JP2017039967A - Electrode material and method of producing electrode material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance welding resistance and brazability of an electrode material.SOLUTION: There is provided a method of producing an electrode material containing Cu, Cr, heat resistant element and low melting pint metal. A heat resistant element powder and a Cr powder are mixed together at a ratio of heat resistant element<Cr power. The mixed powder of the heat resistant element powder and the Cr powder obtained by mixing is burnt. A MoCr solid solution obtained by burning and containing a solid solution in which the heat resistant element and Cr form solid solution is pulverized and classified. The classified MoCr solid solution powder, a Cu powder, a low melting metal powder having median diameter of 5 μm to 40 μm are mixed together and sintered to obtain the electrode material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrode material used for an electrode such as a vacuum interrupter and a method for manufacturing the electrode material.

  Contact materials for vacuum interrupters are (1) large breaking capacity, (2) high withstand voltage performance, (3) low contact resistance, (4) high resistance to welding, and (5) contact wear. It is necessary to satisfy characteristics such as low amount, (6) low cutting current, (7) excellent workability, and (8) high mechanical strength.

  Since some of these characteristics are contradictory, there is no contact material that satisfies all of the above characteristics. A Cu—Cr electrode material is widely used as a contact material for a vacuum interrupter because it has features such as a large breaking capacity, a high withstand voltage performance, and a high welding resistance. Moreover, in the Cu-Cr electrode material, there exists a report that the one where the particle size of Cr particle | grains is fine is excellent in the surface of interruption | blocking current or contact resistance (for example, nonpatent literature 1).

  In recent years, vacuum interrupters that perform current extinguishing of vacuum circuit breakers have been downsized and increased in capacity, and are required for miniaturization of vacuum interrupters, and have a higher withstand voltage performance than conventional Cu-Cr electrodes. -Demand for Cr-based contact materials is increasing.

  For example, in Patent Document 1, as a Cu—Cr-based electrode material having good electrical characteristics such as current interruption performance and withstand voltage performance, Cu used as a base material and Cr and Cr particles that improve electrical characteristics are finely divided. A method for producing an electrode material is described in which powders of heat-resistant elements (Mo, W, Nb, Ta, V, Zr) are mixed, and then the mixed powder is inserted into a mold and pressure-molded to form a fired body. Yes. Specifically, a heat-resistant element such as Mo, W, Nb, Ta, V, Zr is added to a Cu—Cr-based electrode material made of Cr having a particle size of 200 to 300 μm as a raw material, and Cr is formed through a microstructure technique. And promotes alloying of Cr element and heat-resistant element, increases precipitation of fine Cr-X (Cr in which heat-resistant element is dissolved) inside the Cu substrate structure, and has a diameter of 20 to 60 μm. Cr particles are uniformly dispersed in the Cu substrate structure in a form having a heat-resistant element therein.

  Further, in Patent Document 2, a powder obtained by pulverizing a single solid solution that is a reaction product of a heat-resistant element without passing through a microstructure technique is mixed with Cu powder, pressure-molded, sintered, and electrode structure. It manufactures electrode materials containing Cr and heat-resistant elements.

JP 2002-180150 A Japanese Patent Laid-Open No. 4-334832 JP 2011-108380 A

Rieder, F. ua, “The Influence of Composition and Cr Particle Size of Cu / Cr Contacts on Chopping Current, Contact Resistance, and Breakdown Voltage in Vacuum Interrupters”, IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 12, 1989, 273-283

  However, by forming a finely dispersed structure of arc-resistant metal as described in Patent Document 2, the withstand voltage performance and the breaking performance are improved, but the welding resistance is deteriorated, and a large current is applied during closing. At this time, welding occurs between the electrodes. This decrease in welding resistance has been a factor in increasing the size of vacuum circuit breakers, which has been a problem for mass production.

  Therefore, an attempt was made to produce an electrode material having excellent withstand voltage performance and welding resistance by adding a low melting point metal (for example, Te) to an electrode material having a MoCr finely dispersed structure.

  However, in the sintering process of the MoCr finely dispersed electrode material to which the low melting point metal is added, there is a possibility that voids are generated inside the electrode and the filling rate of the electrode material is lowered. When holes are generated in the electrode material and the filling rate of the electrode material is reduced, brazing material (for example, Ag) is sucked into the holes in the electrode in the brazing process, and brazing of the electrode material becomes difficult. There is a fear.

  In view of the above circumstances, an object of the present invention is to provide an electrode material having excellent welding resistance and brazing properties.

  One embodiment of the electrode material of the present invention that achieves the above object is 1.99 to 29.99 wt% refractory element, 4.99 to 47.98 wt% Cr, and 39.88 to 89.96 wt%. % Of Cu, and a low melting point metal powder of 0.05 to 0.3% by weight with respect to the mixed powder, and a mixed powder in which the low melting point metal powder is mixed. Volume of particles having a particle diameter of 90 μm or less, which is obtained by pulverizing a solid solution of a heat-resistant element containing Cr and a heat-resistant element containing Cr at a ratio of heat-resistant element <Cr by weight ratio. A mixed powder obtained by mixing a solid solution powder having a relative particle amount of 90% or more, a Cu powder, and a low melting point metal powder having a median diameter of 5 μm or more and 40 μm or less is sintered.

  In another aspect of the electrode material of the present invention that achieves the above object, the electrode material has a filling rate of 90% or more, and the Brinell hardness of the electrode material is 50 or more. It is said.

  An embodiment of the method for producing the electrode material of the present invention that achieves the above object is as follows: 1.99 to 29.99% by weight of a heat-resistant element, 4.99 to 47.98% by weight of Cr, and 39.88. A mixed powder containing ˜89.96% by weight of Cu and 0.05 to 0.3% by weight of a low melting point metal powder are mixed with the mixed powder, and the low melting point metal powder is mixed. A method for producing an electrode material obtained by sintering the mixed powder, wherein the heat-resistant element powder obtained by mixing and mixing the heat-resistant element powder and the Cr powder in a weight ratio of heat-resistant element <Cr The mixed powder with Cr powder is sintered, the solid solution containing the heat-resistant element and Cr obtained by sintering is pulverized, and the volume relative particle amount of particles having a particle diameter of 90 μm or less is 90% or more. The solid solution powder, the solid solution powder, the Cu powder, and the median diameter of 5 μm or more and 40 A low melting point metal powder of μm or less is mixed, and a mixed powder in which the low melting point metal powder is mixed is formed and sintered.

  According to another aspect of the method for producing an electrode material of the present invention that achieves the above object, the median diameter of the heat-resistant element powder is 10 μm or less in the method for producing an electrode material.

  In another aspect of the method for producing an electrode material of the present invention that achieves the above object, in the method for producing an electrode material, the median diameter of the Cr powder is larger than the median diameter of the heat-resistant element powder, and is 80 μm or less. It is characterized by being.

  Another aspect of the method for producing an electrode material of the present invention that achieves the above object is characterized in that, in the method for producing an electrode material, the median diameter of the Cu powder is 100 μm or less.

  Moreover, the vacuum interrupter of the present invention that achieves the above object is characterized in that the electrode material is provided as an electrode contact on a movable electrode or a fixed electrode.

  According to the above invention, the welding performance and brazing performance of the electrode material can be improved.

It is a figure which shows the flow of the manufacturing method of the electrode material which concerns on embodiment of this invention. It is a schematic sectional drawing of the vacuum interrupter which has the electrode material which concerns on embodiment of this invention. It is a figure which shows the particle size distribution of Te powder of raw material, and the particle size distribution of Te powder used for manufacture of the electrode material of Example 1. FIG. 2 is a cross-sectional micrograph of an electrode material according to Example 1. It is a figure which shows the flow of the manufacturing method of the electrode material which concerns on the comparative example 1. 2 is a cross-sectional micrograph of an electrode material according to Reference Example 1. It is a figure which shows the flow of the manufacturing method of the electrode material which concerns on the comparative example 2 thru | or the comparative example 5. FIG.

  An electrode material according to an embodiment of the present invention, a method for manufacturing the electrode material, and a vacuum interrupter including the electrode material according to the embodiment of the present invention will be described in detail with reference to the drawings. In the description of the embodiment, unless otherwise specified, the median diameter d50 and the volume relative particle amount are values measured by a laser diffraction type particle size distribution measuring apparatus (Cirrus Corporation: Cirrus 1090L). Further, when the upper limit (or lower limit) of the particle diameter of the powder is determined, it indicates that the powder is classified by a sieve having an opening of the upper limit value (or lower limit value) of the particle diameter.

  Prior to the present invention, the inventors produced an electrode material by a sintering method using a MoCr solid solution powder containing Mo and Cr at a weight ratio of Cr> Mo and Cu powder (for example, a patent application). 2015-93765). This electrode material had a structure in which a MoCr alloy was finely dispersed in a Cu base material, and was an electrode material having superior withstand voltage performance and welding resistance compared to conventional CuCr electrode materials. Also, when using MoCr solid solution powder containing Mo and Cr at a ratio of Cr> Mo by weight ratio, compared to using MoCr solid solution powder containing Mo and Cr at a ratio of Cr <Mo by weight ratio. It became an electrode material with high welding resistance.

  In order to reduce the size of the operation mechanism for opening and closing the electrode in the vacuum circuit breaker, it is desirable to further improve the welding resistance and reduce the peeling force when the electrode material is welded. For this purpose, it is conceivable to add a low melting point metal to the mixed powder of Cu powder and MoCr solid solution powder (for example, Patent Document 3). However, when a low melting point metal is added, the filling rate of the electrode material is lowered, and there is a possibility that the brazing property between the electrode contact and the electrode rod becomes poor.

  Based on the above circumstances, the inventors have intensively studied and completed the present invention. The present invention relates to a composition control technique of Cu—Cr—heat-resistant element (Mo, W, V, etc.) — Low melting point metal (Te, Bi, etc.) electrode material, and limits the median diameter of the low melting point metal powder. By doing so, as compared with a conventional electrode material containing a low-melting-point metal, the filling rate of the electrode material is improved and the brazing property of the electrode material is improved. The electrode material of the present invention is an electrode material that is excellent in withstand voltage performance and welding resistance and excellent in brazing. Therefore, by using the electrode material of the present invention as the electrode contact of the vacuum interrupter, the vacuum interrupter and the vacuum circuit breaker can be miniaturized.

  Examples of the heat-resistant element include molybdenum (Mo), tungsten (W), tantalum (Ta), niobium (Nb), vanadium (V), zirconium (Zr), beryllium (Be), hafnium (Hf), and iridium (Ir). In addition, elements selected from elements such as platinum (Pt), titanium (Ti), silicon (Si), rhodium (Rh), and ruthenium (Ru) can be used alone or in combination. In particular, it is preferable to use Mo, W, Ta, Nb, V, or Zr, which has a remarkable effect of refining Cr particles. When the heat-resistant element is used as a powder, the median diameter d50 of the heat-resistant element powder is, for example, 10 μm or less, so that the particles containing the Cr (including the heat-resistant element and a solid solution of Cr) are uniformly refined. Can be dispersed. The heat-resistant element is contained in the electrode material in an amount of 1.99 to 29.99% by weight, more preferably 1.99 to 10.00% by weight, so that the resistance of the electrode material is reduced without impairing mechanical strength and workability. The voltage performance and current interruption performance can be improved. In addition, since the amount of the low melting point metal contained in the electrode material is very small, the content of the heat resistant element contained in the powder mixed with the low melting point metal powder is regarded as the content of the heat resistant element contained in the electrode material. (Cr and Cu are the same).

  As the low melting point metal, for example, an element selected from elements such as tellurium (Te), bismuth (Bi), selenium (Se), and antimony (Sb) can be used alone or in combination. The low melting point metal can improve the welding performance of the electrode material by containing 0.05 to 0.30% by weight with respect to the electrode material (total weight of heat-resistant element, Cr and Cu). When a low melting point metal is used as a powder, the median diameter d50 of the low melting point metal powder is 5 μm or more and 40 μm or less, more preferably 5 μm or more and 11 μm or less, so that the filling rate of the electrode material is improved.

  Chromium (Cr) is contained in the electrode material in an amount of 4.99 to 47.98% by weight, more preferably 4.99 to 15.99% by weight, without impairing mechanical strength and workability. Withstand voltage performance and current interruption performance can be improved. When Cr powder is used, the median diameter d50 of the Cr powder is not particularly limited as long as it is larger than the median diameter of the heat-resistant element powder. For example, Cr powder having a median diameter of 80 μm or less is used.

  Copper (Cu) is 39.88 to 89.96% by weight, more preferably 79.76 to 89.96% by weight with respect to the electrode material, so that the withstand voltage performance and the current interruption performance are not impaired. The contact resistance of the electrode material can be reduced. By setting the median diameter d50 of the Cu powder to, for example, 100 μm or less, the heat-resistant element, the solid solution powder of Cr, and the Cu powder can be mixed uniformly. In addition, in the electrode material produced by a sintering method, the weight ratio of Cu can be arbitrarily set by adjusting the quantity of Cu powder mixed with the solid solution powder of a heat-resistant element and Cr. Therefore, the total of the refractory elements, low melting point metals, Cr and Cu added to the electrode material does not exceed 100% by weight.

  A method for manufacturing an electrode material according to an embodiment of the present invention will be described in detail with reference to the flow of FIG. In the description of the embodiment, Mo is exemplified as the heat-resistant element and Te is exemplified as the low-melting point metal. However, the same applies to the case where other heat-resistant elements and low-melting-point metal powders are used.

  In the Mo-Cr mixing step S1, heat-resistant element powder (for example, Mo powder) and Cr powder are mixed. The Mo powder and the Cr powder are mixed so that the weight of the Cr powder is larger than the weight of the Mo powder. For example, Mo powder and Cr powder are mixed within a range of Mo / Cr = 1/4 to 1/1 (not including Mo: Cr = 1: 1) by weight ratio.

  In the firing step S2, a mixed powder of Mo powder and Cr powder is fired. In the firing step S2, for example, the mixed powder compact is held in a vacuum atmosphere at a temperature of 900 to 1200 ° C. for 1 to 10 hours to obtain a MoCr sintered body. When the weight of the Cr powder in the mixed powder is larger than the weight of the Mo powder, Cr that does not form a solid solution with Mo remains after firing. Therefore, in the firing step S2, a porous body (MoCr sintered body) containing the MoCr alloy in which Cr is solid-phase diffused into Mo and the remaining Cr particles is obtained.

  In the pulverization / classification step S3, the MoCr sintered body obtained in the firing step S2 is pulverized with a ball mill or the like. The MoCr powder obtained by pulverizing the MoCr sintered body is classified, for example, with a sieve having an opening of 200 μm, more preferably an opening of 90 μm, and particles having a large particle diameter are removed. As detailed in Japanese Patent Application No. 2015-93763, the MoCr powder mixed with the Cu powder is 200 μm or less, more preferably, the volume relative particle amount of particles having a particle diameter of 90 μm or less is 90% or more. By adjusting to, scale-like MoCr (Cr) particles can be removed, and an electrode material excellent in voltage resistance performance and welding resistance performance can be produced. The pulverization time in the pulverization / classification step S3 is, for example, 2 hours per 1 kg of the MoCr sintered body. The average particle size of the pulverized MoCr powder varies depending on the blending ratio of the Mo powder and the Cr powder.

  In the Cu mixing step S4, the MoCr powder obtained in the pulverization / classification step S3 is mixed with the low melting point metal powder (for example, Te powder) and the Cu powder.

  In the press forming step S5, the mixed powder obtained in the Cu mixing step S4 is formed. When a molded body is produced by press die molding, the molded body does not need to be processed after sintering, and can be used as an electrode (electrode contact) as it is.

  In the main sintering step S6, the molded body obtained in the press molding step S5 is sintered to produce an electrode material. In the main sintering step S6, for example, the compact is sintered in a non-oxidizing atmosphere (such as a hydrogen atmosphere or a vacuum atmosphere) at a temperature equal to or lower than the melting point of Cu (1083 ° C.). The sintering time in the main sintering step S6 is appropriately set according to the sintering temperature. For example, the sintering time is set to 2 hours or more.

  In addition, a vacuum interrupter can be comprised using the electrode material which concerns on embodiment of this invention. As shown in FIG. 2, a vacuum interrupter 1 having an electrode material according to an embodiment of the present invention includes a vacuum vessel 2, a fixed electrode 3, a movable electrode 4, and a main shield 10.

  The vacuum vessel 2 is configured by sealing both open end portions of the insulating cylinder 5 with a fixed side end plate 6 and a movable side end plate 7, respectively.

  The fixed electrode 3 is fixed in a state of passing through the fixed side end plate 6. One end of the fixed electrode 3 is fixed so as to face one end of the movable electrode 4 in the vacuum vessel 2, and the end of the fixed electrode 3 facing the movable electrode 4 is in accordance with the embodiment of the present invention. An electrode contact 8 that is an electrode material is provided. The electrode contact 8 is joined to the end of the fixed electrode 3 by a brazing material (for example, an Ag—Cu brazing material).

  The movable electrode 4 is provided on the movable side end plate 7. The movable electrode 4 is provided coaxially with the fixed electrode 3. The movable electrode 4 is moved in the axial direction by an opening / closing means (not shown), and the fixed electrode 3 and the movable electrode 4 are opened and closed. An electrode contact 8 is provided at the end of the movable electrode 4 facing the fixed electrode 3. The electrode contact 8 is joined to the end of the movable electrode 4 with a brazing material. A bellows 9 is provided between the movable electrode 4 and the movable side end plate 7, and the movable electrode 4 is moved up and down while keeping the inside of the vacuum vessel 2 in a vacuum, so that the fixed electrode 3 and the movable electrode 4 can be opened and closed. Done.

  The main shield 10 is provided so as to cover the contact portion between the electrode contact 8 of the fixed electrode 3 and the electrode contact 8 of the movable electrode 4, and the insulating cylinder 5 is protected from an arc generated between the fixed electrode 3 and the movable electrode 4. Protect.

[Example 1]
The electrode material of Example 1 was produced according to the flow of FIG. As shown in FIG. 3, the electrode material of Example 1 is an electrode material produced by classifying Te powder having a median diameter of 48 μm, which is a raw material powder, and using Te powder having a median diameter of 9 μm. In producing the electrode material of Example 1, Mo powder having a median diameter of 10 μm or less, Thermite Cr powder having a median diameter of 80 μm or less, and Cu powder having a median diameter of 100 μm or less were used (other examples, The same powder was used in Comparative Examples and Reference Examples).

  First, Mo powder and Cr powder were mixed so that the mixing ratio of Mo and Cr was Mo: Cr = 1: 4 by weight ratio. After mixing, the obtained mixed powder was transferred to an alumina container and sintered in a vacuum furnace at 1150 ° C. for 6 hours. The porous body, which is a reaction product obtained by sintering, was pulverized and classified to obtain a powder having an under 90 μm.

  This MoCr pulverized powder, Te powder, and Cu powder are mixed in a weight ratio of Cu: MoCr: Te = 80: 20: 0.1, and sufficiently mixed until uniform using a V-type mixer. Mixed. After mixing, the mixed powder was pressure-molded to form a molded body, and this molded body was sintered at a temperature lower than the melting point of Cu to produce an electrode material.

  FIG. 4 shows a cross-sectional photomicrograph of the electrode material of Example 1. Table 1 shows various characteristics of the electrode material of Example 1. The filling rate in Table 1 was calculated by measuring the density of the sintered body and (measured density / theoretical density) × 100 (%). The withstand voltage performance was evaluated by measuring a 50% flashover voltage using each electrode material as an electrode (electrode contact) of a vacuum interrupter. The withstand voltage performance of Reference Example 1 shows a relative value with the electrode material of Comparative Example 1 as a reference (reference value 1.0). Further, the anti-welding performance was evaluated by performing a short-time electric current resistance (STC) test and determining whether or not the electrodes were welded (hereinafter referred to as an anti-welding performance test). Brazing is performed by brazing the electrode material and the Cu lead with an Ag-Cu brazing material, whether or not a fillet has been formed, and hitting the brazed electrode material with a hammer to cause the electrode material to fall off the lead. Evaluation was made based on two points whether or not.

As shown in Table 1, in the electrode material of Example 1, the fillet of the brazing material was confirmed, and the brazing property was good. The volume of the brazing material was 120 cm ³ , and the brazed area of the electrode material was 2.9 cm ² (the same applies to Examples 2 and 3, Reference Example 1, and Comparative Example 1).

[Example 2]
The electrode material of Example 2 is an electrode material produced by the same method as that of Example 1 except that Te powder as a raw material is classified and Te powder having a median diameter of 11 μm is used. . That is, the electrode material of Example 2 was prepared according to the flow of FIG. As shown in Table 1, as a result of confirming the brazeability of the electrode material of Example 2, a fillet of the brazing material was confirmed, and the brazeability was good.

[Example 3]
The electrode material of Example 3 is an electrode material produced by the same method as the electrode material of Example 1 except that Te powder as a raw material is classified and Te powder having a median diameter of 37 μm is used. . That is, the electrode material of Example 3 was prepared according to the flow of FIG. As shown in Table 1, the brazing property of the electrode material of Example 3 was confirmed. As a result, although the fillet of the brazing material could not be confirmed, the electrode could be brazed without peeling off from the lead.

[Comparative Example 1]
The electrode material of Comparative Example 1 is an electrode material that does not contain a heat-resistant element. In producing the electrode material of Comparative Example 1, Te powder having a median diameter of 48 μm as shown in FIG. 3 was used.

  The electrode material of Comparative Example 1 was produced according to the flow shown in FIG.

  First, Cu powder, Cr powder, and Te powder were sufficiently mixed using a V-type mixer at a weight ratio of Cu: Cr: Te = 80: 20: 0.05 until uniform. After mixing, the mixed powder was pressure-molded to form a molded body, and this molded body was sintered at a temperature lower than the melting point of Cu to produce the electrode material of Comparative Example 1. As shown in Table 1, fillets of the brazing material were confirmed, and the brazing property was good.

[Reference Example 1]
The electrode material of Reference Example 1 is an electrode material produced by the same method as in Example 1 except that the median diameter of Te powder mixed in the Cu mixing step S4 is different. That is, the electrode material of Reference Example 1 is an electrode material manufactured using Te powder having a median diameter of 48 μm according to the flow shown in FIG.

  FIG. 6 shows a cross-sectional photograph of the electrode material of Reference Example 1. Further, as shown in Table 1, as a result of confirming the brazing property of the electrode material of Reference Example 1, no braze fillet was formed, the brazing property was poor, and the electrode was peeled off from the lead.

  Although the electrode material of Reference Example 1 has a higher withstand voltage performance and welding resistance performance than the electrode material of Comparative Example 1 (that is, the current CuCrTe electrode material), the filling rate and Brinell hardness decreased. This is considered to be due to the fact that in the electrode material of Reference Example 1, the internal vacancies increase compared to the CuCrTe electrode due to the diffusion reaction of Mo and Cr in the sintering process and the volatilization of Te. If the internal vacancies of the electrode material increase in this way, it is considered that Ag, which is an Ag—Cu brazing material component, is sucked into the internal vacancies of the electrode and brazing cannot be performed.

  On the other hand, as is apparent from the micrograph of FIG. 4, the electrode material of Example 1-3 has small holes generated after Te is volatilized. Thus, the filling rate and Brinell hardness improved to the same level as the electrode material of the comparative example 1 because the internal void | hole became small. As a result, brazing with an Ag—Cu brazing material has become possible. The electrode material of Example 1-3 was not subjected to a withstand voltage test and a welding resistance test, but the filling rate and Brinell hardness increased compared to the electrode material of Reference Example 1, and thus Reference Example 1 It is considered that it has a withstand voltage performance and a welding resistance performance exceeding those of the above electrode materials.

[Examination of amount of low melting point metal added]
Next, electrode materials with different amounts of the low melting point metal were prepared, and the characteristics of the electrode materials were evaluated. Note that Te powder having a median diameter of 48 μm was used in the production of the electrode materials of Reference Examples 2 to 16 and the electrode materials of Comparative Examples 2 to 5. Therefore, it is considered that the brazing property of each electrode material is not good. Therefore, when mounting each electrode material on a vacuum interrupter, a Cu—Mn—Ni brazing material and a Cu—Ag brazing material having a high brazing temperature were brazed together. Thus, even an electrode material with a low packing density can be brazed by devising a brazing material. However, when a plurality of brazing materials are used, there is a risk that a brazing material arrangement order error or a brazing material misplacement may occur, which may make it difficult to apply to mass production.

[Reference Examples 2 to 5]
The electrode materials of Reference Example 2 to Reference Example 5 are electrode materials produced by the same method as in Example 1 except that Te powder having a median diameter of 48 μm was used and the weight of Te contained in the electrode material was different. is there. Therefore, the description of the same manufacturing process as that of the electrode material manufacturing method of Example 1 is omitted. The electrode materials of Reference Example 2 to Reference Example 5 are electrode materials having the same composition and manufactured by the same method, and are samples having different pressure contact forces in the welding resistance test. The pressure contact force is expressed as a relative value with the pressure contact force (αN) of the sample with the smallest pressure contact force (ie Reference Example 6 described later) as a reference value.

  The electrode materials of Reference Example 2 to Reference Example 5 were produced according to the flow of FIG. In the Cu mixing step S4, Cu powder, MoCr pulverized powder, and Te powder are mixed at a weight ratio of Cu: MoCr: Te = 80: 20: 0.05, using a V-type mixer. Mix well until uniform. After the completion of mixing, a molded body was prepared and sintered at a temperature lower than the melting point of Cu to obtain electrode materials of Reference Examples 2 to 5.

  A vacuum interrupter in which the electrode material of Reference Example 2 was mounted as a fixed electrode and a movable electrode was attached to the vacuum circuit breaker. Then, the welding performance test was performed with the pressure force acting between the electrodes of the vacuum interrupter being α + 20N. Similarly, the electrode materials of Reference Example 3 to Reference Example 5 were mounted on the fixed electrode and the movable electrode of the vacuum interrupter, respectively. The pressure contact force applied between the electrodes of the vacuum interrupter was changed to α + 64N (Reference Example 3), α + 87N (Reference Example 4), and α + 131N (Reference Example 5), and the resistance to welding performance was tested on the vacuum circuit breaker. . Table 2 shows the test results of the withstand voltage performance and the welding resistance performance of Reference Examples 2 to 5. The withstand voltage performances of Reference Examples 2 to 16 and Comparative Examples 2 to 6 show relative values with the electrode material of Comparative Example 1 as a reference (reference value 1.0).

  As shown in Table 2, the electrode materials of Reference Examples 2 to 5 were not welded, and it was found that Reference Examples 2 to 5 were electrode materials having excellent welding resistance.

[Reference Examples 6 to 11]
The electrode materials of Reference Example 6 to Reference Example 11 were prepared by the same method as the electrode material of Reference Example 2 except that the mixing ratio of Cu powder, MoCr pulverized powder, and Te powder in Cu mixing step S4 was different. It is. Therefore, different parts will be described in detail. The electrode materials of Reference Example 6 to Reference Example 11 are electrode materials having the same composition and manufactured by the same method, and are samples having different pressure contact forces in the welding resistance test.

  The electrode materials of Reference Example 6 to Reference Example 11 were produced according to the flow of FIG. In the Cu mixing step S4, Cu powder, MoCr pulverized powder, and Te powder were mixed at a weight ratio of Cu: MoCr: Te = 80: 20: 0.1.

  Similar to the electrode material of Reference Example 2, the electrode materials of Reference Example 6 to Reference Example 11 were mounted on the fixed electrode and the movable electrode of the vacuum interrupter, respectively. Then, the vacuum interrupter is attached to the vacuum circuit breaker, and the pressure contact force applied between the electrodes of the vacuum interrupter is αN (Reference Example 6), α + 20N (Reference Example 7), α + 44N (Reference Example 8), α + 64N (Reference Example 9). , Α + 87N (Reference Example 10) and α + 131N (Reference Example 11) were used, and the welding resistance test was performed. As shown in Table 2, the electrode was not welded at all pressures.

[Reference Examples 12 to 16]
The electrode materials of Reference Example 12 to Reference Example 16 were prepared by the same method as the electrode material of Reference Example 2 except that the mixing ratio of Cu powder, MoCr pulverized powder, and Te powder in Cu mixing step S4 was different. It is. Therefore, different parts will be described in detail. The electrode materials of Reference Examples 12 to 16 are electrode materials having the same composition and manufactured by the same method, and are samples having different pressure contact forces in the welding resistance test.

  Electrode materials of Reference Examples 12 to 16 were produced according to the flow of FIG. In the Cu mixing step S4, Cu powder, MoCr pulverized powder, and Te powder were mixed at a weight ratio of Cu: MoCr: Te = 80: 20: 0.3.

  Similar to the electrode material of Reference Example 2, the electrode materials of Reference Example 12 to Reference Example 16 were respectively mounted on the fixed electrode and the movable electrode of the vacuum interrupter. Then, the vacuum interrupter is attached to the vacuum circuit breaker, and the pressure contact force acting between the electrodes of the vacuum interrupter is α + 20N (Reference Example 12), α + 44N (Reference Example 13), α + 64N (Reference Example 14), α + 87N (Reference Example 15). In addition to α + 131N (Reference Example 16), a test for welding resistance was performed.

  As shown in Table 2, when the pressure contact force was α + 20N, α + 44N, α + 87N, welding was performed between the electrodes. On the other hand, when the pressure contact force was α + 64N and α + 131N, the electrodes were not welded. When the pressure contact force was α + 44N, 2450N was required to peel off the welded electrode.

[Comparative Examples 2 to 5]
The electrode material which concerns on the comparative example 2 thru | or the comparative example 5 is an electrode material which does not contain a heat-resistant element (Mo). The electrode materials of Comparative Examples 2 to 5 are electrode materials having the same composition as the electrode material of Comparative Example 1 and manufactured by the same method, and are samples having different pressure contact forces in the welding performance test.

  The electrode materials of Comparative Examples 2 to 5 were produced according to the flow of FIG.

  Cr powder, Te powder, and Cu powder were mixed at a weight ratio of Cu: Cr: Te = 80: 20: 0.05, and mixed well using a V-type mixer until uniform. After the completion of mixing, a molded body was prepared and sintered at a temperature lower than the melting point of Cu to obtain electrode materials of Comparative Examples 2 to 5.

  Similar to the electrode material of Reference Example 2, the electrode materials of Comparative Examples 2 to 5 were respectively mounted on the fixed electrode and the movable electrode of the vacuum interrupter. Then, the vacuum interrupter is attached to the vacuum circuit breaker, and the pressure contact force acting between the electrodes of the vacuum interrupter is α + 44N (Comparative Example 2), α + 64N (Comparative Example 3), α + 87N (Comparative Example 4), α + 131N (Comparative Example 5). In other words, the welding resistance test was conducted.

  As shown in Table 2, in the electrode materials of Comparative Examples 2 to 4, the electrodes were welded, and in the electrode material of Comparative Example 5, the electrodes were not welded. When the pressure contact force is α + 44N, the force to peel off the welded electrode is required to be 2016N.

[Comparative Example 6]
The electrode material according to Comparative Example 6 is an electrode material prepared by the same method as in Reference Example 2 except that it does not contain a low melting point metal (for example, Te). Accordingly, the same manufacturing steps as those of the electrode material of Reference Example 2 shown in FIG.

  The electrode material of Comparative Example 6 was produced according to the flow of FIG.

  In the Cu mixing step S7, the MoCr solid solution powder obtained in the pulverization / classification step S3 and the Cu powder are mixed at a weight ratio of Cu: MoCr = 4: 1 and uniformly using a V-type mixer. Mix thoroughly until complete. After the completion of mixing, a compact was prepared and sintered at a temperature lower than the melting point of Cu to obtain the electrode material of Comparative Example 6.

  Similar to the electrode material of Reference Example 2, the electrode material of Comparative Example 6 was mounted on the fixed electrode and the movable electrode of the vacuum interrupter, respectively. Then, a vacuum interrupter was attached to the vacuum circuit breaker, and the pressure contact force applied between the electrodes of the vacuum interrupter was set to α + 194N, and the welding resistance test was performed. As shown in Table 2, the welding force between the electrodes and the peeled-off electrode was 4080N.

  As can be seen from Table 2, the electrode materials of Reference Examples 2 to 16 and Comparative Example 6 are the current electrode materials of Comparative Examples 2 to 2 by forming a finely dispersed structure of MoCr alloy in the Cu phase. The withstand voltage performance was improved as compared with the electrode material of Comparative Example 5.

  However, although the electrode material of Comparative Example 6 has an excellent withstand voltage performance, the anti-welding performance was low, and the electrodes were welded between the electrodes despite a high pressure contact force. That is, since the electrode material of Comparative Example 6 has a high force for peeling the welded electrode, it is necessary to increase the size of the vacuum circuit breaker incorporating the vacuum interrupter, which may increase the manufacturing cost.

  Therefore, as in the electrode materials of Reference Example 2 to Reference Example 11, when Te, which is a low melting point metal, is added to the electrode material, the welding performance is improved as compared with the electrode material of Comparative Example 6 without impairing the withstand voltage performance. Can be improved. This is because, when a low melting point metal is added to the electrode material, voids are generated at the Cu-Cr grain boundary and the Cu-MoCr grain boundary, thereby reducing the bond strength of the grain boundary and improving the welding resistance of the electrode material. It is thought that. However, when the amount of Te added to the electrode material increases as in the electrode materials of Reference Example 12 to Reference Example 16, the withstand voltage performance of the electrode material may decrease. This is considered to be due to the fact that the number of vacancies in the electrode material increases as the amount of the low melting point metal added increases, causing a significant decrease in the density of the electrode material. When the density of the electrode material is lowered, the withstand voltage performance of the electrode material is lowered and the contact resistance is increased. Therefore, the low melting point metal added to the electrode material should be 0.3% by weight or less with respect to the electrode material, so that an electrode material having excellent welding resistance can be obtained without degrading the withstand voltage performance and the current interruption performance. It is thought that it can be obtained.

  Thus, by adding a small amount of a low melting point metal (for example, 0.05 to 0.3% by weight of Te to the total weight of Cu, Cr, and Mo) to the CuCrMo electrode material, the electrode material is resistant to welding. Performance can be improved.

  However, although the bonding strength of the grain boundary is lowered by the generation of vacancies at the grain boundary, the filling rate of the electrode material may be lowered. For example, in the electrode material of Reference Example 1 in Table 1, the filling rate is 89.2%. Thus, when the filling rate of an electrode material falls, there exists a possibility that the brazing property of an electrode material may fall.

  On the other hand, a firing process of a CuCrMoTe electrode in which a finely dispersed structure of a CrMo alloy is formed by using a Te powder having a median diameter adjusted to 5 μm or more and 40 μm or less as in the electrode materials of Examples 1 to 3. Can reduce the pores generated and the hardness and filling rate of the electrode material can be improved.

  That is, according to the electrode material and the electrode material manufacturing method according to the embodiment of the present invention, by using the low melting point metal powder having a median diameter of 5 μm or more and 40 μm or less, the withstand voltage performance and current interruption performance of the electrode material are improved. An electrode material excellent in welding resistance and brazing can be obtained without lowering. As a result, it became possible to braze with an Ag—Cu brazing material that could not be realized with an electrode material using a conventional low melting point metal powder. In addition, the excellent brazing property reduces the manufacturing cost and the yield in mass production.

  Furthermore, according to the method for manufacturing an electrode material according to the embodiment of the present invention, an electrode material having a filling rate of 90% or more and a Brinell hardness of 50 or more can be obtained. Such an electrode material having a high density and hardness is an electrode material having excellent withstand voltage performance and low electrode wear.

  Moreover, according to the manufacturing method of the electrode material which concerns on embodiment of this invention, an electrode material with a high filling rate can be manufactured. Since this electrode material has an excellent withstand voltage performance due to having a MoCr finely dispersed structure and a welding resistance higher than that of the current Cu—Cr electrode, it is possible to reduce the size of the vacuum interrupter. That is, the withstand voltage performance of the electrode contact of the vacuum interrupter is improved by providing the electrode material of the present invention on at least one of the fixed electrode and the movable electrode of the vacuum interrupter (VI), for example. When the withstand voltage performance of electrode contacts is improved, the gap between the movable and fixed electrodes can be shortened and the gap between the electrode and the insulating cylinder can be shortened compared to the conventional vacuum interrupter. Therefore, the structure of the vacuum interrupter can be reduced. In addition, by improving the welding resistance of the electrode material, the operating mechanism for opening and closing the vacuum circuit breaker can be miniaturized, contributing to the miniaturization of the vacuum circuit breaker.

  In the above description of the embodiment, the preferred embodiment of the present invention has been shown and described. However, the electrode material manufacturing method and electrode material of the present invention are not limited to the embodiment, and do not impair the characteristics of the invention. The design can be changed as appropriate, and the changed design also belongs to the technical scope of the present invention.

  For example, the MoCr solid solution powder is not limited to a powder produced by pulverizing and classifying Mo powder and Cr powder, and a MoCr solid solution containing Mo and Cr at a weight ratio of Cr> Mo. Powder can be used. Moreover, as the MoCr solid solution powder, for example, an electrode material having an excellent withstand voltage performance can be produced by using a powder having a cumulative 50% and 80 μm or less.

DESCRIPTION OF SYMBOLS 1 ... Vacuum interrupter 2 ... Vacuum container 3 ... Fixed electrode 4 ... Movable electrode 5 ... Insulating cylinder 6 ... Fixed side end plate 7 ... Movable side end plate 8 ... Electrode contact (electrode material)
9 ... Bellows 10 ... Main shield

Claims (7)

1.99 to 29.99% by weight of a heat-resistant element;
4.99 to 47.98 wt% Cr;
Mixed powder containing 39.88-89.96 wt% Cu;
An electrode material obtained by mixing 0.05 to 0.3% by weight of a low melting point metal powder with respect to the mixed powder and sintering the mixed powder in which the low melting point metal powder is mixed,
A solid solution powder having a volume relative particle amount of 90% or more of particles having a particle diameter of 90 μm or less, obtained by pulverizing a solid solution of a heat resistant element containing Cr and a heat resistant element containing Cr at a ratio by weight of <Cr An electrode material obtained by sintering a mixed powder obtained by mixing Cu powder and a low melting point metal powder having a median diameter of 5 μm or more and 40 μm or less. The filling rate of the electrode material is 90% or more,
The electrode material according to claim 1, wherein the electrode material has a Brinell hardness of 50 or more. 1.99 to 29.99% by weight of a heat-resistant element;
4.99 to 47.98 wt% Cr;
Mixed powder containing 39.88-89.96 wt% Cu;
This is a method for producing an electrode material obtained by mixing 0.05 to 0.3% by weight of a low melting point metal powder with respect to the mixed powder and sintering the mixed powder in which the low melting point metal powder is mixed. And
Heat-resistant element powder and Cr powder are mixed at a weight ratio of heat-resistant element <Cr.
Sintering mixed powder of heat-resistant element powder and Cr powder obtained by mixing,
The solid solution containing the heat-resistant element and Cr obtained by sintering is pulverized to obtain a solid solution powder having a particle diameter of 90 μm or less and a volume relative particle amount of 90% or more,
Mixing the solid solution powder, Cu powder, and low melting point metal powder having a median diameter of 5 μm to 40 μm,
A method for producing an electrode material, comprising molding and sintering a mixed powder in which the low melting point metal powder is mixed. The method for producing an electrode material according to claim 3, wherein the median diameter of the heat-resistant element powder is 10 μm or less. The method for producing an electrode material according to claim 3 or 4, wherein a median diameter of the Cr powder is larger than a median diameter of the heat-resistant element powder and is 80 µm or less. The method for producing an electrode material according to claim 3, wherein a median diameter of the Cu powder is 100 μm or less. A vacuum interrupter characterized in that the electrode material according to claim 1 or 2 is provided as an electrode contact on a movable electrode or a fixed electrode.