JP6145285B2 - Electrical contact material, method for producing the same, and electrical contact - Google Patents

Description

  The present invention relates to an electric contact material used for an electric contact of an electric device or an electric circuit, a manufacturing method thereof, and an electric contact using the same. The electrical contacts may be used in various switching devices such as electrical circuit breakers, disconnectors and switches.

  As electrical contacts used for circuit breakers, disconnectors and switches used in high-voltage, high-current circuits such as power transmission and distribution networks, electrical contacts using W and Cu composite materials, W and Ag composite materials, etc. Has been proposed.

  When a large current is opened and closed, an arc is generated between the two electrical contacts that are opened and closed.

It takes time for the arc generated by opening and closing the contacts to extinguish. For this reason, the contact portions located at both ends of the arc are continuously exposed to high heat until the arc is extinguished. This phenomenon is not easily solved even if the inside of the apparatus is filled with an atmosphere in which the arc is likely to disappear (for example, in SF ₆ gas).

  The contact material is preferably a good conductor. In addition, the electrical contact is preferably made of a material that is difficult to melt and evaporate by an arc. However, it is difficult to solve the problem using a single material. Therefore, a Cu-W material or an Ag-W material, which is a combination of a good conductor and a material having a high melting point and a high boiling point, is mainly used for the application.

  For example, the Cu—W material may not have a structure in which W is dispersed in a Cu matrix, but may have a structure in which Cu is filled in a skeleton of W having continuous open pores. In this structure, not only W but also Cu is continuous. If W or Mo has a skeleton structure, even if Cu or Ag having a low melting point is melted, W or Mo does not shed (remains in a state held by adjacent W or Mo particles). The exhaustion of is difficult to progress. On the other hand, if W or Mo is dispersed in Cu or Ag, when Cu or Ag having a low melting point is melted, W or Mo in a particle state is shed and the contact material is consumed. It's easy to do.

  As described above, the arc generated by opening and closing of the electrical contact may cause the electrical contact to largely evaporate and wear, so that there is a problem that the life is not sufficient.

  Therefore, in many prior art documents, electrical contact materials using a Cu—W material as a basic material are shown. Such an electrical contact material can be obtained by adding various substances to the Cu-W material.

  Patent Document 1 discloses an arc-resistant conductive material made of a W group or a WC group alloy, a rare earth element, a rare earth oxide, or the like. In particular, it is described that the amount of contact consumption is greatly reduced in an electrical contact material containing a rare earth oxide. Moreover, the addition of rare earth oxides deteriorates the wettability with Ag in the W-based material and makes it easy to generate pores. Therefore, it is disclosed that pores are reduced by further adding Fe, Co, Ni, and Cu.

  Patent Document 2 includes a first component composed of W and Mo, a second component composed of silver (Ag) or copper (Cu), and a third component composed of a boride such as strontium boride and lanthanum boride. Including electrical contact materials are disclosed. Further, it is described that the characteristics of the electrical contact material can be improved by adding any of Cr, Fe, Rh, Ru, and Ir to the second component of the electrical contact material.

  If an electrical contact is produced using a material having the above composition, the consumption amount of the electrical contact, the welding resistance, and the contact resistance can be improved.

Japanese Unexamined Patent Publication No. 63-083242 JP 2002-294384 A

  However, as a result of the study by the present inventor, it has been found that in the conventional electrical contact, wear may easily proceed due to an arc generated by opening and closing of the electrical contact.

  This invention is made | formed in view of the said subject, and it aims at providing the electrical contact which can exhibit a high arc-proof characteristic, maintaining favorable electrical conductivity. It is another object of the present invention to provide an electrical contact material that can further suppress wear against an arc generated by opening and closing the electrical contact.

  The electrical contact material according to the embodiment of the present invention is an electrical contact material made of a material in which the sum of the masses of the following (A), (B), and (C) occupies 95% by mass to 100% by mass of the total mass. (A): 5 to 50 parts by mass of M1, (b): M2 and an iron group metal element are necessarily included, and (a) in total, 100 parts by mass of M2, an iron group metal and / or M2 and an iron group metal And (c) 0.05 to 8 external parts by mass of M3 borate and / or the composition of M3 borate with respect to 100 parts by mass of the total mass of (a) and (b) . However, M1 is any one or two of Cu or Ag and alloys thereof, M2 is any one or two of W or Mo and alloys thereof, and M3 is One or more of Ca, Sr, Ba, Mg, and rare earth metals, and the composition of the M3 borate includes boron oxide, the M3 oxide, and / or carbonate. including.

In one embodiment, part or all of the M3 borate of (c) is decomposed, and boron oxide (B ₂ O ₃ , B ₂ O ₂ , B ₄ O ₃ .2H ₂ O, B _{4 is used.} Any one or more of O ₅ ) and any one or more of M3 oxide (M3 ₂ O ₃ , M3O ₂ ) and / or M3 carbonate (M3CO ₃ ). ing.

  In one embodiment, the total of the mass of the iron group metal and the mass of the alloy of M2 and the iron group metal is 0.005 to 100 parts by mass of the total mass of (A) and (B). Occupies 1 part by mass.

In one embodiment, the borate of (c) can be represented as M3 _a B _b O _c, and the first borate represented by a = 2, b = 2, c = 5, and a = 1, b = 2, and / or a second borate represented by c = 4.

  An electrical contact according to an embodiment of the present invention is an electrical contact configured using any of the electrical contact materials described above.

  The manufacturing method of the electrical contact material according to the embodiment of the present invention includes (b): 5 to 50 parts by mass of M1, and (b): (b) and 100 parts by mass of M2 and iron. A step of preparing a group metal, and (c) 0.05 to 8 parts by mass of M3 borate and / or M3 boron with respect to 100 parts by mass of the total mass of (a) and (b) Providing an oxide component. However, M1 is any one or two of Cu or Ag and alloys thereof, M2 is any one or two of W or Mo and alloys thereof, and M3 is One or more of Ca, Sr, Ba, Mg, and rare earth metals, and the composition of the M3 borate includes boron oxide, the M3 oxide, and / or carbonate. including. Moreover, the process of forming a skeleton alloy using said (b) and said (c), and the process of infiltrating said (a) to the said skeleton alloy are included.

  In one embodiment, the step of preparing (c) comprises preparing the boron oxide powder and the M3 oxide or carbonate powder as a constituent of the M3 borate, A step of mixing and heat-treating the boron oxide powder and the M3 oxide or carbonate powder.

  According to the embodiment of the present invention, it is possible to obtain an electrical contact material that is suitably used as a contact point of various switchgear devices such as a circuit breaker, a disconnector, and a switch that mainly cut off a large current. An electrical contact manufactured using the electrical contact material according to the embodiment of the present invention is relatively less consumed by opening and closing of a circuit breaker or the like than a conventional electrical contact, and has a relatively long life.

It is a schematic diagram of the structure | tissue of the electrical contact material of this invention. It is a schematic diagram of a switch. It is a schematic diagram of consumption of electrical contacts. (A) shows the figure before use, (b), (c) and (d) show the figure after use. It is a figure for demonstrating the mechanism (conventional electrical contact) of electrical contact consumption. It is a figure for demonstrating the mechanism (electrical contact of embodiment of this invention) of electrical contact consumption. It is a figure which shows one form of the switch of this invention.

  According to an embodiment of the present invention, in addition to the basic configuration of the contact material of M1-M2 (an example is Cu-W), an iron group metal (and an alloy of M2 and an iron group metal), and an M3 boron An electrical contact material comprising an oxide is provided.

  Here, M1 refers to any one or two of Cu or Ag and alloys thereof. M2 refers to any one or two of W or Mo and alloys thereof. M3 refers to any one or more of Ca, Sr, Ba, Mg, and rare earth metals. Moreover, the said iron group metal points out any 1 type, or 2 or more types of metals of Fe, Co, and Ni.

The M3 borate (for example, SrB ₂ O ₄ ) may be present in the contact material in a partially or completely decomposed state. The M3 borate may be composed of a plurality of alternative materials. In the present specification, these materials may be referred to as “a constituent of M3 borate”. The “M3 borate composition” includes M3 oxide (eg, SrO ₂ ) and / or carbonate (eg, SrCO ₃ ) and boron oxide (eg, B ₂ O ₃ ). The contact material according to the embodiment of the present invention may include only one of “M3 borate” and “M3 borate composition” or, of course, both. However, typically, M3 borate is included.

  Hereinafter, a process of changing a switch having an electrical contact from a closed state to an open state will be described mainly with reference to FIGS.

FIG. 2 is a schematic diagram of a circuit breaker 10 including a switch and a sealed container 5 that houses the switch. In the upper part of FIG. 2, a first contact (breaker member) 1A having an electrical contact 1 at the tip is shown. Further, in the lower part of FIG. 2, a second contact 1 </ b> B having the same electrical contact 1 is shown. The first contact 1 </ b> A and the second contact 1 </ b> B are accommodated in the sealed container 5. The sealed container 5 is filled with SF ₆ gas 4.

  The first contact 1A and the second contact 1B electrically connect the electrical contact 1 that opens and closes the arc at the tip, the shank 2 that is a good conductor that holds the electrical contact 1, and the circuit outside the sealed container, respectively. It has a lead 3.

  When a large current is interrupted by this switch (that is, the contact is changed from the closed state to the open state), an arc is generated between the first contact 1A and the second contact 1B. It is difficult to observe the occurrence of the arc directly. Therefore, the detailed behavior at the time of occurrence is unknown. However, the behavior can be estimated by observing the first contact 1A and the second contact 1B after use.

  Fig.3 (a) shows the schematic diagram (sectional drawing) of the contact before use. FIGS. 3B, 3C, and 3D are schematic views (cross-sectional views) of the contacts after use.

  After use, as shown in FIG. 3 (b), it is preferable that the contacts are evenly consumed, but actually, as shown in FIGS. 3 (c) and 3 (d), the contact portions are arced. It is not always consumed evenly throughout. In the example shown in FIGS. 3C and 3D, a part of the electrical contact 1 that is close in distance to the opposing contact is extremely consumed, while a portion having the same distance and shape as the opposing contact. However, there are parts that are hardly consumed. When the wear is severe, as shown in FIG. 3 (d), the wear portion 6 may reach the shank 2 or a large number of cracks 7 may occur in the electrical contact. The reason why such a wear imbalance occurs will be described with reference to FIGS.

  4A to 4D are cross-sectional views showing the vicinity of the contact surface when a Cu-W composite material is used as the electrical contact material. The arc 12 starts to be generated from the moment when the contact is opened and a gap is formed (FIG. 4A). At this time, an arc is likely to occur first in a portion having a low work function. Since the work function of each composition is Ag, Cu (M1) <Mo, W (M2) in ascending order, the first arc is likely to be generated from Cu or Ag. Further, the contact is generally finished as a smooth surface so that there is no unevenness on the surface. Therefore, the place where the first arc is generated on the electrical contact surface portion 11 is random.

  Due to the generated arc 12, the material having a low melting point evaporates at a high temperature in Cu and Ag and the surrounding portions, and only a part of W and Mo having a high melting point remains (FIG. 4B). At this time, a worn portion 6 exists in the electrical contact surface portion 11. The surface of the electrical contact is rougher than before the arc occurs. And the uneven surface which consists mainly of W and Mo is formed there.

  The generation point of the next generated arc is selected from one of a part having a low work function and a part having a rough surface and a protruding tip.

  At the time of the first arc generation, as described above, the contact surface is a smoothly finished surface, so that the arc generation location is random. However, the surface of the electrical contact surface has unevenness after the first arc has occurred, since the evaporation is consumed by the first arc. The next arc is very likely to occur in the convex part of the irregularities on the surface of the electrical contact. This is similar to the phenomenon where a lightning strike to a building falls on a protruding lightning rod. The generation of an arc is likely to occur from a portion that has evaporated and consumed due to the previous generation of the arc (FIG. 4C). For this reason, the electric contact is more likely to be locally consumed (FIG. 4D). Contact life (number of uses and number of arcs) is more likely to decrease as a result of local wear.

  In order to avoid this phenomenon, when a convex portion is generated, the next generated arc may be generated at another location other than the convex portion. For this purpose, a large number of locations with lower work functions (typically locations with extremely low work functions) may be provided on the surface. FIGS. 5A to 5D show materials having a structure in which particles 13 having a low work function are dispersed in a Cu—W composite material. With such a structure, after the arc 12 is generated for the first time (FIGS. 5A and 5B), the next arc 12 is generated from a low work function portion provided on the surface of the electrical contact. Occurs (FIGS. 5C and 5D). Therefore, arc generation, evaporation, and consumption occur evenly over the entire surface of the electrical contact, resulting in a long life.

  The inventors selected a borate of one or more metals of Ca, Sr, Ba, Mg, and rare earth metals as a material having a lower work function. In addition, part or all of those borates are decomposed into one or more of boron oxide and Ca, Sr, Ba, Mg, rare earth metal oxides or carbonates, and are described above. It has been discovered that it may be in the form of a borate oxide composition.

  The work function of borate is difficult to measure and it is difficult to obtain the numerical value itself. However, their work functions are estimated to be lower than those disclosed in the prior art, such as boron, boric acid, and oxide, as can be inferred from the examples described later.

  The electrical contact materials are (i) 5 to 50 parts by mass of M1 (Ag, Cu), (b) 50 to 95 parts by mass (= 100 parts by mass in total with (a)), iron group metal, And / or the reason why it is configured to include an alloy of M2 and an iron group metal is that the melting point is high and evaporation / consumption due to the arc is difficult to occur (b) 50 to 95 parts by mass, so that a wide range is achieved by the arc. This is to obtain the feature that it is not consumed at once. In addition, (b) has a high melting point, so that it does not weld with the contact point facing when opening and closing. If (b) is less than 50 parts by mass, the amount of (a) which is a relatively low melting point metal increases. For this reason, the electrical contacts are heavily consumed by the arc, and more easily welded to the opposing contacts. On the contrary, a composition in which (B) exceeds 95 parts by mass is also undesirable because the conductivity is lowered and the impact resistance is lowered.

  In addition, when the amount of M2 is as high as 75 to 95 parts by mass, for example, the sinterability and infiltration of the electrical contact material may be reduced, and the manufacture may be difficult. Therefore, by adding an iron group metal to (b), the reduced sinterability and infiltration can be compensated. That is, the addition of an iron group metal to the composition makes it easier to manufacture the M2 skeleton structure.

  Part or all of the iron group metal is alloyed with the M2 metal and exhibits an effect of further improving the sinterability. On the other hand, iron group metals and alloys of iron group metals and M2 have low electrical conductivity. Therefore, when a certain amount or more of an iron group metal and / or an alloy of iron group metal and M2 is added, there is a risk of adversely affecting the electrical characteristics of the contact. The range in which the above-described advantages are sufficiently exhibited and the electrical characteristics are not deteriorated is, for example, about 0.005 to 1 part by mass in the raw material stage.

  The effect of adding (c) and the reason for selecting the type have been described above. The amount is preferably 0.05 to 8 external parts by mass, with the total mass of (A) and (B) being 100 parts by mass. If the amount of (c) is within this range, a large number of (c) particles are exposed on the contact surface at the time of arc occurrence, and this tends to be the origin of arc generation. When the amount of (c) is less than 0.05 external parts by mass, a sufficient number is not always exposed on the contact surface, and the effect of addition is limited. Further, borate generally has a function of inhibiting sintering and infiltration. Therefore, if (c) exceeds 8 external mass parts, it is difficult to obtain a sufficiently dense electrical contact material. If the electrical contact material is not dense and has pores on the surface or inside, the periphery of the material is likely to be an arc generation point, which inhibits uniform wear. Preventing this is also one of the purposes of adding an iron group metal to the above (b). By containing an iron group metal, an effect of suppressing the inhibition of sintering and infiltration by borate can be expected.

  FIG. 1 is a schematic diagram showing a structure of an electrical contact material according to an embodiment of the present invention. (A) and (b) each have a continuous structure (it appears to be broken in the schematic diagram, but is continuous in the three-dimensional structure). In addition, (b) fills the gap in the skeleton structure of (b). Furthermore, (c) has a structure in which (c) is dispersed around the grain boundary part of (b) and (b) and the inside of the particle of (b).

(C) is partially or completely decomposed to form boron oxide (B ₂ O ₃ , B ₂ O ₂ , B ₄ O ₃ .2H ₂ O, B ₄ O ₅ ) and an oxide of M3 (M3 ₂ O ₃ , M3O ₂ ) or a carbonate (M3CO ₃ ).

  As described above, it is most desirable from the viewpoint of work function that the borate (c) is dispersed in the electrical contact material in the form of the borate as it is. However, some or all of them may be decomposed into boron oxide, M3 oxide, or M3 carbonate during the firing or infiltration process or due to overheating during shaping.

  Boron oxide and M3 oxide (or M3 carbonate) produced by decomposition are not as high as M3 borate, but the presence of a certain amount of both lowers the work function to a sufficient extent to be effective. It is possible. Therefore, the case where a predetermined amount of M3 oxide, M3 carbonate, boron oxide, or the like (a constituent of M3 borate) is included within the scope of the present invention. The constituents of M3 borate are not limited to those produced by decomposition of M3 borate, but may be boron oxide and M3 oxide (or M3 carbonate) added as raw materials.

The borate of M3 is generally expressed in the form of “M3 _a B _b O _c ”. From the viewpoint of easy availability and chemical stability, “a = 2, b = 2, c = 5 "" a = 1, b = 2, c = 4 "It is desirable to include one or both of them. Examples of the former include Sr ₂ B ₂ O ₅ , and examples of the latter include SrB ₂ O ₄ .

  Use of the electrical contact material having the composition shown above as an electrical contact is preferable because it can improve the life while preventing deterioration of electrical characteristics.

  The electrical contact material and electrical contact according to the embodiment of the present invention can be obtained, for example, by the steps described below.

(1) M2 Skeleton Production The M2 skeleton can be produced from a mixture of W2 or Mo powder, which is M2, and iron group metal powder and borate powder. That is, components of the electrical contact material other than Cu and Ag may be added at the stage of manufacturing the M2 skeleton.

  As the W powder and the Mo powder, those having an average particle diameter of about 0.1 to 100 μm and a purity of 99% or more are preferably selected.

  In the present specification, “average particle diameter” means a d50 average particle diameter (a median diameter of 50% cumulative) obtained by a laser analysis method.

  It is preferable to select an iron group metal having a particle diameter as small as possible so that aggregation does not occur. Those suitable for use are those having an average particle size of 200 μm or less, more preferably 100 μm or less.

  Prior to this mixing step, a desired borate powder is prepared. As the borate powder, for example, a commercially available powder can be used.

  Alternatively, Ca, Sr, Ba, rare earth metal oxides and / or carbonates, and a boron-containing substance such as boron carbide or boron carbonate are mixed and heat-treated in an oxidizing atmosphere, whereby Ca, Sr, Ba and rare earth metal borates can also be obtained. Depending on the oxygen concentration and the heat treatment temperature at this time, borates having different forms (the numbers of a, b and c are different) can be obtained. Further, the obtained borate can be pulverized with an attritor or the like in a non-reducing atmosphere such as an oxidizing atmosphere to obtain a borate powder having a smaller particle diameter.

  The obtained borate powder is mixed with M2 powder and iron group metal powder. For mixing, an attritor, a blender, a Henschel mixer, a ball mill, a raking machine, or the like can be used. In this mixing, W powder and Mo powder are easily oxidized, so it is desirable to perform treatment in a non-oxidizing atmosphere such as a methanol atmosphere. It is preferable to sufficiently mix the iron group metal powder and the borate powder so that they are uniformly mixed.

  Here, when components other than (A), (B), and (C) are intentionally added, the same procedure as the addition of the borate can be performed. That is, it is added in a powder state when the M2 skeleton is manufactured. Components that can be added are, for example, oxides, borides, metals such as Cr, Ti, Zr, and Ta. These components may be included in addition, but because there is basically no function to improve the performance of electrical contacts, in this description, components other than (a), (b) and (c) are intentionally added. A description of the case will be omitted hereinafter.

The obtained mixed powder is subjected to a die press or cold isostatic press molding at about 5 to 150 MPa after adding a molding binder as necessary, and 900 to 900 to a reducing atmosphere such as an H ₂ atmosphere. Heat to about 1600 ° C. It is sufficient if the particles of M2 that have come into contact have reached the state where necking has started. At this point, the pores between the M2 particles are in a continuous state and have sufficient strength for handling. Thus, the M2 skeleton is obtained.

  The added iron group metal forms an alloy with W or Mo and assists the necking of the M2 particles. Thereby, densification can be promoted and the skeleton strength can be increased. On the other hand, borate has extremely low wettability with M2 and hinders softening and necking of M2 particles. For this reason, when a borate was added, it was easy to produce | generate and the M2 skeleton which has a problem in handling property was easy to be produced | generated. For this reason, in the embodiment of the present invention, by adding an iron group metal as described above, an M2 skeleton having sufficient strength for handling and subsequent manufacturing processing can be obtained even when a borate is added. I have to.

(2) Infiltration of M1 into M2 Cu and Ag as M1 are infiltrated into the M2 skeleton obtained in (1).

  In the case of M1: Cu, Ag, if the diameter of the continuous pores of the M2 skeleton is small to some extent, infiltration can be performed by capillary action at a temperature equal to or higher than the melting point of M1.

Infiltration is performed using a heat-resistant container such as ceramics or carbon, and M2 skeleton is embedded in a sufficient amount of M1 for infiltration, and in this state, the melting point of Cu is 1084 in a reducing atmosphere such as an H ₂ atmosphere. It may be carried out by heating to 962 ° C. or higher, which is the melting point of ° C. or Ag. If M1 is sufficiently infiltrated into the M2 skeleton by capillary action, the material is completed. Thus, infiltration can be performed by installing in a state where M1 is melted and in contact with the M2 skeleton.

  The electrical contact material of the present invention can be obtained by processing the obtained material into a desired electrical contact shape.

  Moreover, the electrical contact of this invention can be obtained by removing the excessive infiltration M1 from this material, processing it into a desired shape as necessary, and further joining with a base metal as necessary.

  Examples of the electrical contact material of the present invention will be described below.

Example 1
As raw materials for producing the W skeleton, W powder having an average particle size of about 4 μm and Co and Sr borate powders having an average particle size of about 1 μm were prepared. As Sr borate, commercially available SrB ₂ O ₄ (strontium borate) powder having an average particle diameter of about 5 μm was used.

  These powders were mixed with a Henschel mixer for 30 minutes to obtain a mixed powder.

  Next, a die press was performed on the mixed powder at a pressure of 50 MPa to obtain a cuboid shaped body.

The oxide heat-resistant container is provided with a concave portion where the molded body can be sufficiently accommodated, the molded body is placed therein, sintered at H ₂ atmosphere at 1150 ° C. for 60 minutes, and a skeleton having a theoretical density ratio of about 65% ( The pores were about 35%).

On this skeleton, a sufficient amount of plate-like Cu for infiltration was installed, and in this state, infiltration was performed at 1100 ° C. for 20 minutes in an H ₂ atmosphere to obtain an electrical contact material of an example of the present invention. .

In the obtained electrical contact material, Cu in (a) occupies 20.0 parts by mass, W in (b) occupies 79.9 parts by mass, Co occupies 0.1 parts by mass, ) In total was 100 parts by mass. In addition, 1.0 (c) contained 1.0 part by mass of SrB ₂ O ₄ . Regarding (b), Co and W were partially alloyed.

  Excessive Cu that could not be infiltrated from the obtained material was removed to form a rectangular parallelepiped shape, and by cutting with a milling machine, the four corners of one surface of the rectangular parallelepiped as shown in FIG. The electrical contact chamfered so that the surrounding shape is a smooth arc was obtained.

  Next, the electrical contact 1 was internally chill casted onto a copper shank 2 and joined to the tip of the shank 2. Thereafter, the shank 2 was hardened by forging.

The circuit breaker member which has the electrical contact of the Example of this invention was obtained as a sample 1 in the above procedure. As shown in FIG. 2, the electrical contact portions of the two circuit breaker members were opposed to each other, and the positive and negative electrodes of electricity were connected to the respective end points via the leads 3. Both circuit breaker members were fixed to a sealed container 5 in which high-pressure SF ₆ gas 4 was sealed, and the circuit breaker was connected (current flowed). The applied current is 2500 amperes and the voltage is 230 volts. The thickness of the electrical contact defined in the direction perpendicular to the facing surface is 5 mm. This sample is designated as Sample 1.

  In this state, by operating the operating mechanism of the blocking base member in the airtight container, a test was performed in which the interruption and opening / closing of the current was repeated 10 times.

After the test, the energization was stopped and the SF ₆ gas was exhausted. Then, the circuit breaker member was taken out and the contact portion was investigated.

As a result of observing the appearance, as shown in FIG. 3B, gentle wear occurred over the entire surface of the opposed electrical contacts 1 that were opened and closed. As a result of the measurement, the amount of consumption of the electrical contact 1 was 2.63 mm ³ .

In the example of sample 2, the other conditions are the same as those of sample 1, and (c) is configured to include SrB ₂ O ₄ , B ₂ O ₃ and SrO ₂ . SrB ₂ O ₄ is commercially available, but one with high purity is expensive. Therefore, it was considered to purchase inexpensive B ₂ O ₃ and SrO ₂ powders and heat-treat them in an oxidizing atmosphere in a mixed state to obtain the same. The powder obtained after the heat treatment was not a complete SrB ₂ O _4, and was a mixture in which 10% by mass of B ₂ O ₃ and SrO ₂ remained as a result of analysis. Sample 2 is a sample in which this mixture was used in place of commercially available SrB ₂ O ₄ .

This sample 2 was also tested in the same manner as the sample 1, but the entire surface of the contact was gradually consumed, and the amount consumed was 2.66 mm ³ .

(Example 2)
Next, as shown in the following Tables 1 to 3, the same test as in Example 1 was performed by changing only the electrical contact material. Samples 3 to 50 are samples according to examples of the present invention, and comparative samples 101 to 132 are comparative samples outside the scope of the present invention. Regarding (b), although part or all of M2 and the iron group metal are alloyed, it is difficult to observe in what form it finally exists, so at the time of starting the raw material The mass fraction of was described. As the final product, the phase as (b) is formed in any form of M2 (simple substance), an iron group metal, and an alloy of M2 and an iron group metal.

  In addition, it is known that a slight reaction occurs between M1 and the iron group metal, for example, to form an alloy of Cu—Co, but the alloy is only in a limited region centering on the interface of (a) and (b). The form of these alloys in the final product is not considered because they are considered to be.

  Each sample will be described first from a comparative sample.

  The comparative sample 101 shown in Table 3 is an electrical contact material made only of Cu-W that has been widely used conventionally. The comparative sample 101 has a structure in which Cu is filled in a W skeleton.

  Comparative samples 111-114 are conventional electrical contact materials made by adding a boride (for example, strontium boride) or a rare earth metal oxide to Cu-W.

  Comparative samples 115 and 116 are electrical contact materials in which an iron group metal and an oxide of Y and La are added to Cu-W, or an iron group metal is further added.

  Next, examples of the present invention will be described.

  Samples 3 to 7 are obtained by changing the mixing ratio of Cu (I) and W (or Mo) (B) of Sample 1 respectively. Sample 8 is an example using Ag instead of Cu of sample 5. In the comparative sample 102, the mass ratio of (A) and (B) is outside the scope of the present invention. Sample 6 is an example using Mo as M2.

  Samples 21 to 26 are samples in which the amount of (c) (external mass part) is variously changed in sample 5 that showed excellent performance for (b) and (b). Note that the comparative samples 131 and 132 were the comparative samples having the amount (c) outside the scope of the present invention.

  The samples 31 to 34 shown in Table 2 were tested by changing the type of (c) based on the sample 23 that showed the most excellent performance as (c). In addition, the type of iron group metal (Fe, Co, Ni) contained in (b) is appropriately selected.

Samples 41 to 44 were samples in which part or all of SrB ₂ O ₄ used in Sample 23 was replaced with SrO ₂ and B ₂ O ₃ or SrCO ₃ . Sample 41 is replaced with 10% by mass of SrO ₂ and B ₂ O ₃ in (c), sample 42 is replaced with 25% by mass of SrO ₂ and B ₂ O ₃ , and sample 43 is replaced with sample 43. All SrB ₂ O ₄ was replaced with 50% by weight of SrO ₂ and B ₂ O ₃ . In sample 44, all SrB ₂ O ₄ was replaced with 50% by mass of B ₂ O ₃ and SrCO ₃ . In addition, components other than borate were listed in the column “Others” in Tables 2 to 3.

  Samples 45 to 49 are samples in which the amount and type of the iron group metal contained in (b) in the composition of the sample 31 are changed. (B) of sample 31 is W69.9 parts by mass + Co 0.1 parts by mass, but this composition was changed in the range of 69.0 to 69.995 parts by mass, and the iron group metal was changed to 0.005 to It changed in the range of 1.0 mass part. Sample 48 is an example using Ni as the iron group metal, and sample 48 is an example using both Co and Ni as the iron group metal. Sample 50 is an example of W68.0 parts by mass + Co 2.0 parts by mass.

The electrode material consumption was evaluated by measuring the electrical contact portion with a three-dimensional shape measuring instrument. The volume after use was subtracted from the volume before use to determine the amount of wear (mm ³ ).

  In addition, it was also evaluated whether or not it was consumed evenly as a whole. This evaluation was performed by visually observing whether local consumption as shown in FIGS. 3C and 3D occurred. X was given to the sample that was locally consumed, and A was given to the sample that was evenly consumed on the surface facing the contact as shown in FIG. The results are shown in Tables 4-6.

  The results of Sample 3 to Sample 7 and Comparative Sample 102 show that, in order to cut off a large current, the ratio of (A) and (B) is as follows: (A) Cu is 5 to 50 parts by mass, and (B) W is 50 to 90. It shows that the mass part is good. The comparative sample 102 did not wear or reach the copper shank, and the crack was not reached. It was clear that increasing (A) over the comparative sample 102 further increased the amount of consumption and was difficult to use.

  In terms of the occurrence of wear and cracks, the sample (a) was 30 parts by mass and (b) was 70 parts by mass was particularly excellent.

  Sample 3 was the sample with the largest mass ratio of W (b), but many cracks were observed on the surface after the test. While W has a high melting point, it is a brittle metal and has low ductility. When the composition has a high ratio of brittle W, the structure of the skeleton made of W is a tight structure that is difficult to deform. Even if Cu is infiltrated into the skeleton, ductility cannot be improved. Therefore, a crack is easily generated in the skeleton due to the impact of the arc, and the generated crack is easily propagated. As a result, it can be judged that a composition in which the mass ratio of W is higher than this is likely to generate a crack due to the arc, and the electric contact is easily lost from the crack, so that it is difficult to endure use.

  Sample 8 is an example using Ag instead of Cu of sample 5. The sample using Ag as M1 was even less consumed than the sample using Cu as well.

  The comparative sample 101 is a conventional electrical contact material made only of Cu and W.

  Sample 21 to Sample 26 and Comparative Samples 131 and 132 adopted the ratio of Sample 5 that showed excellent characteristics for (A) and (B), and variously changed the amount of (C) (external mass part). Is.

Of the samples 21 to 26 and the comparative samples 131 and 132 that were tested by changing the blending ratio of (c), the sample with the lowest consumption was (c) SrB ₂ O ₄ was a sample 23 with 1.0 external mass part. there were. The comparative sample 131 with the smallest amount of (c) showed almost no effect of addition, and was almost the same as the comparative sample 101.

  The effect of the addition was clearly seen from the sample 21 in which the addition amount of (c) was 0.05 external mass part, and consumption by the arc occurred gently over almost the entire surface where the electrical contact faces. This effect shows the characteristics as the addition amount is increased up to 1.0 external part by mass. However, the comparative sample 132 exceeding 8 parts by mass has remarkably deteriorated sinterability and is difficult to manufacture. It was.

Samples 31 to 34 were subjected to a test in which the type of (c) was changed based on the sample 23 that showed particularly excellent performance as (c). The borate used as (c) is LaBO ₃ , BaB ₂ O ₄ , Mg ₃ (BO ₃ ) ₂ , and CaB ₂ O ₄ , respectively.

  By adding any of these, it is possible to suppress the consumption of the electrical contact, which is more conspicuous than that of the Cu-W material and the conventional technology, and the occurrence of cracks is also improved.

In Samples 41 to 44, part or all of the borate of (c) was replaced with boron oxide and either M3 oxide (M3 ₂ O ₃ , M3O ₂ ) or M3 carbonate (M3CO ₃ ). This is a sample. All of the samples showed almost the same consumption as when (C) was a borate and exhibited excellent characteristics.

  Samples 45 to 49 and Sample 50 are samples in which the total amount of (B) is not changed and the amount and type of the iron group metal contained in (B) are changed. From the test results, it was confirmed that the amount of the iron group metal was particularly good in the range of 0.005 to 1.0 parts by mass with respect to 100 parts by mass in total of (A) and (B). Within this range, sintering and infiltration were particularly good. Moreover, since the amount of the iron group metal that is easily evaporated by the arc is suitable, the consumption of the electrode contact with respect to the arc can be sufficiently reduced as compared with the case where the amount of the iron group metal is larger (sample 50). did it. When an alloy of M2 and an iron group metal is formed, the total of the amount of the iron group metal and the amount of the alloy of M2 and the iron group metal is 100 masses in total of (A) and (B). It is preferable to set within the range of 0.005 to 1.0 part by mass in the part.

(Example 3)
The electrical contact material of the sample 41 shown in Example 2 was used for the electrical contact 1 having a structure in which an arc is generated from multiple points, which is composed of a combination of the shape of a bar and a cup as shown in FIG.

  Also in the circuit breaker 10 of the third embodiment, the shapes of the electrical contact 1 and the shank 2 arranged in the sealed container 5 are different, but the electrical contact material is consumed similarly to the circuit breaker 10 shown in FIG. Was successfully controlled. In addition, in the circuit breaker 10 shown in FIG. 6, the mechanism 8 which pushes and pulls an electrode is connected to the circuit breaker member (the right side of a figure) of a U-shaped cross section (what is called a tulip type).

  Even in the circuit breaker having such a configuration, the electrical contact 1 according to the embodiment of the present invention is preferably used.

  The electrical contact material according to the embodiment of the present invention is suitably used in various switching devices such as an electrical circuit breaker, disconnector, and switch.

First electric contact 2 shank 3 leads 4 SF ₆ gas 5 hermetic container 6 electrical contact erosion portion 7 crack 8 push-pull mechanism 10 breaker 11 low particle electrical contact surfaces 12 arc 13 work function

Claims (7)

An electrical contact material made of a material that is used for an electrical contact and occupies 95% by mass to 100% by mass of the total mass of the following (A), (B), and (C):
(I): 5 to 50 parts by mass of M1
(B): M2 and an iron group metal element must be included, and (b) in total, 100 parts by mass of M2, an iron group metal and / or an alloy of M2 and an iron group metal (c): (a) and ( (B) 0.05 to 8 parts by mass of M3 borate and / or the composition of M3 borate with respect to 100 parts by mass of the total mass of
However,
The M1 is any one or two of Cu or Ag and an alloy thereof. The M2 is any one or two of W or Mo and an alloy thereof.
Wherein M3 is, Ca, Sr, is any one or more metals of Ba or Mg,
The constituent of the M3 borate comprises boron oxide and the M3 oxide and / or carbonate. A part or all of the M3 borate of (c) is decomposed;
Boron oxide (any one or more of B ₂ O ₃ , B ₂ O ₂ , B ₄ O ₃ .2H ₂ O, B ₄ O ₅ ),
The electrical contact material according to claim 1, wherein the electrical contact material is present in one or more of M3 oxide (M3 ₂ O ₃ , M3O ₂ ) and / or M3 carbonate (M3CO ₃ ). .   The total of the mass of the iron group metal and the mass of the alloy of M2 and the iron group metal occupies 0.005 to 1 part by mass with respect to 100 parts by mass of the total mass of (A) and (B). The electrical contact material according to claim 1 or claim 2. The borate of (c) can be expressed as M3 _a B _b O _c ,
a = 2, b = 2, c = 5
A first borate represented by
a = 1, b = 2, c = 4
The electric contact material in any one of Claims 1-3 containing either or both with the 2nd borate shown by these.   The electrical contact comprised using the electrical contact material in any one of Claims 1-4. (I): preparing 5 to 50 parts by mass of M1,
(B): a step of preparing 100 parts by mass of M2 and an iron group metal in total with (a);
(C) Prepare 0.05 to 8 parts by mass of M3 borate and / or M3 borate composition with respect to 100 parts by mass of the total mass of (A) and (B). Process,
Forming a skeleton alloy using (b) and (c);
Infiltrating the (a) into the skeleton alloy,
However,
Said M1 is any one or two of Cu or Ag and their alloys,
M2 is any one or two of W or Mo and alloys thereof.
Wherein M3 is, Ca, Sr, is any one or more metals of Ba or Mg,
The composition of the M3 borate includes a boron oxide and the M3 oxide and / or carbonate. The step of preparing (c)
Preparing the boron oxide powder and the M3 oxide or carbonate powder as a constituent of the M3 borate;
The method according to claim 6, further comprising: mixing the boron oxide powder and the M3 oxide or carbonate powder and heat-treating the powder.

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