JPH0779013B2

JPH0779013B2 - Contact material for vacuum valve

Info

Publication number: JPH0779013B2
Application number: JP24446887A
Authority: JP
Inventors: 功奥富; 薫旦関口; 経世関
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 1987-09-29
Filing date: 1987-09-29
Publication date: 1995-08-23
Anticipated expiration: 2010-08-23
Also published as: JPS6486424A

Description

[Brief description of drawings]

第１図は、本発明の接点材料が適用される真空しゃ断器
の断面図であり、第２図は、接点部の拡大断面図であ
る。１……しゃ断室、２……絶縁容器、3a,3b……封止金
具、4a,4b……蓋体、5,6……導電棒、７……電極（固定
電極）、８……電極（可動電極）、９……ベローズ、1
0,11……アークシールド、12……ロウづけ部、13a,13b
……接点、14……取付け部。FIG. 1 is a sectional view of a vacuum breaker to which the contact material of the present invention is applied, and FIG. 2 is an enlarged sectional view of a contact portion. 1 ... Shut-off chamber, 2 ... Insulation container, 3a, 3b ... Sealing metal fittings, 4a, 4b ... Lid, 5,6 ... Conductive rod, 7 ... Electrode (fixed electrode), 8 ... Electrode (Movable electrode), 9 ... Bellows, 1
0,11 …… Arc shield, 12 …… Brazed part, 13a, 13b
...... Contact point, 14 …… Mounting part.

Claims

[Claims]

1. A Cr having an average particle size in the range of 44 to 250 μm.
(B) Highly conductive material consisting of (b) Cu or / and Ag, and (c) a low solid solubility with respect to the arc resistant material consisting of Cr, and having the same or lower level as the arc resistant material. A contact material for a vacuum valve, which is formed of an auxiliary material having a vapor pressure and an average particle diameter smaller than that of the arc-resistant material.

2. The (c) auxiliary material is Mo, W, Ti and
A metal carbide or boride selected from the group consisting of Cr, and having a particle size in the range of 0.5 to 10 μm,
The contact material according to claim 1.

3. The volume A of the arc resistant material composed of (a) Cr.
And the ratio (c) of the auxiliary material (C) is And the total of (a) + (c) occupies 20 to 80% by volume in the total material, and the balance is made of a conductive material composed of Cu or / and Ag. The contact material for a vacuum valve according to item 1 or 2.

4. The ratio D / B between the average particle diameter D of the auxiliary material and the average particle diameter B of the arc-resistant material made of Cr in the alloy is 0.2 or less. The contact material for a vacuum valve according to any one of 3 above.

5. The ratio of Cu and Ag is almost eutectic composition (Ag: Cu
≈7: 3), which is defined in claims 1 to 4
The contact material for a vacuum valve according to any one of claims. Of the invention
DETAILED DESCRIPTION [Object of the Invention] (Industrial field of application) The present invention relates to a vacuum valve, and in particular to an improved welding resistance property.
Contact material for vacuum valves. (Prior art) The characteristics required for contact materials for vacuum valves are:
Three basics that are indicated by each performance against wear, withstand voltage and cutoff
And other factors such as temperature rise and contact resistance are low and stable.
It is important that the tripping current value is low and stable.
It is a matter. However, some of these requirements
Because there are conflicting things, all can be done with a single metal species.
It is impossible to satisfy the requirement of. For this reason,
Insufficient performance for many used contact materials
A combination of two or more elements that complement each other and
Suitable for specific applications such as current or high voltage
Contact materials have been developed, and they have excellent characteristics
Some products have been developed, but have higher withstand voltage
And contacts for vacuum valves that fully meet the requirements for high current
The reality is that the material has not yet been obtained. For example, Bi is used as a contact material for high current.
Cu-Bi alloy containing 5% or less
It is known (Japanese Patent Publication No. 41-12131), but it is not suitable for Cu matrix.
Bi has a very low solubility and often causes segregation.
Surface roughening after cutting and cutting, making processing and molding difficult
There are problems such as In addition, as another contact material aimed at increasing the current, Cu-Te
Alloys are also known (Japanese Patent Publication No. 44-23751). This case
Gold alleviates the above problems of Cu-Bi alloys
However, it is more sensitive to the atmosphere than Cu-Bi alloys.
Therefore, it lacks stability such as contact resistance. Furthermore, these Cu-
As a common feature of contacts such as Te and Cu-Bi, it has excellent welding resistance.
However, the withstand voltage characteristics are
Even if it is sufficient for application, it will be applied to higher voltage fields.
Clearly not always satisfactory for the application of
It's coming. On the other hand, a Cu-Cr alloy containing Cr is a contact material for vacuum circuit breakers.
Known as a fee. This contact alloy is
High resistance as the thermal properties of Cr and Cu are exhibited in a favorable state
It has excellent characteristics for high pressure current. Sanawa
The Cu-Cr alloy has both high withstand voltage characteristics and large capacity interruption.
It is often used as a contact point. However, Cu
-Cr alloy is commonly used as a contact material for circuit breakers.
Compared with the Cu-Bi contact in which about 5% or less of Bi is added.
As a result, the welding resistance property is significantly inferior. Therefore, this material
The operating mechanism that drives the vacuum valve using the material is Cu-Bi.
It is necessary to design a large detaching force compared to
There is a disadvantage in terms of efficiency and economy. In addition, the anti-fusing metal such as Bi and Te is added to the Cu-Cr alloy.
Added Cu-Cr-Bi alloys are also known. To this alloy
Therefore, although the welding resistance of the material is significantly improved, the baking
Evaporates depending on heat treatment conditions such as gluing and brazing
As the Bi content is different, as a result, the welding resistance varies.
A new problem of twisting occurs. Furthermore, the Cu-Cr contacts have the excellent breaking characteristics described above.
On the contrary, because of this, the breaking current value is high (inferior) and
If the breaking current characteristics are not desirable
It is pointed out that it is in a bad state. (Problems to be Solved by the Invention) As described above, conventional Cu or / and Ag-Cr-based contact materials
In terms of improving both welding resistance and cutting characteristics
Is not always completely satisfactory. The present invention has been made in view of the above-mentioned problems of the conventional technology.
And excellent in both welding resistance and cutting characteristics.
-Provide Cr-based contact materials to improve the reliability of vacuum valves.
It is the one to try. That is, the present invention is directed to the welding tripping force at the contact.
Reduction and reduction of the variation width, and the breaking current value
Vacuum valve connection with reduced and narrowed variation
The purpose is to provide a point alloy. [Structure of the Invention] (Means and Actions for Solving Problems) Outline The present inventors have provided a Cu or / and Ag—Cr-based contact material.
Stabilization of welding resistance and breaking current characteristics of a vacuum valve
Therefore, as a result of various studies, the present invention was completed.
It is a thing. That is, the vacuum valve contact alloy according to the present invention,
(A) An arc resistant material consisting of Cr with an average particle size in the range of 44 to 250 μm, (b) consisting of Cu or / and Ag
High-conductivity material, and
It has a low solid solubility and is equivalent to the above arc resistant materials.
Has a low vapor pressure and is smaller than the arc resistant material
Formed by an auxiliary material, which has an average particle size
It has a feature. In the present invention, an alloy material composed of Cu (or / and Ag) and Cr
In the Cu (or / and Ag) region,
Since it has a structure in which fine auxiliary components are dispersed, Cu
(Or / and Ag) part is also fine and dispersed by this auxiliary component
It becomes a morphology (that is, Cu part and auxiliary components are highly
And the arc is Cu (or / and
Significant roughening, as is often the case when adhered to the Ag) part
Or effectively prevent welding on a large area.
As a result, it contributes to the improvement of welding resistance. Furthermore,
With such a high degree of fine dispersion, the fluctuation range of the breaking current value
It also has a positive effect on the reduction of
You can get the top at the same time. In addition, in the present invention, as a property of the auxiliary component, Cu
(Or / and Ag) Material with a remarkably small solid solubility
Since the material is selected, the auxiliary component is Cu (or / and A
It does not form a solid solution with or form compounds.
Therefore, it is possible to easily and stably obtain the fine and highly dispersed particles.
To be In addition, the vapor pressure of the auxiliary component should be equal to or lower than that of Cr.
Therefore, only this auxiliary component selectively loses priority.
Therefore, the effect of the above fine high dispersion is
It can be obtained stably even after repeated disconnections. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described based on specific embodiments,
First, the structure of a vacuum valve to which the contact material of the present invention is applied.
The formation will be described with reference to FIGS. 1 and 2. FIG. 1 is a vacuum cutoff to which the contact material according to the present invention is applied.
Fig. 1 shows an example of the configuration of the vessel. In the figure, 1 is the isolation chamber.
This cutting chamber 1 is made into a substantially cylindrical shape by an insulating material.
Formed insulating container 2 and sealing metal fittings 3a, 3b at both ends
It is vacuum-tightly constructed with the metallic lids 4a, 4b provided via
Has been. Then, in the shut-off chamber 1, conductive rods 5, 6
A pair of electrodes 7,8 mounted on opposite ends of the
The upper electrode 7 is a fixed electrode and the lower electrode 8 is a movable electrode.
I am trying. In addition, the electrode rod 6 of the movable electrode 8 is
The vacuum chamber 9 is attached to the vacuum chamber 1
This enables the axial movement of the stray electrode 8. Again this
Above the bellows 9 is a metallic arc shield 10
To prevent the bellows 9 from being covered with arc vapor.
There is. Further, 11 is a shield so as to cover the electrodes 7 and 8.
Insulation capacity is provided by a metallic arc shield installed inside the chamber 1.
It prevents the vessel 2 from being covered with arc vapor. Furthermore
The electrode 8 is attached to the conductive rod 6 as shown in an enlarged view in FIG.
It is fixed by brazing part 12 or by caulking.
Are connected by crimping. The contact 13a is brazed to the electrode 8 1
It is fixed at 4. In addition, 13b in FIG. 1 is a fixed side
It is a contact point. The contact material of the present invention is a composite of the contacts 13a and 13b as described above.
Suitable for configuring either or both
It Here, the considerations for obtaining the contact material of the present invention are explained.
Reveal. Studies have shown that the instability of Cu-Cr based contact materials is
Fluctuation of composition in Cu-Cr base alloy, particle size of Cr particles, particle size distribution
Cloth, degree of segregation, degree of voids present in the alloy
Turned out to depend. And these solutions are raw materials
Admitted that selection of Cr and control of sintering technology are effective
However, in order to improve the maintenance of stability,
In addition to ,, and management of finer materials and sintering technology
Was found necessary. That is, the above characteristics and
Instability is the size of the arc-resistant component made of Cr (usually particle size)
Correlation between sizes of highly conductive materials such as Cu and Cu
Found that there is. To improve the current cutoff characteristics, lower the current cutoff value itself.
In addition to maintaining a high value,
Both are extremely important. The current interruption phenomenon occurs between contacts
Amount of steam (vapor pressure, heat conduction), thermoelectric emission from contact material
It is said that it is closely related to children, etc.
It was found that those who contributed more. Therefore,
Make it easy to supply steam, or connect with a material that is easy to supply.
It turned out that the current interruption phenomenon can be mitigated by creating points
did. Cu containing a large amount of Bi such as 10% or more
Bi alloy is based on this point of view and has a low threshold value.
However, the fatal drawback is that Bi has a low melting point (271
℃), the temperature around 600 ℃ usually performed with a vacuum valve.
Melting of Bi during baking or brazing at 800 ℃
As a result of migration and aggregation due to electric shock, current breaking characteristics should be maintained
The existence of Bi becomes uneven. Therefore, the current
It was confirmed that the variation range of the cutoff value increases. On the other hand, Ag-refractory materials represented by Ag (or / and Ag) -Cr
In alloys with alloys, at the boiling point of the arc resistant material (Cr in this case)
Although it depends on the amount of vapor of Ag (or Cu), on the other hand,
In the Cu-Bi system, that of Ag is remarkably higher than that of Bi
Since it is low, the position of the contact point (arc resistant material or Ag) arcs
Depending on whether the feet of the
I invite my legs. And as a result, the current threshold
It was confirmed that the variation range appears. Like this
The sudden temperature drop of the contact surface at the end of the flow interruption is caused by the arc resistant material and Ag.
(Or Cu) only prevents the alloy from blocking the alloy.
It is already considered to be the limit to sustain
In order to improve performance, it is necessary to give some kind of assistive technology.
I came to the conclusion that there is. According to the research of the present inventors, the arc-resistant material (Cr) is
In particular, improvement of the variation width was observed. Obey
Therefore, the grain size of the arc-resistant material plays an important role in the current interruption phenomenon.
In addition to suggesting that the arc-resistant material is
It is notable for contact materials that show segregation in the size of 10 to 20 times.
Considering the observation results showing the variation,
It was found that there was a fence. Thus, the Cu-Bi alloy and Ag-Cr alloy (Ag-arc resistant material
The results of the two studies are that the current cutoff characteristics are stable.
New auxiliary technology is required as a contact point, and the condition is
It is not possible to have stability in heat treatment such as baking.
It suggests that it is essential. That is, the resistance made of Cr
Rationalization of particle size range by introducing arc material and auxiliary material
By choosing, the substantial distribution of highly conductive components is
More uniform than before, to stabilize the current cutoff characteristics.
And are required. That is, in the Cu-Cr alloy, the particle size of Cr powder is
The difficulty of manufacturing technology and contact characteristics to obtain various Cu-Cr materials
Have an important effect on sex itself. The surface of highly active Cr powder (grain) is usually ₂ O ₃ Film
You cannot ignore what is generated by. for that reason,
If the average particle size of Cr powder is too small, the resulting Cr skeleton
If the gas content of the gas becomes large and conversely it is too large,
However, it is difficult to obtain a homogeneous material, so the average particle size of Cr is
Is selected to be 44 to 250 μm. That is, when the average particle size of Cr powder is less than 44 μm, the activity of
The amount of the contamination film on the high Cr surface is relatively large,
There are technical problems in industrial control in a clean state.
Cu-Cr using Cr powder in such a state as a raw material
In alloys, skeletons after sintering or / and infiltration or
And / or often creates unwanted porosity in the contact material
It becomes easier, and the amount of adsorbed or built-in gas increases accordingly.
It tends to remain as a contact alloy as a vacuum valve.
Is not a preferable material. However, variations in the characteristics of Cu-Cr contacts (for example, welding resistance
Characteristics and breaking current characteristics) are related to the physical properties of materials such as Cu and Cr.
There is a mixture of substances with markedly different characteristics.
In order to make sure that the arc point is Cu or Cr,
Since the electrical characteristics of the contact differ greatly,
We have obtained the knowledge that it will occur. Therefore, Cu and Cr are fine
In addition, the fact that they are distributed evenly means that
It is advantageous because it is reduced. In the present invention, especially of Cr
The lower limit of 44 μm means that a sound Cu-Cr material is obtained.
From the viewpoint of the above, it is originally a contact material for vacuum valves.
As a material, the use of finer Cr, as described above,
Clearly, it is beneficial to reduce the variation range. Only
However, in the present invention, the benefit of miniaturization is reduced to Cr with defects.
Therefore, it has a certain condition that is more stable than Cr.
For the use of auxiliary materials, ie, carbides such as W, borides
Therefore, it was achieved. Moreover, when the average particle size of Cr powder exceeds 250 μm, Cr particles are
Increased contact between u, i.e., the arcing point is Cu-Cr
The preferred state across minutes is reduced, only Cu or Cr
There is a disadvantage that the number of cases increases. That
As a result, the deterioration of the welding resistance characteristics (increased welding removal force and
Variation range) and deterioration of cutting characteristics (breaking voltage)
The increase of the flow value and the variation width of
For the auxiliary material of the present invention (carbide such as W, boride)
Addition of (excellently possessed by Cu-Cr alloys)
Within the range to maintain and secure other contact characteristics such as breaking characteristics
Then, the particle size is outside the range that cannot be improved. As described above, in the present invention, the Cu-Cr contact material
High breakdown voltage and high current interruption characteristics such as cutoff characteristics and withstand voltage characteristics
Function while maintaining other functions, especially welding resistance and cutting.
Originally, finer Cr powder should be used to improve current characteristics.
Where necessary, other stable auxiliary materials (carbonization such as W
When fine Cr is adopted by adding
To achieve the above objectives while avoiding the disadvantages of
It is something. In order to obtain the above effect more stably, restrictions on the Cr particle size
In addition to certain restrictions on the auxiliary materials used in the present invention,
is necessary. As the auxiliary material as the third component used in the present invention,
In particular, a metal selected from the group consisting of Mo, W, Ti and Cr
Carbides or borides of the above can preferably be used. In addition, the selection of the particle size of the above-mentioned auxiliary material is also based on the gist of the present invention.
Extremely important. The reason is that the arc resistant material made of Cr
This is the same as selecting the particle size of the material. That is, the particle size of the auxiliary material
When the value is less than 0.5 μm, there is a large amount of agglomeration of auxiliary materials.
Seen and Cu (or / and Ag) after sintering / infiltration
-Cr-There are many residual pores (holes) in the auxiliary material system.
From the consideration of eliminating quality variations.
It When the particle size of the auxiliary material exceeds 10 μm,
There are many chances that the arc point will hit only the auxiliary material,
Unfavorable results for the purpose of compression of the variation width of sex
Bring fruit. Therefore, the particle size of the auxiliary component is 0.5-10 μm.
Selection from the range of m is particularly preferred. By the way, the above particle size range of the auxiliary component is not limited to the above-mentioned range of the present invention.
In order to achieve that purpose, the arc-resistant material made of Cr
It has a correlation with the particle size of the material. That is, it depends on the Cr grain size.
When the particle size of the auxiliary component is large, Cu or / and Ag
It is clear that there is no effect of finely dispersing the conductive material
It is. Therefore, in order to achieve the object of the present invention,
The component is a particle size sufficiently smaller than Cr, for example, 1/10 or less
Is preferred. Generally, the particle size (B) of Cr and
The ratio D / B with the particle size (D) of the auxiliary component should be 0.2 or less.
In the direction. This is also shown in Examples 1 to 18 described later.
Has been done. Moreover, the auxiliary component is a conductive material made of Cu (or / and Ag)
A material having little solid solubility in the material is preferable.
Reasons for using such a material that is difficult to form a solid solution as an auxiliary material
Due to the formation of a solid solution of the conductive material and the auxiliary material
Prevents a decrease in conductivity, and
This is to ensure the rated current carrying capacity. Therefore, the condition
Specific examples of materials satisfying the above are W, Mo, Ti and the like as described above.
Carbide of at least one metal selected from Cr and Cr
Kubo is advantageous. In addition, the auxiliary material is equivalent to or better than the arc resistant material made of Cr.
It must have a vapor pressure below. The reason is,
If an auxiliary material with a higher vapor pressure than Cr is used, the auxiliary material
Material preferentially evaporates selectively, and Cu or / and / or
The effect of finely dispersing a highly conductive material made of Ag is improved.
It is lost along with the evaporation loss of the auxiliary material, which is why
The contact characteristics fluctuate with opening / closing or interruption.
It is. The vapor pressure of the auxiliary material is at least the same as that of the arc resistant material.
If it is equal, the selective loss as described above does not occur, and it is
There is no problem because it evaporates to. Under such conditions,
Thing or boride is satisfied. Furthermore, when using the above auxiliary materials, Cr-auxiliary materials
The amount of Cr in the system is preferably 40 to 90% by volume. That
The reason is that the Cu (or / and Ag) -Cr group has a high breakdown voltage.
This is to make use of the breaking ability, and for that reason Cu-Cr
Add within the above range so that superiority is not impaired. Cr is less than 40%
Is 50% or more of the auxiliary component, and the thermionic emission of the auxiliary component is
It becomes active and the cut-off current characteristics deteriorate. In addition, the total amount of arc resistant material consisting of Cr and auxiliary material is alloy.
If the amount of the material exceeds 80% by volume, the cutoff property
Performance and temperature are not satisfactory. On the other hand, below 20%
Has a relatively large amount of Cu and / or Ag, resulting in welding resistance
Causes a problem. Therefore, the total amount of arc resistant material and auxiliary material
Is important to be in the range of 20 to 80% by volume. In the above contact material, the ratio of Cu and Ag is almost
The eutectic composition (Ag: Cu≈7: 3) is preferable. Further, in the present invention, as an additional component, Bi,
Add 0.1 to 10% by weight of at least one of Pb, Te, Se and Sb
You can also do it. Manufacturing Method Next, an example of a method for manufacturing the contact material will be described.
It Prior to manufacturing, refractory materials and auxiliary materials according to the required particle size
Classify fees. For example, classification work can be carried out by combining sieving and sedimentation methods.
It is possible to obtain a powder having a predetermined particle size by carrying out.
First, for example, a predetermined amount of WC and Cr with a predetermined particle size and a predetermined particle size
Prepare a certain amount of Cu or / and Ag and mix them
Then, pressure molding is performed to obtain a powder compact. Then, the powder compact was placed in a hydrogen atmosphere with a dew point of -50 ° C or lower.
Qi or vacuum is 1 × 10 ^-3 Below Torr, a predetermined temperature such as
Temporary sintering is performed at 950 ° C. for 1 hour to obtain a temporary sintered body. Then, Cu or / and Ag are added to the remaining pores of this temporary sintered body.
For example, 1050 ℃ × 1 hour infiltration with Cu or / and Ag-Cr-WC
Get an alloy. Infiltration is mainly performed in vacuum, but in hydrogen
Can also be done. Here, increase the sintering heat treatment and / or the infiltration heat treatment temperature.
When selected, Ag and / or Cu vaporize rapidly, and the amount of its components
Becomes difficult to control. But the performance of the furnace, or at once
Depending on the amount, size and heat capacity of the material to be heat treated,
Since the theoretical temperature fluctuates, it should be expressed universally.
Is impossible, and the amount of Cu or / and Ag remaining actually is
For example, the method of linearly determining and managing by the X-ray method
However, in general, the temperature of 1300 ° C or higher is selected as Cu or
/ And the presence of Ag are reduced, which is not desirable
It has become. On the other hand, the lower limit temperature is
Is 600 ° C or higher from the viewpoint of degassing raw materials or molded products,
900 ° C or higher is preferable, and in infiltration heat treatment
Need to degas the skeleton and melt Ag
Requires at least 1000 ° C. It should be noted that a welding material containing an anti-fusing material (a very small amount of Te, Bi, etc.)
The point is that when Cu or / and Ag is infiltrated in the above
Or / and an alloy or mixture of Ag and an anti-fusing component
It can be produced by the same technique as above.
It As mentioned above, the particle size of WC, Cr, Ag or Cu should be adjusted appropriately.
Appropriate consisting of Ag or / and Cu depending on your choice
Disperses materials with various vapor pressure values finely and uniformly
This ensures that the arc during interruption will not be
Prevents the arc from remaining locally and the arc is uniform on the contact surface
It is thought to bring about the effect of promoting spreading to
Be done. Therefore, the sintered alloy of the present invention is excellent in current cutting ability.
It is the most suitable as a contact material for vacuum valves. The conditions and methods for evaluating the contact material of the present invention are described below.
Show. Welding resistance A pair of disk-shaped samples with an outer diameter of 25 mmφ have an outer diameter of 25 mmφ and the tip is 100R.
Apply a 100 kg load with the pressure rods forming the spherical surface facing each other 1
0 ^-Five 20 ms current at 50 Hz and 20 KA in mmHg vacuum
Required for tripping between sample and rod at that time
The force was measured to determine the welding resistance. The evaluation is Comparative Example 2
Welding of Cu-Cr alloys containing no auxiliary materials shown in
The comparison was made with a relative value when the force was set to 1.00. The following
Table 1 shows the variation width in the measurement with three contact points. Breaking current value 10 mm in diameter and 4 mm in thickness, one is flat and the other is 200 mmR spherical
Baking and discharging at 400 ℃ on a pair of test contacts with
After aging, coaxial type inserted in series with these
The shunt voltage drop was observed with a synchroscope. Contact
An AC of 44A is applied to the point via L, C, and circuit, and the contact pressure is 10k.
Variation range of breaking current value when opening and closing 300 times with g
Cu-Cr containing no auxiliary material shown in Comparative Example-2
The value of the alloy was set to 1.00 and shown as a comparative value. (Example) Next, an example of each contact material manufactured by the above method, a ratio
The comparative examples are examined and the best content ratio is obtained. As a contact material with low breaking current characteristics,
Cu-13% Bi alloy is known as shown in Comparative Example-3.
It This is pure Cu (Comparative Example-1), Cu-56% Cr (Comparative Example-
2) Although the breaking current characteristic is greatly improved (improved),
With the Cu-Bi alloy, characteristics can be
(Increase in breaking current value) is significantly deteriorated. Examples 1 to 3 and Comparative Examples 4 to 5 Cr powder (arc resistant material) having an average grain size of 105 μm is prepared. Change
First, WC powder (auxiliary material) with an average particle size of 0.1 μm is prepared.
2 tons / cm after mixing them in a ball mill ² Molded in
The obtained molded body is sintered to make a Cr-WC skeleton.
Next, Cu was added to the remaining holes in the skeleton at 1100 ° C.
A Cu-Cr-WC material (Comparative Example-4) was obtained by infiltration. Also, for the same Cr powder, various average particle sizes of 0.5μm and 3.36μ
m, 9.4 μm, 44 μm WC powder is prepared and contact elements are the same as above.
A material was produced (Examples 1 to 3 and Comparative Example-5). These characteristics are shown in Table 1. The amount of highly conductive material Cu and the amount of arc resistant material made of Cr in the alloy
Approximately the same amount, and the particle size of Cr used (about 105 μm)
Despite the same, the particle size of the auxiliary material is 44 μm (compared
In the case of Example-5), both welding resistance and breaking current characteristics
Here, the deterioration of the characteristics can be seen. That is, auxiliary material WC
In comparison with Comparative Example-2, in which the particle size of the auxiliary material is 0.
In 5 (Example-1) to 9.4 (Example-3), the characteristics
A significant improvement can be seen. The presence of auxiliary materials makes the structure finer
Therefore, it contributes to the reduction of the variation width of these characteristics.
is doing. In Comparative Example-1, the auxiliary material is extremely fine.
Is in the material though it tends to improve in terms of welding resistance.
Voids are likely to remain in the
There is a problem in obtaining the material industrially. Therefore auxiliary material grains
The diameter is preferably in the range of 0.5 to 10 μm. Examples 4 to 5 and Comparative Examples 6 to 7 Amount of arc resistant material (A) and amount of auxiliary material (C)
Under the condition that the total of (A + C) is almost constant, these volume ratios
When (A / A + C) fluctuates (however, the highly conductive material C in the alloy
Make a contact material with the same amount of u) by the same method as above.
It was When the amount of (A / A + C) is 0.98 (Comparative Example-6), the auxiliary material is
Is too small, has no effect on the structure in the alloy,
Although there is not much difference from the characteristics of Comparative Example-2, in which
When the amount of + C) was 0.9 (Example-4),
Effective for miniaturization, improved welding resistance and cutting characteristics
Good effect can be seen. Furthermore, the amount of (A / A + C) is 0.4 (Example
In the case of -5), similarly, the improvement of the characteristics was observed, and especially
A remarkable effect is seen in the improvement of the breaking current characteristic. But,
If the amount of (A / A + C) is even smaller and 0.26, the relative
As the amount of auxiliary components increases, the effect of Cr is canceled out.
As a result, the large current cutoff characteristic was deteriorated. Therefore, (A /
The amount of A + C) also has an important effect on the properties of Cu-Cr alloys.
Well, that number should be in the range of 0.4-0.9
I understand. Comparative Examples 8 to 9 Examples 1 to 5 and Comparative Examples 2, 4 to 7 were used.
Examining the particle size of Cr to be used as constant (average particle size 105 μm)
However, the Cr particle size (B) is important for obtaining a sound contact material.
is there. That is, the Cr grain size is 5 μm or less (Comparative Example-
In 8), the amount of highly conductive material Cu and volume% of Cr are the same as above.
Even if (A), the amount of auxiliary material (C), etc. are constant,
There is a large amount of residual gas in the material due to Cr being too fine.
Therefore, it becomes difficult to make the material quality industrially constant.
Furthermore, in the sample with a Cr particle size (B) of 590 μm, the Cr particles are large.
Too much, mixing cannot be performed sufficiently, segregation is observed, etc.
It is difficult to industrially obtain a homogeneous material. Obey
The grain size (B) of Cr in the alloy is 44 μm (Example-6).
The range of up to 250 μm (Example-7) is preferable. Examples 15 to 16 and Comparative Example 10-11 The amount of the highly conductive material Cu in the alloy affects the large current interruption performance.
The cutoff characteristics and welding resistance.
It also affects (Table 3). That is, in the alloy
When the amount of highly conductive material Cu is 89.2% (Comparative Example-10),
Both the adherence and the breaking properties are significantly reduced. This case
Cu that contributes to the reduction of the breaking current of the gold system
The thermal conductivity was too low to supply
It is considered that the threshold value is high. Cu amount 7
If it becomes about 9.8% (Example-15), the above cutting characteristics
Has been improved. On the other hand, when the amount of Cu is 3.8%, conductivity is reversed.
Property, resulting in instability in the amount of Cu supplied to the space.
Appears, and there are variations in the breaking current value.
Not only (Comparative Example-11), but also due to lack of Cu content
The decrease in electrical properties also causes a decrease in blocking characteristics. Combined
When the Cu content in gold is 20.3% (Example-16), the cutting characteristics,
Since both of the welding resistance properties are in a nearly preferable state,
The amount of Cu in gold is balanced in the range of 20-80%. Examples 8 to 14 WC was selected as an auxiliary material to explain the present invention.
The auxiliary material is significantly lower than the highly conductive material as described above.
Has solid solubility and vapor pressure equivalent to or lower than arc resistant materials
If it is, the effect of the present invention can be obtained even if it is other than WC.
That is, the auxiliary material is Mo ₂ C, TiC, Cr ₃ C ₂ , WB, MoB, TiB
₂ , CrB are also effective (Table 2). Example 17-18 Although an example of Cu used as the highly conductive material is shown, even if Ag is used,
(Example-17) Even if it is an Ag-Cu alloy (Example-
-18), welding resistance, and severing characteristics.
An improvement is seen as compared with Comparative Example-2, which has no auxiliary material. Special
A ratio of Ag to Cu of approximately 7: 3 (that is, eutectic composition)
In Example-18, the variation range of the threshold value is remarkably improved. [Effects of the Invention] As can be understood from the results of the above-described embodiments, the present invention
The contact materials for vacuum valves that have
Both have been harmoniously improved, and the variation range has been significantly reduced.
It has a very good effect in terms of doing.