the anti-welding component is in the range of 0.05 to 2% by mass, but 0.1 to 1.5% by mass.
The range of mass% is more preferable.

The contact material of the present invention is characterized in that, in the metal structure of the sintered body, the matrix of the arc-resistant component phase is mainly composed of a high-conductive component phase (one high-conductive component particle, fine high-conductive By scattering (non-uniformly dispersing) the region where the component particles are aggregated, the aggregate of the fine high conductive component particles, and the aggregate of the fine high conductive component particles, the re-ignition phenomenon occurs even in the high-frequency opening and closing described above. It suppresses and maintains current characteristics, and enables low contact resistance.

The high-conductivity component phase having a predetermined cross-sectional area is one having a cross-sectional area of 0.0003 mm ² or more, such as a single high-conductivity component particle or an aggregate of fine high-conductivity component particles. A plurality of high-conductivity component phases having this cross-sectional area are scattered (non-uniformly dispersed) on the contact surface of the contact. The high-conductivity component phase having the above-mentioned cross-sectional area may be composed of the size of the cross-sectional area of the particles, or may be composed of a region, a lump, or an aggregate in which minute high-conductivity components are aggregated.

The cross section of the high conductive component phase is 0.0003.
If the diameter is less than ² mm, the highly conductive component phase will be more finely dispersed in the metal structure, and as a result, a structure which is uniformly present between the particles of the powder to be the arc resistant component will be formed. Therefore, a continuous arc-resistant component phase is not formed, and characteristics as an arc-resistant component are deteriorated.

On the other hand, if the cross-sectional area is excessively large so as to exceed 0.005 mm ² , it is not preferable because coarse high-conductivity component phases are easily welded between the opposed contacts.

The above sectional area is 0.0003 mm ²
The mass ratio of the high conductive component phase described above is preferably 5 to 40% of the total high conductive component contained in the contact. In this range, it is preferable that the cross-sectional area provided by a plurality interspersed with highly conductive component phases of 0.0003~0.005mm ^2.

With this configuration, the re-ignition phenomenon as a contact material for a circuit breaker can be suppressed, current characteristics can be maintained, and low contact resistance can be realized. When the mass ratio is less than 5%, as in the case where the cross-sectional area is less than 0.0003 mm ² , a highly conductive component phase such as a copper (Cu) phase is finely present between arc-resistant component phases such as W particles. Therefore, it is difficult to obtain a low contact resistance while maintaining a desired current characteristic when the circuit breaker conducts, and the high conductive component phase melts. On the other hand, when the mass ratio exceeds 40%, as in the case where the cross-sectional area exceeds 0.005 mm ² , the case where coarse high conductive components are welded to the contact surface of the opposing contacts increases, so that A re-ignition phenomenon occurs in the switching control of the circuit breaker.

That is, the remaining 60 to 9 of all the high conductive components
The cross-sectional area of the high conductive component of 5 mass% is 0.0003 mm.²
A highly conductive component phase forming a smaller enclosed area,
Continuously and uniformly contained in the voids (holes) of the sintered body by the infiltration process
And a highly conductive component that is immersed. Infiltration of highly conductive components
If there is no object, the former cross-sectional area is 0.0003mm ²
Only the highly conductive component phase forming a smaller enclosed area than
Becomes

In the contact material according to the present invention, the area ratio of the high conductive component phase having a cross-sectional area of 0.0003 to 0.005 mm ² among the high conductive component phases having a cross-sectional area of 0.0003 mm ² or more. Is preferably 90% or more. When the area ratio is less than 90%, a fine high-conductivity component phase exists between the arc-resistant component phases, and it is possible to obtain a low current resistance while maintaining a desired current characteristic when the circuit breaker is turned on. It becomes difficult.

Further, the thickness of the high conductive component phase having a cross-sectional area of 0.0003 mm ² or more is preferably 1 to 50 μm. When the thickness of the high conductive component phase is within the above range, a contact material having both excellent conductive properties and restrike properties can be obtained.

In addition, cobalt (C
By containing at least one of o), nickel (Ni), and iron (Fe) in an amount of 5% by mass or less, the sintering temperature can be lowered, and the production cost can be reduced.

When Cu, Ag, or the like as the high conductive component phase is under the above conditions, the arc-resistant component such as W is correlated as follows.
It has a high-density portion when viewed microscopically, and the high-density portion improves the dielectric strength characteristics, high-speed switching characteristics, withstand voltage characteristics, and arc resistance characteristics of the entire contact as a circuit breaker.

The contact material for a circuit breaker according to the present invention is produced, for example, by the following powder method or infiltration method. First, a predetermined amount of a highly conductive component powder such as Cu, an arc-resistant component powder such as W, a welding-resistant component powder such as Bi, and, if necessary, a transition metal component powder such as Co are blended in a predetermined ratio. The raw material mixture composed of the raw material composition described above is filled in a mold of a press molding machine, and press-molded with a pressing force of about 300 to 1000 MPa to prepare a molded body having a predetermined shape. Temperature in a non-oxidizing atmosphere of 80
By sintering at 0 to 1060 ° C for 0.5 to 3 hours,
Form a sintered body.

The contact material of the present invention can also be manufactured by the following infiltration method. That is, C
An infiltrant is prepared by mixing a highly conductive component such as u and a welding-resistant component comprising at least one of Bi, Te, and Sb by a melting method or a powder mixing method. On the other hand, a method of sintering tungsten (W) powder or the like as an arc-resistant component to form a presintered body having pores and infiltrating the infiltration material into the pores may be employed. Good.

More specifically, by heating the pre-sintered body in a non-oxidizing atmosphere on a highly conductive material such as Cu or Ag containing Bi, Te, Sb or the like. Melts the highly conductive component and the anti-welding component. The molten high conductivity component and welding resistant component are sequentially impregnated into the pores of the pre-sintered body by capillary action, and finally have high bonding strength, excellent arc resistance and wear resistance, and sufficient welding resistance. A contact material having satisfactory current-carrying characteristics is formed. The ratio of the pores formed in the temporary sintered body corresponds to the ratio of copper or the like as a high conductive component.

The W powder and the like as the arc resistant component and the Cu powder and the like as the highly conductive component used in each of the above-mentioned methods for producing the contact material are not particularly limited, but may be generated by the generation of impurity gas in the circuit breaker. It is preferable to use high-purity W powder in order to prevent a decrease in insulation. On the other hand, it is preferable to use electrolytic copper powder as the Cu powder.

In the above method for producing a contact material for a circuit breaker, at least one transition metal component of cobalt (Co), nickel (Ni), and iron (Fe) may be used in the mixing step to lower the sintering temperature. May be added in a small amount.
This addition amount is 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less.

The infiltrated body or sintered body thus formed is processed into a desired shape to form a contact (contact member). The contact is made of a brazing material on the end face of the facing electrode as shown in FIGS. The circuit breaker is formed by joining together using the electrodes and joining the electrodes to which the contacts are respectively joined to the ends of the conductive rods.

The cross-sectional area, mass ratio, area ratio and the like of the high conductive component phase specified in the present invention can be obtained from the contact material for circuit breaker as follows. That is, for each material of the contact material, such as a high conductive component and an arc-resistant component, the cross-sectional structure is observed with a metallographic microscope, and the cross-sectional structure is imaged with a photoelectric conversion device, for example, a CCD camera to obtain an image signal. . This image signal is converted into a digital signal, and the cross-sectional area of a continuous high conductive component phase (high conductive component phase forming a closed region) can be obtained by using an image processing technique.
The above image processing software is PIAS-
III can be suitably used.

The sectional area is 0.0003 to 0.005 mm ²
The measurement range (field of view) of the metal microscope when measuring the cross-sectional area of the highly conductive component phase, the highly conductive component, and the like is 350 × 475.
In the (μm) region, each material component can be measured by moving this visual field. As the image processing technique, a measurement tool (model name VK-
8500) can be used.

According to the correlation between the density of the entire contact material (the material of the high conductivity component and the arc-resistant component) and the value of each component, the high conductivity component phase having a cross-sectional area of 0.0003 mm ² or more among the high conductivity components and the remaining high conductivity component The mass ratio with the component can be easily obtained by the following equation.

[0052]

(Equation 1)

In the above formula, the high conductive component phase area is the area of the entire high conductive component phase having a cross-sectional area of 0.0003 mm ² or more. The high conductive component density is the theoretical density of the high conductive component. For example, in the case of Cu, 8.96 Mg / m ³ , Ag
10.49 Mg / m ³ for Au, 19.32 M for Au
g / m ³ . The theoretical density of W is 19.3 Mg / m ³ .

The total area of the sectional structure is the area of the contact surface of the contact. Further, the material density is the overall density of the highly conductive and arc resistant components. For example, a Cu content of 30% by mass
, And 14.3 Mg / m ³ when the W content is 70% by mass. This material density is 1/1 of the theoretical density of each of the above materials.
(0.3 / 8.96 + 0.7 / 19.3).

The high conductive component ratio is the ratio of the high conductive component contained in the entire contact material.
This is a value determined by chemical analysis using P or the like. The thickness of the high conductive component phase having a cross-sectional area of 0.0003 mm ² or more is selected in the range of 1 to 50 μm. The thickness is measured by polishing and cutting the high conductive component phase portion of the contact material. It can be measured by exposing the surface and observing the exposed surface with a metallographic microscope.

Further, the particle size of the arc-resistant component has a size of 1 to 5 μm. The size is determined by polishing the surface of the contact material to expose the metal structure, It can be measured by observing with a microscope.

[0057]

Next, embodiments of the present invention will be described with reference to the following examples and comparative examples.

As the highly conductive component powder, the average particle size is 30 μm.
m oxygen-free copper powder, 3 μm Ag powder and 10 μm Au
Powder was prepared. On the other hand, as the arc resistant component powder, W powder, Mo powder and Cr powder having an average particle diameter of 3 μm were prepared. Further, antimony (S
b) Powder was prepared.

Next, the above-mentioned high conductive component powder, arc resistant component powder and welding resistant component powder (Sb) were mixed at the ratios shown in Tables 1 to 3 to prepare each raw material mixture. At this time, the energy at the time of mixing was changed in order to variously change the distribution of the maximum cross-sectional area of the high conductive component phase in the metal structure of the finally formed contact material from a distribution where the maximum cross-sectional area becomes large to a distribution where the maximum cross-section becomes small. In general, when the mixing energy is increased, the highly conductive components disperse.
Dispersion does not progress, and a large cross-sectional area is obtained.

Next, a predetermined amount of a binder and a lubricant were further added to each raw material mixture and uniformly mixed for 1 hour to prepare each mixture. Next, each obtained mixture was filled in a mold of a press molding machine, and was molded into a predetermined shape at a pressure of 300 to 400 MPa. Thereafter, each of the obtained molded bodies was sintered at a temperature of 800 ° C. in a hydrogen atmosphere to form each sintered body.
Next, an infiltration process is performed to further impregnate the sintered body with the highly conductive component, and the pores (pores) of each sintered body are impregnated with the highly conductive component. Prepared.

Next, the sectional structure of each prepared infiltrated body was observed with a metallographic microscope, and the sectional structure was imaged with a CCD camera to obtain an image signal. After this image signal is converted into a digital signal, the distribution of the cross-sectional area of the high-conductivity component phase and the mass ratio of the high-conductivity component phase having a cross-sectional area of 0.0003 to 0.005 mm ² to the total high-conductivity component are determined by using an image processing technique. Was measured and calculated, and the results shown in Tables 1 to 3 were obtained.

Each of the infiltrated bodies thus obtained is processed into a desired shape, and the contacts (contact members) 13a, 13 shown in FIGS.
b, and these contacts are integrally joined to the end faces of the electrodes 7 and 8 facing each other by using a brazing material 14.
The vacuum circuit breakers according to Examples and Comparative Examples were assembled by bonding the electrodes 7 and 8 to which the electrodes 13b were bonded to the ends of the conductive rods 5 and 6 in the vacuum valve.

Each of the vacuum circuit breakers assembled as described above was incorporated in an evaluation circuit, and the rate of restriking was measured. In the evaluation circuit, a load resistance of a vacuum circuit breaker and a series connection circuit of a vacuum circuit breaker are connected to an output circuit of a DC power supply having a power supply capacity of 1200 V DC and a DC current of 600 A. The inside of the shutoff chamber 1 was evacuated to a high vacuum of about 10 ⁻⁵ Pa.

Then, the opening / closing control circuit performed vertical opening / closing control (opening / closing control) of the movable electrode 8 on the vacuum circuit breaker of the evaluation circuit at a switching speed of once / second. At this time, the dissociation contact force between the contacts (contact material) 13a and 13b is 2.
5N. When the number of times of opening and closing was 1 × 10 ⁴ times, the rate of occurrence of restriking was measured. The measurement results are shown in Tables 1 to 3 below.
Shown in

The measured value of the re-ignition occurrence rate has been set as a standard by the present inventors so far for each type of contact material (Cu-W type, Ag-Mo type, Ag-W type, etc.). Maximum cross-sectional area of high conductive component phase from 0.0006 to 0.0008 mm
^The relative occurrence rate was determined using the measurement result of the re-ignition occurrence rate by the contact material No. 2 as a reference (reference value 1).

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

As is evident from the results shown in Tables 1 to 3, the content of the highly conductive component is 10 to 45% by mass, the content of the arc-resistant component is 50 to 90% by mass, and the content of the welding-resistant component is 0.1%. 1
% Or less, and has a high conductive component phase having a cross-sectional area of 0.0003 mm ² or more, and a cross-sectional area in the high conductive component of 0.1% or more.
Contact material mass ratio of the high-conductive component phase is 0003～0.005Mm ² is 5-40%, when used as a contact for a vacuum interrupter, with 10 ⁴ times of the opening and closing operations, the incidence of restrike However, as compared with each of the comparative examples showing the conventional examples in which the high conductive component phase was miniaturized, it was significantly reduced, and it was confirmed that excellent breaking performance was exhibited.

That is, according to the contact material of this embodiment, it is possible to achieve both the welding resistance and the pressure resistance without deteriorating the conductive performance, and the arc resistance is high and the re-ignition phenomenon does not occur. In addition, a highly reliable contact material having high welding resistance can be provided.

In the above embodiment, the contact material used for the vacuum circuit breaker has been described as an example. However, the application of the contact material according to the present invention is not limited to the vacuum circuit breaker. It can also be used as a contact material for a circuit breaker, and has the same effect. Also,
Although the contact material prepared by the infiltration method is exemplified in the above-described example, the method for producing the contact material according to the present invention is not limited to this. Is obtained.

[0072]

As described above, according to the contact material for circuit breaker according to the present invention, even when switching is performed at high frequency and at high speed, there is little welding or wear of the contact material, and the occurrence of restriking occurs. Rate is improved (arc resistance is improved), a low contact resistance area is secured, a highly reliable contact material for a circuit breaker is obtained, and a circuit breaker excellent in breaking performance and durability is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a vacuum circuit breaker to which a contact material according to the present invention is applied.

FIG. 2 is an enlarged sectional view showing a contact and an electrode unit shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shut-off room 2 Insulating container (vacuum container, vacuum valve) 3a, 3b Sealing metal 4a, 4b Lid 5 Conductive rod 6 Conductive rod 7 Electrode (fixed electrode) 8 Electrode (movable electrode) 9 Bellows 10 Arc shield 11 Arc shield 12 Brazing portions 13a, 13b Contact member (contact) 14 Brazing material (Ag brazing material)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C22C 27/04 101 C22C 27/04 101 102 102 27/06 27/06 29/06 29/06 BZ 29/08 29 / 08 H01H 1/02 H01H 1/02 ACD F 1/06 1/06 K 11/04 11/04 EZ (72) Inventor Isao Okutomi 1 Toshiba-cho, Fuchu-shi, Tokyo Shibafu Engineering Co., Ltd. (72) Inventor Hiroshi Matsuzawa 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Toshiba Yokohama office (reference) 4K018 AA20 AA22 AA40 AB02 AC01 AD06 AD20 BA01 BA02 BA04 BA13 BA20 DA19 KA34 5G023 AA02 AA04 CA09 CA33 CA35 5G050 AA01 AA03 AA11 AA12 AA13 AA14 AA25 AA29 AA40 AA47 AA51 AA60 BA05 BA06 BA12 CA06 DA03 EA02 5G051 AA12

Claims (9)

[Claims] 1. A high-conductivity component, an arc-resistant component and a welding-resistant component, wherein at least one high-conductivity component of Cu, Ag and Au is contained in an amount of 10 to 45% by mass, and W, Mo, Cr and their carbides are contained. 50 to 90 at least one arc resistant component
A contact material containing at least 0.05% by mass of at least one kind of welding-resistant component of Bi, Te, and Sb, and a high conductivity component having a sectional area of at least 0.0003 mm ² in a sectional structure of the contact material. A contact material for a circuit breaker having a phase. 2. The contact material for a circuit breaker according to claim 1, wherein said contact material further contains at least one of cobalt, nickel and iron in an amount of 5% by mass or less. 3. The ratio of the high conductive component phase having a cross-sectional area of 0.0003 mm ² or more to the total high conductive component mass is 5 to 4.
The contact material for a circuit breaker according to claim 1, wherein the content is 0%. 4. The high conductive component phase having a cross-sectional area of 0.0003 mm ² or more has a cross-sectional area of 0.0003 to 0.005.
^{2. The} contact material for a circuit breaker according to claim 1, wherein the area ratio of the high conductive component phase of mm ² is 90% or more. 5. The shut-off according to claim 1, wherein the thickness of the high conductive component phase having a cross-sectional area of 0.0003 mm ² or more is 1 to 50 μm. Dexterous contact material. 6. A powder containing a highly conductive component phase having a cross-sectional area of 0.0003 mm ² or more, an arc-resistant component powder, and Bi, Te,
A mixing step of mixing Sb with at least one kind of anti-welding component powder, a molding step of molding the mixture mixed in this mixing step, and sintering the molded body obtained in this molding step in a non-oxidizing atmosphere. And a sintering step. 7. A sectional area of 0.0003 to 0.005 mm
² , a mixing step of mixing the powder containing the highly conductive component phase and the arc-resistant component powder, a molding step of molding the mixture mixed in this mixing step, and a molding obtained by the molding step being subjected to non-oxidation. A sintering step of sintering in a neutral atmosphere, and an infiltration step of infiltrating a sintered body obtained by the sintering step with a highly conductive component containing at least one of Bi, Te, and Sb. A method for producing a contact material for a circuit breaker, comprising: 8. The contact material for a circuit breaker according to claim 6, wherein in the mixing step, at least one of cobalt, nickel and iron is added in an amount of 5% by mass or less based on the total mass of the contact material. Production method. 9. A circuit breaker that opens and closes an electric circuit by opening and closing a pair of contacts disposed opposite to each other in a shutoff chamber,
The contact comprises a highly conductive component, an arc-resistant component and a welding-resistant component, contains 10 to 45% by mass of at least one highly conductive component of Cu, Ag and Au, and at least one of W, Mo, Cr and carbides thereof. A contact material containing 50 to 90% by mass of one kind of arc resistant component and 0.05% by mass or more of at least one kind of welding resistant component of Bi, Te, and Sb. A circuit breaker comprising a contact material having a highly conductive component phase of 0.0003 mm ² or more.