JP2002042616A - Vacuum circuit-breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum circuit-breaker having the stabilized contact resistance characteristic and the excellent large current breaking characteristic. SOLUTION: In a Cu-Cr contact mounted on the vacuum circuit-breaker, a part of a contact surface area is formed of a first CuCr group formed of a plurality of Cr particles having the particle diameter >40 μm and Cu phase surrounding the particles, and a second CuCr group formed of a plurality of Cr particles having the particle diameter <10 μm and Cu phase surrounding the particles, the contact surface area is formed of a plurality of aggregates comprising the first CuCr group and the second CuCr group, and the contact surface area constitutes a part of or the whole of a section of the contact. The stabilized contact resistance characteristic and the excellent large current breaking characteristic can be obtained thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum circuit breaker provided with a contact material having both a contact resistance characteristic and a large current breaking characteristic.

[0002]

2. Description of the Related Art The contacts of a vacuum valve for interrupting current in a high vacuum by utilizing arc diffusivity in a vacuum are composed of two fixed and movable contacts facing each other.

[0003] In addition to the three basic requirements of large current interruption performance, withstand voltage performance, and welding resistance performance, the vacuum circuit breaker has important requirements for contact resistance characteristics and temperature rise characteristics of the contacts.

[0004] However, since some of these requirements are contradictory, it is impossible to satisfy all the requirements with a single metal species. For this reason, in many contact materials that are in practical use, by combining two or more types of elements that complement each other for insufficient performance, it can be used for specific applications such as large current and high withstand voltage. Although the selection and adoption of contact materials suited to the requirements have been made, vacuum valves having excellent characteristics have been developed, but the fact is that a vacuum valve that sufficiently satisfies ever-increasing requirements has not yet been obtained.

[0005] For example, as a contact for the purpose of excellent large current interrupting property, C containing about 50% (% by weight) of Cr is used.
A u-Cr alloy (JP-B-45-35101) is known. This alloy realizes high voltage and large current disconnection by the action of Cr itself having substantially the same vapor pressure characteristics as Cu and exhibiting a strong gas getter action. That is, C
A u-Cr alloy is widely used as a contact capable of achieving both high withstand voltage characteristics and high capacity breaking.

Since this alloy uses highly active Cr, it is necessary to select a raw material powder when manufacturing a contact material (sintering step, etc.), or when processing a contact material into a contact piece. Although it is manufactured in consideration of contamination of impurities, management of atmosphere, etc., it is not necessarily a perfect technology for the supply of contact materials that have both the large current interruption characteristics and the contact resistance characteristics of vacuum valves. Absent.

[0007]

The contact surface of a CuCr contact has a relatively smooth surface damage characteristic even after disconnection, mainly because the vapor pressure characteristics at high temperatures are similar to each other. As a result, generally, stable contact resistance characteristics are exhibited. However, in recent years, it has become common practice to adapt to circuits where higher current interruption or higher voltage may be applied, and the contact surface has been noticeably worn and strongly welded. Instability of the contact resistance characteristics has been observed. In a vacuum valve, a contact that has been abnormally damaged or worn by shutting off may cause an abnormal increase in contact resistance or temperature when the next steady current is opened or closed,
In order to indicate a withstand voltage failure, it is necessary to suppress abnormal damage and wear of the contacts as much as possible.

According to research, the contact characteristics of a CuCr alloy include variations in the amount of Cr in the alloy, the particle size of Cr particles,
It turned out that it depends on the degree of r segregation, the degree of vacancies existing in the alloy, and the like. However, despite the progress of the optimization, the contact resistance characteristics vary in the recent adaptation situations described above, and this has an unfavorable effect on the cutoff characteristics. Therefore, a vacuum valve having both characteristics has become necessary.

An object of the present invention is to provide a vacuum circuit breaker having stable contact resistance characteristics and excellent large current breaking characteristics.

[0010]

In order to achieve the object of the present invention, the present invention according to the first aspect of the present invention is directed to a method for converting a particle diameter (in the case of an elliptical or polygonal particle into a circle having the same area as a circle). (Chromium) particles having a diameter of more than 40 μm and a Cu (copper) phase surrounding the particles.
And a second CuCr population formed of a plurality of Cr particles having a particle diameter smaller than 10 μm and a Cu phase surrounding the Cr particles, a part of the contact surface region is formed, A contact surface region is formed by a plurality of aggregates of a CuCr group and a second CuCr group, and the contact surface region forms part or all of a contact portion cross section. This is a vacuum circuit breaker equipped with Cr contacts.

That is, in general, in a vacuum circuit breaker, ordinary contacts are used in which the conditions of Cu and Cr in the contact surface area are not specially considered as in the above conditions. Vacuum circuit breakers are designed to shut off large currents and open and close small currents. The contact surface area that has been subjected to the arc is subjected to repeated melting, evaporation, and scattering, and the contact surface exhibits remarkable roughness and material consumption, resulting in a decrease in cutoff characteristics. The contact surface that undergoes such repetition of melting, evaporation, and scattering greatly changes its surface state each time it is interrupted, so in some cases, when it comes into contact so that a sufficient contact area can be secured, low contact occurs Although a resistance value is obtained, since the surface morphology changes every time interruption occurs, there is no guarantee that a sufficient contact will be obtained in the next interruption, and the contact resistance value will greatly change. As described above, when a large current is interrupted, the contact resistance characteristics vary greatly with the interruption.

However, according to the microscopic observation of the contact surface area when the number of interruptions is small (1 to several times), the shape,
In the Cr particles in the first CuCr group having a particle diameter larger than 40 μm, which is almost the same as the original shape of the raw material particles, and in the immediate vicinity thereof, there is little material damage and the phenomenon that arc resistance is exhibited. Admitted. On the other hand, if the particle diameter is 1
In the Cr particles in the second CuCr group smaller than the 0 μm class and very near the Cr particles, remarkable unevenness was observed, suggesting that the arc resistance was low.

When a small current is interrupted, a large arc is not received, so that there is little damage to the contact surface area, and there is no need for Cr particles larger than 40 μm for exhibiting arc resistance. From the point of view of importance, the uniformity of the structure becomes important, and the presence of Cr particles having a particle diameter smaller than the 10 μm class exerts its effect.

As described above, in the contact surface region where interruption of a large current and opening and closing of a small current are provided, a contact in which a plurality of the first CuCr group and the second CuCr group coexist is preferable.

According to a second aspect of the present invention, in the cross section of the contact portion, the thickness of the contact surface region formed by the first CuCr group and the second CuCr group is at least 20 μm from the outermost surface layer. The vacuum circuit breaker equipped with the Cu-Cr contact according to claim 1, wherein the vacuum circuit breaker has a depth.

That is, in general, in the case of a vacuum circuit breaker, the contact surface region that has received a large arc when a large current is interrupted is melted,
Evaporation may cause significant roughness and material consumption, and may cause a crater having a depth of about several μm to 10 μm from the contact surface. Therefore, in order to secure stable interruption characteristics and contact resistance characteristics, the thickness (depth) of the contact surface region formed by the first CuCr group and the second CuCr group is at least larger than the depth of the crater. It is necessary to have a depth of 20 μm.

According to a third aspect of the present invention, there is provided the first CuC
The vacuum circuit breaker having a Cu-Cr contact according to claim 1 or 2, wherein the size of the r group has a width of at least 200 µm and a length of at least 200 µm.

That is, in this vacuum circuit breaker, in order to stabilize the breaking characteristics and the contact resistance characteristics, it is necessary to reduce the range of variation in the values. In order to exhibit the breaking characteristics and the contact resistance characteristics without variation, it is important to reduce the variation in the structure.
r is preferably a plurality or more. However, the first C
When the width of the uCr group is substantially the same as the particle diameter of the raw material Cr, the number of Cr in the first CuCr group is, on average, at most 1 to several, and it is necessary to ensure arc resistance. This is not preferable for stabilizing the contact resistance. The same applies to the length.

According to a fourth aspect of the present invention, the second CuC
The vacuum circuit breaker having a Cu-Cr contact according to claim 1 or 2, wherein the size of the r group has a width of at least 200 µm and a length of at least 200 µm.

That is, in this vacuum circuit breaker, in order to stabilize the breaking characteristics and the contact resistance characteristics, it is necessary to reduce the range of variation in the values. It is important to reduce the variation in the structure in order to exhibit the blocking characteristics and the contact resistance characteristics without variation, and it is preferable that the second CuCr group also includes a plurality of Crs in the second CuCr population. However, when the width of the second CuCr group is substantially the same as the particle diameter of the raw material Cr, the number of Cr in the second CuCr group is, on average, at most one to several, and the resistance to Cr is limited. It is not preferable for securing the arc property and stabilizing the contact resistance. The same applies to the length.

According to a fifth aspect of the present invention, the total of the first CuCr group occupying the contact surface region is 20 to 80 area% [the first CuCr group / (the first CuCr group + the second CuCr group).
(CuCr group) = 0.2-0.8]. The vacuum circuit breaker equipped with the Cu-Cr contact according to claim 1, wherein:

That is, in this vacuum circuit breaker, a first CuCr population formed of Cr particles having a particle diameter larger than 40 μm and a Cu phase surrounding the particles,
The area ratio between the Cr particles smaller than μm and the second CuCr population formed of the Cu phase surrounding the particles has an important influence on the breaking performance and the stability of the contact resistance characteristics. In the case where the ratio of the first CuCr group in the contact surface region is less than 20 area% (the ratio of the second CuCr group is larger than 80 area%), the arc resistance is insufficient particularly when a large current is cut off. As a result, the cutoff characteristics are lowered, and the material of the contact surface area is severely damaged, and the contact resistance value fluctuates remarkably. When the ratio of the first CuCr group is greater than 80 area% (the ratio of the second CuCr group is less than 20 area%), the arc resistance is improved but the cutoff characteristics are reduced.

According to the present invention, the first CuC
The average Cr amount in the r group is 5 to 70% by weight, and the balance is Cu, The Cu-C according to claim 1, wherein the balance is Cu.
This is a vacuum circuit breaker equipped with an r contact.

That is, in this vacuum circuit breaker, the first C
When the amount of Cr in the uCr group is less than 5% by weight, the contact resistance value after opening / closing a small current shows stable characteristics, but in particular, the arc resistance when a large current is interrupted is not sufficient, so that the interruption characteristics deteriorate. Can be seen. When the amount of Cr in the first CuCr population is 7
If it exceeds 0% by weight, the arc resistance is improved, but the cutoff characteristics are reduced.

The present invention as set forth in claim 7 is characterized in that the second CuC
The average Cr amount in the r group is 10 to 80% by weight, and the balance is Cu.
This is a vacuum circuit breaker equipped with Cr contacts.

That is, in this vacuum circuit breaker, the second C
When the amount of Cr in the uCr group is less than 10% by weight, the contact resistance after opening / closing a small current exhibits stable characteristics, but the arc resistance when breaking a large current is not sufficient. Can be seen. The amount of Cr in the second CuCr population is
If it exceeds 80% by weight, the arc resistance is improved, but the cutoff characteristics are reduced.

[0027] The present invention according to claim 8 is characterized in that the first CuC
The chromium particles in the r group are obtained by converting a CuCr alloy
The vacuum having a Cu-Cr contact according to any one of claims 1 to 7, wherein the micro-Vickers hardness value Hv when reheated to 0 ° C and cooled to room temperature is 150 or more. It is a circuit breaker.

That is, in this vacuum circuit breaker, 750 ° C.
The Hv value at room temperature after re-ripening to ℃ 950 ° C. is Hv = 1.
If it is less than 50, the withstand voltage value is not sufficient, and the breaking performance is reduced. For stabilizing the restriking characteristic, preferably Hv =
Requires an Hv value of 200 or more.

According to the present invention, the first CuC
Cr particles surrounded by the Cu phase in the r group are 20 to 2
A vacuum circuit breaker having a Cu-Cr contact according to any one of claims 1 to 3, 5 to 6, and 8, wherein the vacuum circuit breaker has an average interparticle distance of 00 µm. .

That is, in this vacuum circuit breaker, the first C
If the gap between the Cr particles in the uCr population is smaller (narrower) than 20 μm, the variation in the contact resistance value is reduced, but the average contact resistance value is increased and the arc resistance is also reduced. If it is larger (wider) than 200 μm, the distribution of the contact resistance varies. 20-200μ
Providing an average interparticle distance of m is effective for stabilizing the arc resistance when breaking a large current and the contact resistance when switching a small current.

The present invention as set forth in claim 10 is characterized in that the second Cu
Cr particles surrounded by the Cu phase in the Cr population
8. A vacuum circuit breaker equipped with a Cu-Cr contact according to claim 1, wherein the vacuum circuit breaker has an average inter-particle distance of 1 to 20 [mu] m. It is.

That is, in this vacuum circuit breaker, CuCr
If the gap between the Cr particles in the group is smaller (narrower) than 0.01 μm, the production of the material cannot be performed economically.
If it is larger (wider) than 20 μm, the distribution of the contact resistance value varies.

[0033] The present invention as set forth in claim 11, wherein the first Cu
Part or all of Cr in at least one of the Cr group and the second CuCr group is replaced with 50% by weight or less of an X component (X = one of Ti, Ta, Nb, V, W, and Mo). A vacuum circuit breaker equipped with the Cu-Cr contact according to any one of claims 1 to 10.

That is, in this vacuum circuit breaker, the first C
The presence of the X component in at least one of the uCr group and the second CuCr group reduces the roughness of the contact surface region due to the improvement in arc resistance, stabilizes the contact resistance, and improves the withstand voltage characteristics. It is also beneficial for improvement.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

Even in the latest switchgear plants and switchgear systems, there are cases in which the breaking characteristics are varied or the function is not exhibited due to the quality defect of only one contact material having high performance. The present inventors have studied the contact materials used in the vacuum valve and compared them with the characteristics of the vacuum valve. As a result, the present invention has been completed. That is, the present invention has the following features.

In particular, when both the large current interruption and the small current switching are performed, the structure of the contact surface region and the structure in the cross-sectional direction (depth direction) of the contact surface region due to the passage of the number of interruptions or the number of switching operations. As a result, the breaking characteristics and the variation tended to decrease, and the contact resistance increased and the variation range increased. It was newly found that the material structure state was deeply involved.

[Sample] (Sample 1) having a particle diameter of 4
A Cu—Cr alloy having a texture distribution formed by a plurality of Cr particles of 0 μm or more (Cr particles of 40 μm or less exist at 5% by weight or less) and a Cu phase surrounding these particles was prepared [C
uCr population].

As (Sample 2), Cu—Cr having a texture distribution formed of a plurality of Cr particles having a particle diameter of 10 μm or less (Cr particles having a diameter of 10 μm or more is present at 5% by weight or less) and a Cu phase surrounding these particles. An alloy was prepared [CuCr group].

As (Sample 3), a CuCr group and Cu
A Cu—Cr alloy having a texture distribution in which both of the Cr populations were alternately and stereoscopically distributed on a microscopic scale was prepared [C
uCr population x].

In the case where the contact surface region is constituted only by the CuCr group, the arc resistance becomes bright when a large current of 20 kA class is cut off, but the contact resistance characteristic shows a large variation with a relatively small number of switching operations. In the case where the contact surface region was constituted only by the CuCr group, the arc resistance was not sufficient when a large current of 20 kA class was interrupted, and the interrupting characteristics showed a large variation at a relatively small number of interrupts.

In the case of a structure in which CuCr populations and CuCr populations are alternately distributed in a three-dimensional manner, compatibility between the cutoff characteristics and the contact resistance characteristics is maintained even after a relatively long number of interruptions or open / close times. CuCr group only or Cu
When only the Cr group is used, the compatibility between the cutoff characteristic and the contact resistance characteristic is broken in a relatively short period with respect to the elapse of the number of cutoffs or the number of times of opening and closing.

[Test] With respect to the CuCr contact pieces (samples 1 to 3) in each of these material structure states, (Test 1): a test for cutting off only a large current of 20 kA class, (Test 2): 30 A class (Test 3): A test combining the interruption of the large current and the opening and closing of the small current. (Test 3) is close to the actual field state.

[Summary of Result] When a large current of 20 kA class was cut off using the CuCr group of (Sample 1), excellent arc resistance was exhibited and contact wear was small. ), Which is superior to that of the present invention, but on the other hand, due to the presence of Cr particles having a large particle diameter,
A large variation is seen in the contact resistance value before opening and closing. Variations are also seen in the contact resistance values when switching small currents.

Therefore, a contact that forms a contact surface region only with the CuCr group of (Sample 1) is not preferable from the viewpoint of achieving both the breaking characteristic and the contact resistance characteristic.

Using the CuCr population of (Sample 2),
When a large current of 20 kA class is interrupted, the arc resistance at the time of interrupting the large current tends to be inferior to that of (Sample 1), the contact wear is large, and the current value is lower than that of (Sample 1). Uninterruptibility is caused, and the large-current interruption property is undesirably reduced. On the other hand, the contact resistance tends to increase as the number of cutoffs elapses, which is not preferable. The contact resistance before opening and closing shows stable contact resistance characteristics. After opening and closing (3
The contact resistance after opening / closing a small current of 0 A class exhibits stable breaking characteristics at a breaking current value of a certain fixed value or less, but the breaking characteristics suddenly decrease as the breaking current value increases. It has a tendency and is not preferred.

On the other hand, with respect to the contact resistance characteristics, when the cut-off current value is equal to or more than a certain fixed value or less, the surface damage shows a relatively small change even after the number of times of opening and closing, and shows stable contact resistance characteristics.

Therefore, a contact in which the contact surface region is formed only by the CuCr group of (Sample 2) is still not preferable from the viewpoint of achieving both the breaking characteristic and the contact resistance characteristic.

In the case where a large current of 20 kA class was cut off by using a structure in which the CuCr population and the CuCr population of (Sample 3) were alternately distributed, the existence of large Cr particles having a particle diameter of 40 μm or more was found to be resistant. As a result of exhibiting arc properties,
The contact surface has little damage and is effective in improving the breaking characteristics and ensuring stable contact resistance. In addition, when a small current of 30 A class is opened and closed, the presence effect of Cr particles of 10 μm or less makes the contact less scattered. This shows resistance characteristics.

Therefore, as described in (Sample 3), the CuC
a CuCr group in which a contact surface area is formed by allowing an r group and a CuCr group to exist at an appropriate ratio.
A contact is preferable for achieving both a breaking characteristic and a contact resistance characteristic.

As described above, in order to stabilize the characteristics of the CuCr contact, generally, the amount of Cr in the alloy and its fluctuation,
It depends on the particle size and the particle size distribution of Cr particles, the degree of segregation of Cr, the degree of vacancies in the alloy, etc. It has been found that, in addition to the above, the contact surface area formed by the mutual relationship between the Cr particles in the CuCr alloy and the Cu matrix is extremely important.

That is, in order to achieve both the shutoff characteristic and the contact resistance characteristic of the vacuum valve, the relationship between Cr and Cu in the alloy, that is, the presence of the above-mentioned CuCr group and the CuCr group in the contact surface area is determined by a predetermined ratio. It was found that it was essential to control

Hereinafter, embodiments of the present invention will be described in detail.
The evaluation conditions of the examples and comparative examples of the present invention are shown in FIGS. 1 to 3, and the evaluation results are shown in FIGS. 4 to 6.

The evaluation regarding the breaking characteristics and the contact resistance characteristics is as follows.
It went as follows. In some cases, the re-ignition characteristics and temperature rise characteristics were also evaluated as necessary. The contents of the test contact material and the manufacturing conditions are shown.

(1) Breaking Characteristics An experimental valve for a breaking test equipped with a contact having a diameter of 70 mm was attached to a switchgear, and after baking, voltage aging and the like were applied, the circuit was connected to a circuit of 24 kV and 50 Hz, and a current of approximately 1 kA was applied. The breaking limit was compared and evaluated for each of the three vacuum valves while gradually increasing. Numerical values are shown as relative values when the cutoff limit value in Example 2 was set to 1.0.

(2) Contact Resistance Characteristics A pure copper needle-like electrode having a radius of curvature of 50R is opposed to each plate-like contact piece with a contact load of 10 kg, and a potential drop between the two when a direct current of 10 A is applied is calculated from the following. Contact resistance was determined. The numerical value is based on the value of Example 2 and the contact resistance value is 0.75
(A), 0.75 or more to less than 1.5 times (B), and 1.5 or more to less than 3 times (C). On the other hand, the relative values are shown as (X) when the value is 3 times or more and less than 10 times less stable than the value of Example 2, (Y), and when it exceeds 30 times (Z). AC: good characteristics, X
To Z: poor characteristics).

(Reference) Temperature Rise Characteristics After assembling each contact piece into a vacuum valve, the temperature of the valve terminal was measured from the surface temperature in a non-contact manner using a high-sensitivity infrared thermometer. The value after subtracting was used as a temperature rise value.

(Reference) Re-ignition Characteristics Re-ignition occurs when a disc-shaped contact piece having a diameter of 30 mm and a thickness of 5 mm is mounted on a demountable vacuum valve and a circuit of 24 kV × 500 A is cut off 2,000 times. The frequency was measured and used as a reference. Note that the evaluation was performed when the re-ignition occurrence frequency was less than 0.1, which is lower than the value of Example 2, (A1), and 0.1 to 1
(A2) for the case of (B), (B), 1.5 for the case of 1 to 1.5
The case of ~ 3 was designated as (C). On the other hand, the case of 3 to 10 which occurred more frequently than in Example 2 was determined as (X), the case of 10 to 30 was determined as (Y), and the case of significantly larger was determined as (Z). X to Z: poor characteristics).

(3) Content of test Cr powder, content of CuCr alloy (Sample 1): A Cr powder having a particle diameter of 40 μm or more was obtained, for example, in a void of a Cr skeleton manufactured at 1150 ° C. in a vacuum. A CuCr alloy having a texture distribution formed by infiltrating separately prepared Cu to form a plurality of Cr particles having a particle diameter of 40 μm or more and a Cu phase surrounding these particles [C
uCr population a] was prepared.

Cu containing up to 40% by weight of Cr
In the case of producing a Cr alloy, 4
Cr powder having a particle diameter of 0 μm or more and C prepared separately
After mixing with u powder, solid phase sintering is performed at 1000 ° C.
A CuCr alloy [CuCr group b] having a texture distribution formed by a plurality of Cr particles having a particle diameter of 40 μm or more and a Cu phase surrounding them was prepared.

Further, an X component (X = Ti, Ta,
Cu-CrX containing one of Nb, V, W and Mo)
In the production of the alloy, in order to replace a part or all of Cr with an X component of 50% by weight or less, the X component is preliminarily mixed with the Cr powder to obtain a CrX mixed powder to obtain a CrX skeleton, and then a CuX skeleton. Or a mixture of CrX mixed powder and Cu powder to perform solid phase sintering, and a CuCrX having a texture distribution formed of compounded CrX particles having a particle diameter of 40 μm or more and a Cu phase surrounding them. An alloy [CuCr group c] was prepared.

(Sample 2): 10 μm by sieving method
A Cr powder having the following particle diameter was obtained (C of 10 μm or more).
r particles are mixed in an amount of 5% by weight or less).
Cu prepared separately is infiltrated into the voids of the Cr skeleton manufactured at 0 ° C., and the particle diameter is 10 μm or less (10 μm
A CuCr alloy [CuCr group a] having a texture distribution formed by a plurality of Cr particles (the above Cr particles are present at 5% by weight or less) and a Cu phase surrounding them is prepared.

Cu containing 10% by weight or more of Cr
In the case of manufacturing a Cr alloy, 1
Cr powder having a particle diameter of 0 μm or less and C prepared separately
After mixing with u powder, solid phase sintering is performed at 1000 ° C.
CuCr alloy having a texture distribution formed of a plurality of Cr particles having a particle diameter of 10 μm or less (Cr particles having a diameter of 10 μm or more are present in an amount of 5% by weight or less) and a Cu phase surrounding these particles [C
uCr population b] was prepared.

An X component (X = Ti, T
a, Nb, V, W, Mo)
In the production of the rX alloy, in order to replace a part or all of Cr with the X component of 50% by weight or less, the X component is preliminarily mixed with the Cr powder to obtain a CrX mixed powder to obtain a CrX skeleton. CuCrX having a texture distribution formed of a plurality of CrX particles having a particle diameter of 10 μm or less and a Cu phase surrounding the plurality of CrX particles having a particle diameter of 10 μm or less by infiltrating Cu or mixing a CrX mixed powder and a Cu powder. An alloy [CuCr group c] was prepared.

(Sample 3): Infiltration method (or solid phase sintering method)
After obtaining a low-density CuCr alloy (a state before complete sintering progresses) composed of the CuCr group produced in the above, this is powdered by a sieving method to obtain a CuCr alloy powder having a particle diameter of 40 μm or more. obtain.

A low-density (before complete sintering) CuCr alloy consisting of a group of CuCr similarly produced by the infiltration method (or solid-phase sintering method) is obtained, and then crushed and sieved. By the method, a CuCr alloy powder having a particle diameter of 10 μm or less is obtained.

The CuCr alloy powder obtained above and Cu
A Cr alloy powder is mixed with a Cr alloy powder at a predetermined ratio, and then this mixed powder is used as a raw material (after applying a pressing and molding operation if necessary) by an infiltration method (or a solid phase sintering method) to form a CuCr group and a CuCr group. A CuCr alloy [CuCr population x] having a texture distribution alternately and three-dimensionally distributed on a microscopic scale was prepared.

(4) Content of Test CuCr contact pieces (Sample 1) in each of these material structure states
(Test 1): A test to cut off only a large current of 20 kA class, (Test 2): A test to open and close only a small current of 30 A class, (Test 3): Cut off of the large current The test was a combination of small current switching and open / close testing. (Test 3) simulates the actual state of the field.

(5) Experimental valve for shut-off test An experimental valve for shut-off test was prepared by preparing a ceramic green container (main component: AL ₂ O ₃ ) polished to an average surface roughness of about 1.5 μm on the end face. Then, this ceramic insulating container was subjected to a preheating treatment at 1600 ° C. before assembling. 42% Ni-F with a plate thickness of 2 mm as a sealing metal
e alloy was prepared. As brazing material, 0.1mm thick 7
A 2% Ag-Cu alloy plate was prepared. The above prepared members are arranged between the objects to be joined (the end face of the insulating container made of ceramics and the sealing metal) so as to be able to be hermetically sealed and joined.
^-4 Pa. In a vacuum atmosphere, and subjected to a hermetically sealing process between the sealing fitting and the ceramic insulating container.

(Examples 1-4, Comparative Examples 1-2) 40 μm
Obtaining a Cr powder having the above particle diameter, for example, in a vacuum,
Microstructure distribution of Cu-Cr alloy formed by infiltrating separately prepared Cu into the voids of a Cr skeleton manufactured at 1150 ° C and including a plurality of Cr particles having a particle diameter of 40 µm or more and a Cu phase surrounding them. Is [CuCr group a].

A Cr powder having a particle diameter of 10 μm or less is obtained, and for example, a separately prepared Cu is infiltrated into a void of a Cr skeleton manufactured at 1150 ° C. in a vacuum to form a plurality of particles having a particle diameter of 10 μm or less. The texture distribution of the Cu—Cr alloy formed by the Cr particles and the Cu phase surrounding them is referred to as [CuCr group a].

Here, a Cu—Cr alloy having a structure distribution of only [CuCr group a] is referred to as Comparative Example-1 (Φ = 100 area%), and a Cu—Cr alloy having a structure distribution of only [CuCr group a] is used. Was set as Comparative Example-2 (Φ = 0 area%).

[CuCr group a] and [CuCr group a]
Of the [CuCr group a] in the group a], that is,

[0074]

(Equation 1)

However, Cu having a structure distribution of Φ = 80 area%
-Cr alloy, Cu-C having a structure distribution of Φ = 60 area%
Examples 1 to 4 were r alloys, Cu-Cr alloys having a structure distribution of Φ = 40 area%, and Cu-Cr alloys having a structure distribution of Φ = 20 area%. These samples were determined and selected by microscopic examination of the structure.

When only the large current of the 20 kA class was cut off (test 1), the cut-off current value of Example 2 was set to 1.0, and the cut-off current values of the respective samples were compared relatively. The result is shown in FIG. Example 2 when a large current interruption of 20 kA class is combined with a small current switching of 30 A class (test 3)
The breaking current value of each sample was set to 1.0, and the breaking current values of the respective samples were relatively compared. The result is shown in FIG. As for the contact resistance characteristics, in addition to the above (Test 1) and (Test 3), a test (Test 2) for opening and closing only a small current of 30A class was also performed.
The result is shown in FIG.

<Ratio Φ = 100, cut-off characteristics> Ratio Φ = 1
At the time of 00 (Comparative Example 1), in the breaking characteristic (Test 1) in which only a large current of 20 kA class was cut off, the breaking magnification was 1.25 to 1.3 times the breaking current value of Example 2 as a comparative standard. And has good blocking characteristics. Furthermore, even when a large current interruption of 20 kA class and a small current opening and closing of 30 A class are combined (test 3), the interruption magnification is 1.15 to 1.3 times and good interruption characteristics are obtained.

<Ratio Φ = 100, Contact Resistance Characteristics>
In the contact resistance characteristics after (Test 2), "B to C evaluation"
Is in the acceptable range. However, the contact resistance characteristics after (Test 1) indicate "X to Y evaluation" and the evaluation after (Test 3) indicates "Evaluation YZ", which is not preferable from the viewpoint of contact resistance. Compatibility is not obtained (Comparative Example 1).

<Ratio Φ = 0, cut-off characteristics> When the ratio Φ = 0 (Comparative Example 2), the cut-off characteristics in which only a large current of 20 kA class was cut off are the comparative standards in (Test 1). 0.75 to 1.0 times the breaking current value of the above, and a decrease in the breaking characteristics is seen. In (Test 3), the cutoff magnification was 0.4 to 0.7 times the cutoff current value of Example 2 as a comparative standard, and the cutoff characteristics were significantly reduced.

<Ratio Φ = 0, Contact Resistance Characteristics> On the other hand, the contact resistance characteristics after the (test 1) are in the rejected range in “X to Z evaluation”. The contact resistance characteristics after (Test 2) indicate “B to X evaluation”, and after (Test 3) indicate “Z evaluation”, which is not preferable in terms of contact resistance, and is preferable in both the breaking characteristics and the contact resistance characteristics. No (Comparative Example 2).

<Ratio Φ = 80 to 20, cutoff characteristics> Ratio Φ
= 80 to 20 (Examples 1 to 4), the cut-off characteristic (test 1) in which only a large current of 20 kA class was cut off was 1 to 1.25 times the cut-off current value of Example 2 as a comparative standard. And has good cut-off characteristics. In addition, 20k
Even in the case of combining the large current interruption of the class A and the small current switching of the 30A class (test 3), the interruption magnification is 0.9 to 1.25 times, and the circuit has good interruption characteristics.

<Ratio Φ = 80 to 20, contact resistance characteristics>
In the contact resistance characteristics after (Test 1), “B evaluation”
"B to C evaluation" is within the acceptable range. The contact resistance characteristics after (Test 2) are also acceptable in “B evaluation” and “A to B evaluation”. In the contact resistance characteristics after (Test 3), "B
Evaluation "and" B to C evaluation ", which are within the acceptable range. As described above, in the range of the ratio Φ = 80 to 20, both the cutoff characteristics and the contact resistance characteristics can be obtained (Examples 1 to 4).

(Examples 5 and 6, Comparative Example 3) Example 1 above
In Comparative Examples 1 and 2, when the thickness of the contact surface region (depth from the outermost surface layer) was fixed at 50 μm, the ratio of the CuCr group occupying the contact surface region was determined by the cutoff characteristics and the contact resistance characteristics. The effect on the coexistence was shown. However, in the technique of the present invention, the effect can be obtained without limiting the thickness of the contact surface region to 50 μm.

<Comparative Example 3> That is, when the thickness of the contact surface area is 10 μm (Comparative Example 3), the cutoff characteristic of cutting off only a large current of 20 kA class is set as a comparative standard in (Test 1). It becomes 0.6 to 1.0 times the cutoff current value of the second embodiment, and the cutoff characteristics are reduced. In (Test 3), the cut-off current value of Example 2 as a comparative standard was 0.5 to 1.0.
The cutoff magnification becomes twice, and the cutoff characteristics are significantly reduced.
In the contact resistance characteristics after (Test 2), "A to B evaluation"
, The contact resistance characteristics after (Test 1) indicate "C to X evaluation", and after (Test 3) indicate "Evaluation Z", and a large variation in the contact resistance value is observed. And it is not preferable, and it is not possible to obtain both the cutoff characteristic and the contact resistance characteristic (Comparative Example 3).

<Examples 5 to 6> On the other hand, when the thickness of the contact surface area is 20 to 350 μm (Examples 5 to 6), 20 k
In the breaking characteristic (test 1) in which only the large current of the class A was cut off, the breaking current value of the comparative example 2 was 0.9.
It exhibits a cutoff magnification of 5 to 1.1 times and has good cutoff characteristics.
Further, even when a large current interruption of 20 kA class and a small current opening and closing of 30 A class are combined (test 3), the interruption magnification is 0.9 to 1.1 times and good interruption characteristics are obtained.

In the contact resistance characteristics after (Test 1),
"B evaluation" is within the acceptable range. The contact resistance characteristics after (Test 2) are also in the acceptable range in “B evaluation”. The contact resistance characteristics after (test 3) also show "B evaluation", which is within the acceptable range.

As described above, the thickness of the contact surface area is 20 to 35.
Within the range of 0 μm, both the blocking characteristic and the contact resistance characteristic can be obtained.

(Examples 7 to 10 and Comparative Examples 4 to 5) In the above Examples 1 to 6 and Comparative Examples 1 to 3, the size (width and length of the group) of the CuCr group occupying the contact surface region was determined. , Width 2
00 μm, length 400 μm (hereinafter, width 200 / length 40
0) (abbreviated as 0), the effect on the compatibility between the breaking characteristic and the contact resistance characteristic is shown.

However, in the present invention, the size of the CuCr group (the width and the length of the group) occupying the contact surface area
Can obtain the effect without being limited to the width 200 / length 400.

<Comparative Example 4> That is, when the size of the CuCr group is width 200 / length 20 (Comparative Example 4), 20
In (Test 1), the cut-off characteristic of only the kA class large current was 0.55 to 1.1 times the cut-off current value of Example 2 as a comparative standard, and the cut-off characteristic was reduced.
In (Test 3), the breaking current is 0.5 to 1.0 times the breaking current value of Example 2 as a comparative standard, and the breaking characteristics are remarkably reduced.

In the contact resistance characteristics after (Test 2),
Although in the acceptable range in “A to B evaluation”, the contact resistance characteristics after (Test 1) showed a large variation from “B to Y evaluation”, and even after (Test 3), “B to Z evaluation” ", Which is not preferable in that a large variation is observed in the contact resistance value, and it is not possible to obtain both the breaking characteristic and the contact resistance characteristic.

<Examples 7 and 8> On the other hand, when the size (width and length of the group) of the CuCr group occupying the contact surface region is 200 / width 200/1000 (examples 7 and 8), In the cutoff characteristic (test 1) in which only a large current of 20 kA class was cut off, the cutoff magnification was 0.9 to 1.1 times the cutoff current value of Example 2 as a comparative standard, indicating good cutoff characteristics. Furthermore, even when a large current interruption of 20 kA class and a small current switching of 30 A class are combined (test 3), 0.9 to 1.
It shows a blocking magnification of 05 times and has good blocking characteristics.

In the contact resistance characteristics after (Test 1),
"B evaluation" is within the acceptable range. The contact resistance characteristics after (Test 2) are also in the acceptable range in “B evaluation”. The contact resistance characteristics after (Test 3) also show "B evaluation" and are in the acceptable range.

As described above, CuC occupying the contact surface region
When the size of the r group (width and length of the group) is in the range of width 200 / length 200 to 1000, both the blocking property and the contact resistance property can be obtained.

<Comparative Example 5> Similarly, when the size of the CuCr group is width 10 / length 400 (Comparative Example 5), 20 k
The interrupting characteristic that interrupts only the class A large current is (Test 1)
Here, 0.5 of the breaking current value of the second embodiment, which is a comparative standard, is used.
０．９0.9 times, and a decrease in cutoff characteristics is observed. In (Test 3), the breaking current is 0.3 to 0.8 times the breaking current value of Example 2 as a comparative standard, and the breaking characteristics are remarkably deteriorated and remarkably varied.

In the contact resistance characteristics after (Test 2),
Although "B to C evaluation" is within the acceptable range, the contact resistance characteristics after (Test 1) show a large variation from "C to Z evaluation", and "X to Z evaluation" even after (Test 3). And the contact resistance value shows a large increase and a large variation, which is not preferable, and it is not possible to obtain both the breaking characteristics and the contact resistance characteristics.

<Examples 9 to 10> On the other hand, the size of the CuCr group (the width and length of the group) occupying the contact surface area is
When the width is 400 to 1000 (Examples 9 to 10), 20
In the breaking characteristic (test 1) in which only a large current of the kA class was cut off, the breaking current value of the comparative example 2 of Example 2 was 1.1.
It exhibits a cutoff magnification of up to 1.3 times and has extremely good cutoff characteristics. Furthermore, even when a large current interruption of 20 kA class and a small current switching of 30 A class are combined (test 3), 1.0-1.2
It has a 5 times cutoff magnification and has very good cutoff characteristics.

The contact resistance characteristics after (Test 1) are
"B evaluation" is within the acceptable range. The contact resistance characteristics after (Test 2) are also in the acceptable range in “B evaluation”. The contact resistance characteristics after (Test 3) also show "C evaluation", and all are within the acceptable range.

As described above, CuC occupying the contact surface region
r The size of the group (the width and length of the group) is 200 to 1
In the range of 000/400, both the breaking characteristics and the contact resistance characteristics can be obtained.

Therefore, (Examples 7 to 8) and (Examples 9 to 8)
10) that the size of the CuCr population occupying the contact surface area is at least 200 μm wide and at least 2 μm.
It is preferable to satisfy the length of 00 μm.

(Examples 11 to 14 and Comparative Examples 6 and 7) In the above Examples 1 to 10 and Comparative Examples 1 to 5, the size (width and length of the group) of the CuCr group occupying the contact surface region was determined. Width 2
The effect of the size of the CuCr group (the width and length of the group) occupying the contact surface area on the balance between the breaking characteristics and the contact resistance characteristics when the ratio was fixed at 00 / length 400 was shown.

The technique of the present invention relates to the method of occupying Cu in the contact surface area.
The size of the Cr group (width and length of the group) is the width 2
The effect is obtained without being limited to 00 / length 400.

<Comparative Example 6> That is, when the size of the CuCr group (width and length of the group) occupying the contact surface area is 200 / width 20 (Comparative Example 6), only a large current of 20 kA class is obtained. The cut-off characteristic of Example 2 which is a comparative standard in (Test 1) is 0.35 to 0.5% of the cut-off current value of Example 2.
It is 55 times, which is not preferable because a remarkable decrease in the cutoff characteristic is observed. Also in (Test 3), the cutoff magnification is 0.2 to 0.65 times the cutoff current value of Example 2 which is a comparative standard, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
Although “B to C evaluation” is in the acceptable range, the contact resistance characteristics after (Test 1) show variations from “C to X evaluation”, and after (Test 3), “C to Z evaluation” And that the contact resistance value greatly varies,
It is not possible to achieve both the breaking characteristics and the contact resistance characteristics.

<Examples 11 to 12> On the other hand, the size of the CuCr group occupying the contact surface area (width and length of the group)
But width 200 / length 200 to 1000 (Examples 11 to 1)
In the case of 2), the breaking characteristic (test 1) in which only a large current of 20 kA class was cut off showed a breaking magnification of 1.05 to 1.1 times the breaking current value of Example 2 as a comparative standard, showing good breaking. Has characteristics.

Further, even when a large current interruption of 20 kA class and a small current switching of 30 A class are combined (test 3), 0.9 is obtained.
It shows a cutoff magnification of up to 1.05 times and has good cutoff characteristics.

In the contact resistance characteristics after (Test 1),
"B evaluation" is within the acceptable range. The contact resistance characteristics after (Test 2) are also in the acceptable range in “B evaluation”. The contact resistance characteristics after (Test 3) also show "B evaluation" and are in the acceptable range.

As described above, CuC occupying the contact surface region
When the size of the r group (width and length of the group) is in the range of width 200 / length 200 to 1000, both the blocking property and the contact resistance property can be obtained.

<Comparative Example 7> When the size of the CuCr group is width 10 / length 400 (Comparative Example 7), the cutoff characteristic of blocking only a large current of 20 kA class is set as a comparative standard in (Test 1). 0.8 to 0.9 of the breaking current value of Example 2
It becomes twice as large and the cutoff characteristics are reduced. In (Test 3), the breaking current of 0.25 to
The cutoff magnification is 0.5 times, and the cutoff characteristics are remarkably deteriorated and remarkably varied.

In the contact resistance characteristics after (Test 2),
Although in the acceptable range in “B to C evaluation”, the contact resistance characteristics after (Test 1) showed a large variation from “B to X evaluation”, and even after (Test 3), the “C to X evaluation” ", Which is not preferable in that a large increase and a large variation are seen in the contact resistance value, and it is not possible to obtain both the breaking characteristics and the contact resistance characteristics.

<Examples 13 and 14> On the other hand, the size of the CuCr group occupying the contact surface region (width and length of the group)
However, when the width is 400 to 1000 (Examples 13 and 14), the breaking characteristic (Test 1) in which only a large current of 20 kA class is cut off is 1.1 to 1 of the breaking current value of Example 2 as a comparative standard. It has a cut-off magnification of 15 times and has very good cut-off characteristics. Furthermore, large current interruption of 20kA class and 30A
Even with the combination of small current switching of the class (Test 3), even the combination
It exhibits a cutoff magnification of 95 to 1.15 times and has extremely good cutoff characteristics.

In the contact resistance characteristics after (Test 1),
"B evaluation" is within the acceptable range. The contact resistance characteristics after (Test 2) are also in the acceptable range in “B evaluation”. The contact resistance characteristics after (Test 3) also show "B evaluation" and are all within the acceptable range.

As described above, CuC occupying the contact surface region
r The size of the group (the width and length of the group) is 200 to 1
In the range of 000/400, both the breaking characteristics and the contact resistance characteristics can be obtained.

Therefore, according to (Examples 11 to 12) and (Examples 13 to 14), the size of the CuCr group occupying the contact surface region must satisfy at least the width of 200 μm and the length of at least 200 μm. (Example 1
1-14).

(Examples 15 to 17, Comparative Examples 8 to 9) In Examples 1 to 14 and Comparative Examples 1 to 7, the breaking characteristics and the contact resistance when the average Cr content in the CuCr population was 25% by weight. The effects on the compatibility of characteristics were shown.

The technique of the present invention is based on the average C in the CuCr population.
The effect is obtained without limiting the amount of r to 25% Cr.

<Comparative Example 8> That is, when the average Cr content in the CuCr group was 2% by weight, the cutoff characteristic of cutting off only a large current of 20 kA class was the same as that of Example 2 which was used as a comparative standard in (Test 1). 0.75 to 1.05 of the breaking current value
This is unfavorable because the variation in cutoff characteristics is seen.
(Test 3) also shows a cutoff magnification of 0.5 to 0.8 times the cutoff current value of the comparative example 2 of Example 2, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
It shows "A evaluation" and is in the pass range, and the contact resistance characteristic after (Test 1) also shows "AB" and is in the pass range, and shows "B evaluation" even after (Test 3). I do. Although the contact resistance characteristic is in the acceptable range, it is not preferable from the viewpoint of compatibility between the cutoff characteristic and the contact resistance characteristic.

<Comparative Example 9> Average Cr in CuCr population
When the amount is 90% by weight, the breaking characteristic of blocking only a large current of 20 kA class is 0.5 to 0.65 times the breaking current value of Example 2 which is a comparative standard in (Test 1). A significant decrease is observed, which is not preferable. Also in (Test 3), the cutoff magnification is 0.4 to 0.6 times the cutoff current value of Example 2 which is a comparative standard, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
"C to Z evaluation" shows a significant decrease and variation. The contact resistance characteristic after (Test 1) also shows a large variation with "X to Z evaluation", and the contact resistance value shows a large increase after (Test 3) with "Y to Z evaluation". Undesirable
Both the cutoff characteristics and the contact resistance characteristics show a decrease in characteristics. It is not preferable from the viewpoint of compatibility between the breaking characteristics and the contact resistance characteristics.

<Examples 15 to 17> When the average amount of Cr in the CuCr group was 5 to 70% by weight (Examples 15 to 17), the cutoff characteristic of cutting off only a large current of 20 kA class was as follows.
In (test 1), the cut-off current value is 0.95 to 1.3 times the cut-off current value of the comparative example 2 and exhibits excellent cut-off characteristics. Example 2 used as a comparative standard in (Test 3)
Of 0.9 to 1.2 times the breaking current value of the above, and exhibits excellent breaking characteristics.

In the contact resistance characteristics after (Test 2),
"AB evaluation", "B evaluation", "BC evaluation" are in the acceptable range, and the contact resistance characteristics after (test 1) also show "B evaluation", "BC evaluation" In the pass range,
Even after (Test 3), "B evaluation", "BC evaluation",
Demonstrate "C evaluation".

Therefore, from (Examples 15 to 17), Cu
When the average amount of Cr in the Cr group is set to 5% by weight to 70% by weight, both of the blocking characteristic and the contact resistance characteristic can be obtained.

(Examples 18 to 20, Comparative Examples 10 to 11)
In the above Examples 1 to 17 and Comparative Examples 1 to 9, the effects on the compatibility between the cutoff characteristics and the contact resistance characteristics when the average Cr amount in the CuCr group was 25% by weight were shown.

The technique of the present invention is based on the average C in the CuCr population.
The effect is obtained without limiting the amount of r to 25% Cr.

<Comparative Example 10> That is, when the average amount of Cr in the CuCr group was 5% by weight, the cut-off characteristic of cutting off only a large current of 20 kA class was the same as that of Example 2 which was used as a comparative standard in (Test 1). 0.8 to 0.95 of the breaking current value
This is unfavorable because the cutoff characteristics are reduced. (Test 3) also shows a cutoff magnification of 0.6 to 0.8 times the cutoff current value of Example 2 which is a comparative standard, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
It shows "A evaluation" and is in the pass range, and the contact resistance characteristic after (Test 1) also shows "AB" and is in the pass range, and shows "B evaluation" even after (Test 3). I do. Although the contact resistance characteristic is in the acceptable range, it is not preferable from the viewpoint of compatibility between the cutoff characteristic and the contact resistance characteristic.

<Comparative Example 11> Average C in CuCr population
When the amount of r is 90% by weight, the breaking characteristic of blocking only a large current of 20 kA class is 0.6 to 0.7 times the breaking current value of Example 2 which is a comparative standard in (Test 1). Is unfavorably observed. (Test 3) The cut-off current value of Example 2 which is also a comparative standard is 0.4 to
The cutoff magnification is 0.6 times, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
"C to Z evaluation" shows a significant decrease and variation. The contact resistance characteristic after (Test 1) also shows a large variation with "X to Z evaluation", and the contact resistance value shows a large increase after (Test 3) with "Y to Z evaluation". Undesirable
Both the cutoff characteristics and the contact resistance characteristics show a decrease in characteristics. It is not preferable from the viewpoint of compatibility between the breaking characteristics and the contact resistance characteristics.

<Examples 18 to 20> When the average amount of Cr in the CuCr group was 10 to 80% by weight (Examples 18 to 20), the cut-off characteristic of cutting off only a large current of 20 kA class was (Test 1). In this case, the breaking current value is 1.0 to 1.15 times the breaking current value of Example 2 which is a comparative standard, and excellent breaking characteristics are exhibited. (Test 3) also exhibits a breaking magnification of 0.9 to 1.0 times the breaking current value of Example 2 which is a comparative standard, and exhibits excellent breaking characteristics.

In the contact resistance characteristics after (Test 2),
"AB evaluation", "B evaluation", "BC evaluation" are in the acceptable range, and the contact resistance characteristics after (test 1) also show "B evaluation", "BC evaluation" In the pass range,
Even after (Test 3), "B evaluation", "BC evaluation",
Demonstrate "C evaluation".

Therefore, from (Examples 18 to 20), Cu
When the average amount of Cr in the Cr group is set to 10% by weight to 80% by weight, both the blocking property and the contact resistance property can be obtained.

(Examples 21 to 22, Comparative Examples 12 to 13)
In the above Examples 1 to 20 and Comparative Examples 1 to 11, the effects on the compatibility between the breaking characteristics and the contact resistance characteristics when the Cr content in the whole CuCr alloy was 25% by weight were shown.

The technology of the present invention relates to the method of
The amount is not limited to the above-mentioned 25% Cr, and an effect can be obtained.

<Comparative Example 12> That is, when the amount of Cr in the entire CuCr alloy was 2% by weight, the cut-off characteristic of cutting off only a large current of 20 kA class was the same as that of Example 2 which was used as a comparative standard in (Test 1) It is 0.65 to 1.0 times the breaking current value, and the variation in the breaking characteristics is unfavorably observed. Also in (test 3), the cutoff magnification is 0.25 to 0.65 times the cutoff current value of the comparative example 2 of Example 2, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
It shows "A evaluation" and is in the pass range, and the contact resistance characteristic after (Test 1) also shows "AB" and is in the pass range, and shows "B evaluation" even after (Test 3). I do. Although the contact resistance characteristic is in the acceptable range, it is not preferable from the viewpoint of compatibility between the cutoff characteristic and the contact resistance characteristic.

<Comparative Example 13> Cr in the whole CuCr alloy
When the amount is 90% by weight, the breaking characteristic of blocking only a large current of 20 kA class is 0.55 to 0.7 times the breaking current value of Example 2 which is a comparative standard in (Test 1). A significant decrease is observed, which is not preferable. (Test 3) also shows a breaking magnification of 0.4 to 0.55 times the breaking current value of Example 2 which is a comparative standard, and the breaking characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
"C to Z evaluation" shows a significant decrease and variation. The contact resistance characteristic after (Test 1) also shows a large variation with "X to Z evaluation", and the contact resistance value shows a large increase after (Test 3) with "Y to Z evaluation". Undesirable
Both the cutoff characteristics and the contact resistance characteristics show a decrease in characteristics. It is not preferable from the viewpoint of compatibility between the breaking characteristics and the contact resistance characteristics.

<Examples 21 to 22> When the amount of Cr in the entire CuCr alloy was 5 to 70% by weight (Examples 21 to 22), the breaking characteristics of blocking only a large current of 20 kA class were as follows.
In (test 1), the cutoff current value is 1.0 to 1.2 times the cutoff current value of the comparative example 2 and exhibits excellent cutoff characteristics. Also in (test 3), the cutoff current value is 0.9 to 1.1 times the cutoff current value of Example 2 which is a comparative standard, and excellent cutoff characteristics are exhibited.

In the contact resistance characteristics after (Test 2),
It shows "AB evaluation" and "BC evaluation" and is in the acceptable range, and the contact resistance characteristics after (test 1) are also "B evaluation".
It shows "B to C evaluation" and is in the acceptable range (Test 3)
After that, "B evaluation" and "C evaluation" are exhibited.

Therefore, from (Examples 21 to 22), Cu
When the amount of Cr in the entire Cr alloy is set to 5% by weight to 70% by weight, both the blocking property and the contact resistance property can be obtained.

(Examples 23 to 25, Comparative Examples 14 to 15)
In the above Examples 1 to 22 and Comparative Examples 1 to 13, the influence on the compatibility between the blocking characteristics and the contact resistance characteristics when the average distance between Cr particles in the CuCr group was fixed at 35 µm was shown.

The technique of the present invention is effective without limiting the average intergranular distance of Cr in the CuCr population to 35 μm.

<Comparative Example 14> That is, when the average interparticle distance of Cr in the CuCr population was 5 μm, 20 kA
The breaking characteristic of blocking only large current of the class was 0.9 to 0.9 of the breaking current value of Example 2 which is a comparative standard in (Test 1).
Although it was within the acceptable range of 1.05 times, (Test 3) was 0.45 of the cut-off current value of Example 2 as a comparative standard.
The cutoff magnification becomes about 0.65 times, and the cutoff characteristics are reduced.

In the contact resistance characteristics after (Test 2),
It shows "B evaluation" and is in a pass range, and the contact resistance characteristic after (Test 1) also shows "B evaluation" and is in a pass range.
Even after (Test 3), "C evaluation" is exhibited. Although the contact resistance characteristic is in the acceptable range, it is not preferable from the viewpoint of compatibility between the cutoff characteristic and the contact resistance characteristic.

<Comparative Example 15> When the average interparticle distance of Cr in the CuCr group was 500 μm, the cutoff characteristic of cutting off only a large current of 20 kA class was the same as that of Example 2 which was used as a comparative standard in (Test 1). 0.65-0.
It is 95 times, which is not preferable because the cutoff characteristics are reduced.
(Test 3) also shows a breaking magnification of 0.3 to 1.2 times the breaking current value of Example 2 which is a comparative standard, and further lowers the breaking characteristics.

In the contact resistance characteristics after (Test 2),
"B to X evaluation" and variations are shown. The contact resistance characteristics after (Test 1) also show large variations in "B to Y evaluation", and even after (Test 3), the contact resistance values show large variations in "B to Z evaluation", which is not preferable. Both the cutoff characteristics and the contact resistance characteristics show a decrease in characteristics. It is not preferable from the viewpoint of compatibility between the breaking characteristics and the contact resistance characteristics.

<Examples 23 to 25> The average interparticle distance of Cr in the CuCr population was 20 to 200 µm (Example 23 to 25).
In the case of (1) to (25), the cut-off characteristic in which only a large current of 20 kA class was cut off was 0.95 to 1.15 times the cut-off current value of Example 2 which is a comparative standard in (Test 1). Demonstrate. Also in (test 3), the cutoff current value is 0.9 to 1.1 times the cutoff current value of Example 2 which is a comparative standard, and excellent cutoff characteristics are exhibited.

In the contact resistance characteristics after (Test 2),
"A", "AB evaluation", "BC evaluation" are in the acceptable range, and the contact resistance characteristics after (test 1) are also "A ~"
B evaluation "," B ~ C evaluation "and in the range of passing,
Even after (Test 3), "B evaluation", "AB evaluation",
Demonstrates “B to C evaluation”.

Therefore, from Examples 23 to 25, Cu
The average distance between Cr particles in the Cr population is 20 to 200 μm.
When it is set to m, both the breaking characteristic and the contact resistance characteristic can be obtained.

(Examples 26 to 29, Comparative Examples 16 to 17)
In the above Examples 1 to 25 and Comparative Examples 1 to 15, the effects on the compatibility between the cutoff characteristics and the contact resistance characteristics when the average distance between the Cr particles in the CuCr population was fixed at 0.5 μm were shown.

The technique of the present invention is effective without limiting the average intergranular distance of Cr in the CuCr population to 0.5 μm.

<Comparative Example 16> Making the average intergranular distance of Cr less than 0.01 μm in the CuCr population would not make the production of the material economical, so the trial production was stopped.

<Comparative Example 17> When the average interparticle distance of Cr in the CuCr population was 30 μm, the cutoff characteristic of cutting off only a large current of 20 kA class was the same as that of Example 2 which was used as a comparative standard in (Test 1). 0.55-0.8 of current value
It is five times, and the blocking characteristics are deteriorated, which is not preferable. Also in (Test 3), the cutoff magnification is 0.4 to 0.95 times the cutoff current value of Example 2 as a comparative standard, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
Although in the acceptable range of “B to C evaluation”, the contact resistance characteristics after (Test 1) showed a large variation from “B to X evaluation”, and even after (Test 3), the “C to Y evaluation” And the contact resistance value greatly varies, which is not preferable, and both the cutoff characteristics and the contact resistance characteristics show a decrease in the characteristics. It is not preferable from the viewpoint of compatibility between the breaking characteristics and the contact resistance characteristics.

<Examples 26 to 29> The average interparticle distance of Cr in the CuCr population was 0.01 to 20 µm (Example 2 to 29).
In the case of 6 to 29), the breaking characteristic in which only a large current of 20 kA class was cut was 0.95 to 1.2 times the breaking current value of Example 2 which is a comparative standard in (Test 1), and excellent breaking was achieved. Demonstrate the characteristics. Also in (test 3), the cutoff current value is 0.9 to 1.1 times the cutoff current value of Example 2 which is a comparative standard, and excellent cutoff characteristics are exhibited.

In the contact resistance characteristics after (Test 2),
"AB evaluation", "B evaluation" is in the range of passing,
The contact resistance characteristics after (Test 1) also show "B to C evaluation" and are in the acceptable range, and also exhibit "B evaluation", "B to C evaluation", and "C evaluation" even after (Test 3). I do.

Therefore, from Examples 26 to 29, Cu
The average interparticle distance of Cr in the Cr population is 0.01 to 20.
When the thickness is set to μm, both the blocking characteristic and the contact resistance characteristic can be obtained.

(Examples 30 to 32, Comparative Example 18) In Examples 1 to 29 and Comparative Examples 1 to 17, the CuCr alloy was
Influence on reconciliation of the interception characteristics and the contact resistance characteristics when the micro Vickers hardness value Hv of the Cr particles in the CuCr population is 200 when reheated to 50 to 950 ° C. and then cooled to room temperature. Indicated.

The present invention relates to a CuCr alloy of 750 to 9
After reheating to 50 ° C. and cooling to room temperature, Cu
Micro-Vickers hardness value H of Cr particles in Cr population
The effect is obtained without limiting v to 200.

<Comparative Example 18> CuCr alloy was added to 750-9
After reheating to 50 ° C. and cooling to room temperature, Cu
Micro-Vickers hardness value H of Cr particles in Cr population
When v is set to 120, the cut-off characteristic in which only a large current of 20 kA class is cut off is 0.45 to 0.7 times the cut-off current value of Example 2 which is a comparative standard in (Test 1), and the cut-off characteristic is lowered. Are not preferred. (Test 3) 0.3 to less than the breaking current value of Example 2 which is also a comparative standard.
The cutoff magnification is 0.5 times, and the cutoff characteristics are further reduced.

In the contact resistance characteristics after (Test 2),
The contact resistance characteristics after (test 1) are in the acceptable range, indicating "A evaluation", and are also in the acceptable range after "test 3". Demonstrate.
Although the contact resistance characteristic is in the acceptable range, it is not preferable from the viewpoint of compatibility between the cutoff characteristic and the contact resistance characteristic.

<Embodiments 30 to 32> The CuCr alloy is
When the micro-Vickers hardness value Hv of the Cr particles in the CuCr population at the time of reheating to 0 to 950 ° C. and then cooling to room temperature is 150 to 280 (Examples 30 to 32), a large value of 20 kA class is obtained. The cut-off characteristic in which only the current was cut off is 0.95 to 1.2 times the cut-off current value of Example 2 which is a comparative standard in (Test 1), and exhibits excellent cut-off characteristics. (Test 3) also exhibits a breaking magnification of 0.9 to 1.05 times the breaking current value of Example 2 as a comparative standard, and exhibits excellent breaking characteristics.

In the contact resistance characteristics after (Test 2),
"AB evaluation", "B evaluation" is in the range of passing,
The contact resistance characteristics after (Test 1) were also “B evaluation”, “B ~
"C evaluation" is within the acceptable range, and "B evaluation" and "BC evaluation" are exhibited even after (Test 3).

Therefore, from (Examples 30 to 32), Cu
When the Cr alloy is reheated to 750 to 950 ° C. and then cooled to room temperature, when the micro-Vickers hardness value Hv of the Cr particles in the CuCr population is set to 150 or more, both the blocking property and the contact resistance property are satisfied. Is obtained. In order to stabilize the re-ignition characteristic, it is preferable that an Hv value of Hv = 200 or more is required.

(Modification) The above-mentioned CuCr group and CuC
and 50% by weight or less of the X component (X = Ti, Ta, N
b, V, W, or Mo).

The presence of the X component in the CuCr group or in the CuCr group reduces the roughness of the contact surface region due to the improvement in arc resistance, stabilizes the contact resistance, and is useful for improving the withstand voltage characteristics. Becomes

[0168]

As described above, according to the present invention,
A vacuum circuit breaker having stable contact resistance characteristics and excellent large current breaking characteristics can be realized.

[Brief description of the drawings]

FIG. 1 shows Examples 1 to 14 of the present invention and Comparative Examples 1 to 7.
FIG. 2 is a table showing evaluation conditions.

FIG. 2 shows Examples 15 to 25 of the present invention and Comparative Examples 8 to
FIG. 15 is a table showing 15 evaluation conditions.

FIG. 3 shows Examples 26 to 32 of the present invention and Comparative Example 16
FIG. 19 is a table showing evaluation conditions of Nos. To 18;

FIG. 4 shows Examples 1 to 14 of the present invention and Comparative Examples 1 to 7.
FIG. 4 is a table showing evaluation results of the above.

FIG. 5 Examples 15 to 25 of the present invention and Comparative Examples 8 to
15 is a table showing the evaluation results of 15; FIG.

FIG. 6 shows Examples 26 to 32 of the present invention and Comparative Example 16
FIG. 19 is a table showing evaluation results of Nos. To 18.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Kusano 1 Toshiba-cho, Fuchu-shi, Tokyo Tokyo, Japan Inside the Fuchu office of Toshiba Corporation (72) Inventor Mitaka Honma 1-futoshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu office, Toshiba ( 72) Inventor Iwao Oshima 1 Toshiba-cho, Fuchu-shi, Tokyo, Japan Inside the Fuchu Office, Toshiba Corporation (72) Inventor Atsushi Yamamoto 1-toshiba, Toshiba-cho, Fuchu-shi, Tokyo Inside Fuchu Office, Toshiba Corporation (72) Inventor Keisei Seki Tokyo 1 Toshiba-cho, Fuchu-shi F-term in Toshiba Corporation Fuchu Plant (reference)

Claims (11)

[Claims] A plurality of Cr particles having a particle diameter of more than 40 μm.
The first C formed by the particles and the surrounding Cu phase
uCr population and multiple C particles with particle diameters smaller than 10 μm
r particles and a second CuCr group formed of a Cu phase surrounding the r particles form a part of the contact surface region; and a plurality of the first CuCr group and the second CuCr group. A vacuum circuit breaker equipped with a Cu-Cr contact, wherein a contact surface region is formed by an aggregate of the above, and the contact surface region constitutes a part or all of a cross section of the contact portion. 2. The method according to claim 2, wherein the first Cu
The Cu-Cr according to claim 1, wherein the thickness of the contact surface region formed by the Cr group and the second CuCr group has a depth of at least 20 µm from the outermost layer.
Vacuum circuit breaker with contacts. 3. A Cu-Cr contact according to claim 1, wherein the size of the first CuCr population has a width of at least 200 μm and a length of at least 200 μm. Vacuum circuit breaker. 4. A Cu-Cr contact according to claim 1, wherein the size of the second CuCr population has a width of at least 200 μm and a length of at least 200 μm. Vacuum circuit breaker. 5. The first Cu occupying the contact surface area.
The vacuum circuit breaker having a Cu-Cr contact according to claim 1, wherein the total of the Cr group has a ratio of 20 to 80 area%. 6. The vacuum interrupter according to claim 1, wherein the average amount of Cr in the first CuCr group is 5 to 70% by weight, and the balance is Cu. vessel. 7. The vacuum interrupter according to claim 1, wherein the average amount of Cr in the second CuCr group is 10 to 80% by weight, and the balance is Cu. vessel. 8. The Cr particles in the first CuCr population,
When the CuCr alloy is reheated to 750 to 950 ° C. and cooled to room temperature, the micro Vickers hardness value Hv is 150
The vacuum circuit breaker equipped with the Cu-Cr contact according to any one of claims 1 to 7, characterized in that: 9. The Cr particles surrounded by the Cu phase in the first CuCr population have an average interparticle distance of 20 to 200 μm. The Cu- according to any one of claims 6 and 8,
Vacuum circuit breaker with Cr contacts. 10. The method according to claim 1, wherein the Cr particles surrounded by the Cu phase in the second CuCr population have an average interparticle distance of 0.01 to 20 μm.
C according to any one of claims 4 to 5, and 7
Vacuum circuit breaker with u-Cr contacts. 11. An X component (X = Ti, T) of 50% by weight or less of a part or all of Cr in at least one of the first CuCr group and the second CuCr group.
11. Cu according to any one of claims 1 to 10, characterized by being substituted by one of a, Nb, V, W and Mo).
-Vacuum circuit breaker with Cr contacts.