JPS59114715A - Method of producing contactor for vacuum breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a contactor for a vacuum circuit breaker.

[Technical background of the invention and its problems]

There are three main conditions required for the contacts of vacuum circuit breakers: breaking characteristics, withstand voltage characteristics, and anti-welding characteristics.Cu-Bi (copper-bismuth), contact materials that almost satisfy these conditions are Cu-Te (copper-tellurium), Cu-S
b (copper-antimony), Cu-Se (copper-selenium), and Cu-Pb (copper-lead) alloys are known.

By the way, since these alloys generally have brittle properties, they are difficult to process and form because they tend to crack or chip during the commonly used cold working.

Therefore, it has been common practice to make a round bar in advance by casting and then cut it to make a contact.

However, with this method, a large amount of expensive contact material is cut (cut and discarded), which poses a problem from an economic point of view.Furthermore, contacts made only by casting generally have rough braided wires and a distribution of precipitates. Also, depending on the casting method, the molten metal may solidify during pouring, making it difficult for the molten metal to circulate properly, or causing cavities to form inside the circuit breaker. Bi%Te%sb%3e, Pb has a high vapor pressure, so it is easy for bubbles to form in the molded mass (particularly when casting into a small diameter sprue). There are drawbacks such as the tendency for air bubbles to form near the surface when filling the surface.

Moreover, since there are many different shapes and dimensions of contacts depending on their ratings, increasing the cutting yield requires the use of numerous molds, all of which have drawbacks that lead to increased costs and reduced yields. It has been pointed out.

In order to eliminate these drawbacks, a method of manufacturing contact materials has been attempted in which the initial forging processing rate is 10 to 15% at a temperature of 750-800°C, and the processing rate is gradually increased thereafter. ing. According to this manufacturing method, it is possible to obtain a contact material with a uniform distribution and shape of precipitates.

On the other hand, in recent years, with the increase in the withstand voltage and current of vacuum circuit breakers, it has become necessary to use high-quality contact materials with large diameters (for example, diameter 15C+A) and with less impurities and gases. . However, depending on the forging method described above, gas may enter from the surface through the cracks that occur on the surface of the brittle contact material, and foreign substances such as oxides may be deposited or entrapped in the cracks. Not necessarily sufficient to manufacture contact materials;
Therefore, the surface layer must be removed, and the loss of expensive contact material increases as the diameter increases.

600-8 as a technology to improve the drawbacks of the dual-speed forging method.
Although hot rolling processing at 00°C is considered,
Similarly, a certain amount of the contact material on the surface is also removed due to the diffusion of gas from the surface and the intrusion of foreign matter, which is not necessarily satisfactory in terms of both productivity and economy.

[Purpose of the invention]

The present invention has been made in consideration of these circumstances, and its purpose is to provide a method for manufacturing a contact for a vacuum circuit breaker that has stable contact characteristics and is also economically efficient. [Summary of the Invention] In order to achieve the above object, the present invention provides a contact material made of Cu as a base material and containing at least one of Bi, Te, PB, and Bb. (Both sides have Cu that does not contain Bi, Te, Pb, or Sb.)
The first step is to overlay a protective layer with a thickness of 1 to 300 ℃, consisting of Ni, Ni, or SuS, and then heat the overlaid contact material and protective layer to a temperature of 400 to 1000°C to separate the contact material and the protective layer. a second step of metallurgically adhering the contact material and the protective layer to a softened state, and a third step of pressurizing and integrating the softened contact material and the protective layer by at least one of forging and rolling; The present invention is characterized by comprising a fourth step of removing at least one side of the protective layer from the contact material and the protective layer, and exposing the contact material to obtain a contact surface.

The second step and the third step may be repeated multiple times in combination.

When providing a protective layer on both sides of the contact material, remove one protective layer to expose the contact material as a contact surface, leave part or all of the other protective layer, and remove the silver plated layer. can do.

It is preferable to interpose a thin layer of Ag, In, or Sn with a thickness of 100 μm or less between the contact material and the protective layer. The reason for this will be explained later.

[Detailed Description of the Invention] CU is used as a base material, and Bi, Te, Pb, and Sb are added to the base material.
Alloys for contact materials containing such materials are extremely brittle, and are usually difficult to process into plates due to the concentration of brittle precipitates at grain boundaries.

Only a small amount of processing can be performed on Cu-Te alloys under strictly controlled conditions.

Conventional methods used to process these alloys, including Bi, Pb, and Sb, in which a hammer or roll directly touched the contact material.
In addition to the fact that cracks are likely to occur in the contact material, especially at the edges, even if the surface layer of the contact material is cut off to remove oxides generated by heating, foreign particles may get inside the material during forging or rolling. This has an unfavorable effect on the withstand voltage characteristics of the vacuum circuit breaker, such as allowing the gas to get mixed in and also causing the gas to diffuse into the inside of the capacitor through the cracks. As mentioned above, when we investigated the behavior of the released gas when the contact material obtained by directly touching the contact material with a processing hammer or roll according to the conventional method was heated from room temperature to melting, it was found that 400. ~50
Significant release of water (H2O) at 0°C may be observed or detected in some materials. It has been observed that such materials still release oxygen-based gases even after bath melting. This suggests that a large amount of water is adsorbed in cracks formed inside and on the surface of the contact material, and the negative effect on the basic properties of the contact cannot be ignored. Moreover, it is considered that the contact element side is one of the causes of blistering of the contact during silver soldering and other heating processes included in the vacuum pulp assembly process. Some of the problems mentioned above can be alleviated to some extent by conventional methods under strict process control, but it is not necessarily efficient and requires a large amount of contact material (which is the initial trigger of the problem). This suggests that it is fundamental to reduce cracks.Based on this suggestion, the present inventors
Cu is added to the contact material to prevent cracks from occurring on the surface or end surface of the contact material during processing.

By providing a protective layer made of Ni1 or SuS, and combining the excellent ductility of the protective layer with specified process control, we have developed a contact stack made of a Cu alloy containing Bi, Te, pb, and Sb, which was previously considered impossible. This enabled efficient processing of the moon.

Hereinafter, the manufacturing method of the present invention will be explained with reference to the drawings.

FIG. 1 shows a contactor (1,717 people) before implementing the present invention. Here, as a component, Cu is used as a base material, and at least one of Bi, Te, Pb, and 8b is used as a base material. A contact material IO containing Bi is disposed on both upper and lower surfaces of the contact material IO.

A protective layer blade and a protective layer made of Cu, Ni, or SuS that do not contain Te, Pb, or Sb are provided.

The upper and lower surfaces of the contact material 10 are represented by 11 and 12, the lower surface of the protective layer blade is represented by 21, and the upper and lower surfaces of the protective layer (G) are represented by 31° and 32. Ho 88213.30 is
As already mentioned (the upper and lower surfaces 11, 1 of the contact material 10
It is used to protect the contact material 10 from cracks and to prevent the entrainment of gas or foreign matter inside the contact material 10, thereby preventing deterioration of the contact material 10. A certain material is selected.

The lower surface 32 of the protective layer blade is a surface to be silver soldered if necessary, and by applying the needle 5 to the protective M Wi 30, the bonding performance is reduced due to the diffusion of the silver solder component into the contact material. It is also effective from the standpoint of prevention.

Bi%Te contained in the contact material used here.

PB and Bb are materials that have the function of improving welding resistance as contact materials for vacuum circuit breakers, and incorporating them into a Cu base material is a well-known technique, for example, as disclosed in Japanese Patent Publication No. 12131/1983.

In the present invention, the total content of n1%Te and pb%sb is selected within the range of 10 to 0.1% by weight. The reason is that if this content exceeds 10%, the effect of the contact material will not be exhibited no matter how much you adjust the integration pressurization (third step) conditions described below, and cracks will occur or continuous integration will occur. This is because a healthy contact cannot be obtained, such as not being able to bond and become granular, and if it is less than 0.1%, the welding resistance will be insufficient.

The thickness of the protective layer blade, 30, requires at least 1 inch.

Point 5 is that if it is less than 111111, cracks may occur in the protective layer for some reason during the integration pressurization step (third step), which will be described later, or the protective layer may be worn out due to the formation of oxides. This is because it may not be able to fully function as a protective layer, and as a result, it becomes difficult to obtain a healthy contact.

The surfaces of the contact material IO and the insulation layers 20 and 30 must be cleaned to the extent that they have been surface-treated by heat treatment or pickling treatment in a non-oxidizing atmosphere. .

Figure 2 shows a protective layer blade placed on contact material IO.
The upper surface 11 and the lower surface 21 of the protective layer blade are stacked so that they face each other, and similarly the protective layer blade is placed on the lower surface side of the contact material 1O so that the lower surface 12 of the contact material 1O and the upper surface 31 of the protective layer blade are opposed to each other. This figure shows the state in which the first step of superimposing the two images has been completed. While stacked in this way, as a second step, the contact material 1 is heated to a temperature between 400 and 1000°C.
0 and the protective layers above and below it.

It is brought into close metallurgical contact with Shu and made into a softened state. Here, metallurgical adhesion has the meaning of preventing or suppressing the formation of a contamination film or the adhesion of foreign matter to the contact interface.

If the heating temperature is lower than 400°C in this second step, the contact material itself has almost no ductility, resulting in a lumpy button despite the presence of a retaining layer with greater ductility, resulting in a continuous band. Furthermore, when the temperature exceeds 1000°C, it approaches the melting point of Cu, and slight fluctuations such as variations in the temperature control technology of the heating furnace and the true temperature of the shipwreck heating element can cause the heated body to locally become Cu. The temperature may reach above the melting point of , and the quality may become unstable.This is the reason why the temperature is set at 400 to 1000'C in the second step.

Thereafter, the contact material 10 and the protective layer 30 are pressed and integrated at the heating temperature of the previous step by forging, rolling, or a combination of both. This step is the third step,
FIG. 3 shows the state after this process is completed. In connection with FIG. 1, it was mentioned that the surfaces of the contact material IO and the protective layer side 30 should be kept clean. layer side,
This is because kerfs 1 to 7 are deposited at the contact interface with the contact material IO and the protective layers 2D and 30 due to the decomposition of the contaminants, and this becomes a resistive substance that obstructs the integration of the contact material IO and the protective layers 2D and 30. Another reason is that after completing the integration pressure, if one of the protective layers is cut and removed as described below, and the other protective layer is used as a bonding layer for brazing, sufficient integration pressure strength is required. This is necessary, but if the contact interface is contaminated, sufficient pressure strength cannot be obtained in many cases during pressurization.

Next, in the fourth step, at least a portion of one of the protective layers is cut and removed until the contact material 10 is exposed, forming a contact surface 13 as a contact, and forming a contact 8 as shown in FIG. complete.

In addition, in order to ensure metallurgical adhesion between the contact material and the protective layer through each step after the first step, the fifth step is performed.
As shown in the figure, it is an effective means to previously insert a bonding auxiliary layer 40 made of Ag, In, or Sn and having a thickness of 100 μm or less between the contact material 10 and the protective layer side. This is because by arranging the bonding auxiliary layer 40 in the first process step, metallurgical adhesion between the contact material IO and the protective layer side via the bonding auxiliary layer 40 can be achieved in a shorter time and more reliably. This is because it is effective in quickly avoiding gas intrusion, foreign matter contamination, and oxide film formation in subsequent steps. Bonding auxiliary layer 40
Since the Ag%In and Sn used as the Cu-based contact material 10 diffuse at an extremely high rate, there is a high possibility that they will be present on the contact surface when the contact is completed, and as a result, It has undesirable effects such as having a negative effect on the contact characteristics as a contact for a vacuum circuit breaker, lowering the bath melting point of the contact material, increasing electrical resistance in the case of In and Sn, and increasing the amount of brittle compounds produced. The bonding auxiliary layer 4o slides in proportion to the amount of the interposed bonding auxiliary layer 4o. In order to eliminate or suppress such defects, the thickness of the bonding auxiliary layer 40 is limited to 100 μm. Instead of inserting the bonding auxiliary layer 40 in the form of a plate, the same effect can be obtained by attaching it to the contact material, the insulation layer, or the opposing surfaces of both by plating or other means. can get.

On the protective layer side 30 used in the present invention, Bi, 're, pb, Sn contained in the contact material IO
I have already mentioned that it is not included. The reason for this is that in order to qualitatively install a Cu-based contact material, the protective layer must have more ductility than the contact material, but the above-mentioned components make the protective layer extremely brittle. This is because the layer becomes unable to function as a protective layer.

[Examples and comparative examples of the invention]

Example 1 (Table 1) Approximately 5 X 10” To, rr in a Kazen crucible
, Cu melted at a temperature of 1200°C was heated to 150 To
The pressure was increased to rr and Te was added. The mixture was evacuated again and cast into a cast iron mold to obtain a 2.9% Te--Cu alloy 50 KF with a diameter of 75 mm. A contact material having a thickness of 251111°, a width of 5Q + u, and a length of 70° was prepared from a part of the obtained ingot. The surface was cleaned by repeating the process of immersing it in a nitric acid □□□% aqueous solution for 10 seconds several times. Acid-free copper with a thickness of 10 mm, a width of 55 mm, and a length of 70 cIIL was heated in advance in hydrogen at 700°C, and subjected to a treatment that also served as a surface cleaning and confirmation of the presence or absence of blisters. After superimposing it on the contact material, it was heated to 800°C in hydrogen to bring them into close contact, and then taken out of the heating furnace and immediately reduced in thickness by 1.
By applying about 0% forging, a pressurized body with a thickness of 4Q mm, a width of 50 m, and a length of 4 mm was obtained. A portion was cut out and the interface was examined under a microscope, but the interface was completely integrated and no foreign matter was visible. Also, the thickness at this time is
The contact material is 23cm, Cu is on the top as a retention layer, and the bottom surface is concentrated 9
It was 1.

Heating in hydrogen and forging to about 5 to 15% were repeated several times, resulting in a thickness of 2L51111. Width: 50 fins, height: approx. 100 cI
An IL pressurized body was obtained. A portion was cut out and the interface was examined under a microscope, but no foreign matter was found and the integrity of the interface was maintained. Also, the thickness of the contact material at this time is approximately 19
The upper and lower surfaces of the Cu retention layer had an aggregate of 5.5 degrees.

It was heated again in a hydrogen furnace at 800°C, then rolled in a hot rolling mill with a roll diameter of 45 mm, and rolled several times while being heated so that the temperature of the rolled body did not fall below 600°C, resulting in a thickness of 81 m. (The thickness of the contact material is about 5mm, the thickness of the Cu protective layer,
Upper and lower surfaces combined 1.5i+m), width 501II+1 length approx. 3
．． A rolled body of 7 m was obtained. A section was cut out from the same shuttle and the cross section was examined under a microscope, but there was no foreign matter mixed in, and the integrity of the interface was maintained. Next, the upper Cu retention film layer was removed by cutting to expose the contact material, and the # remained as it was on the contact surface and the Cu retention layer on the upper and lower surfaces to form a silver soldering layer.

A contact piece with a diameter of 3Qsn and a thickness of 3.8111 was made from the contact material thus obtained, and it was attached to an assembled vacuum valve, and restriking occurred when a 6kV x 500A circuit was interrupted 2000 times. We investigated the frequency. The results are shown in Table 1. The numerical values are shown as the maximum and minimum variation widths of two circuit breakers (six as Norzo).

As is clear from Table 1, a circuit breaker using a contact made by the method of the present invention with a Cu protective layer and made under predetermined conditions has more cracks (
It is good because there are few cracks), especially the amount of gas is small, and the occurrence of restriking is extremely small. Although the technology for effectively preventing the restriking phenomenon has not yet been clarified, it is thought that the constituent materials of the electrodes and shields, the design technology, or the contact materials are mainly involved. For contacts, the main factors are processability, such as material composition related to material fragility, surface condition, and impurities. Particularly in contact alloys that contain auxiliary components such as Bi, Te, PB, and SB, which make the alloy itself brittle, the quality of processing (presence or absence of minute cracks that occur during processing of the contact) is determined by reuse. This is considered to be an important factor for the ignition phenomenon, and it is presumed that there is some correlation as shown in the examples.

Comparative Example 1 (Table 1) The contact was manufactured under almost the same conditions as in Example 1, except that the Cu protective layer was not used. That is, the remaining material of Example 1, 2.9% Te-Cu, was used as the contact material, and the thickness was 25 mm thick and 5011 m wide.

The length was 70 cIIL under the same conditions as in Example 1. After removing surface scale by pickling,
The 2.9% Te--Cu contact material heated to 0.degree. C. was subjected to the same processing rate as in Example 1 by forging to obtain a pressurized body having a thickness of 40 mm, a width of 5 Q m, and a length of about 80 crIL. However, the pressurizing body has a width of approximately 51 mm at both ends from the end surface.
In addition to numerous cracks occurring in the surface layer, there were also some cracks in the direction of the surface layer. A part of this was cut out and its interface was examined under a microscope, but the cross section showed crack growth and cracks in the surface layer. Therefore, before the next processing step, the end faces were cut off and the cracks in the surface layer were removed. Therefore, about 20% material loss occurred in this process (zero in Example 1). Note that the interface was almost normal.

Heating in hydrogen again and forging at a rate of 5 to 15% is applied until the thickness is approximately 3011 mm, and the width is approximately 50 mm! Shoulder, length 80cW
A pressure body of L was obtained. However, the pressurizing body did not form a single band of 8 oca, but was divided into two. Further width 501
At both ends of +11, numerous cracks of about 511I+ were generated from the end faces, and cracks were also generated in the surface layer in the length direction. A portion of this was cut out and the interface was examined under a microscope, but it was found that microcracks had occurred in the cross section and foreign matter had gotten stuck in the cracks in the surface layer. Therefore, the end faces were cut off and the surface cracks were removed before the next rolling process with the hot rolled material, resulting in further material loss.

Heated again in a hydrogen furnace at 800°C and made a roll with a diameter of 45 am.
A rolled product having a thickness of about 8111 mm, a width of 50 mm, and a length of about 1.2 m (total of the length since it was cut at several locations) was obtained by repeating heating and processing using a hot rolling mill. A portion was cut out in the same manner as in Example 1, and the cross section was examined under a microscope. It was found that microcracks had occurred in the cross section and foreign matter had gotten stuck in the cracks in the surface layer. Therefore, when processing the contact, it was necessary to cut off the end face.

From the contact material obtained in this way, a diameter of 30111+
.

A contact piece with a thickness of 3.811Ig was made, attached to a prefabricated vacuum knob, and a 6kV x 500A circuit was connected to the
We investigated the frequency of re-ignition when the engine was shut off. The results are also listed in Table 1. As is clear from Table 1, compared to Example 1, there were more cracks and more gas (and more restriking occurred).

In Example 1 and Comparative Example 1, which gave almost the same processing rate,
Comparing the material utilization rates of the contact materials, it is found that although the starting materials in both cases are approximately the same size (thickness 25111, width 50 mm, length 70 crIL), in Example 1 the thickness was 5 mm (Cu protection 81111 (including layers), Hakkanto,
In contrast, only Comparative Example 1, which had a length of 3.4 m, a width of 501 m, and a length of about 0.8 m, was obtained. In Example 1, the utilization rate is approximately 97%, whereas in Comparative Example 1, the utilization rate is 37%.

Moreover, in order to obtain the predetermined contact thickness of 3.8111, Example 1
In this case, the thickness of the Cu protective layer was removed (and the contact layer could be sufficiently cut out from the 5th layer, but in Comparative Example 1, the part from which these were removed was included due to the fear of cracks or other defects in the surface layer etc. described above). and 8m11 are mandatory committees.

In addition to excellent restriking characteristics as shown in Example 1 and Comparative Example 1, the method of the present invention also achieves a significant saving in expensive contact materials.

Examples 2-3; Comparative Examples 2-3 (Table 2) When the thickness of the Cu protective layer was Q, 5 myr, it broke during processing and the internal contact material could not be kept sufficiently warm (Comparative Example 2) An increase in the frequency of restriking and the amount of gas was observed. On the surface, inclusion of oxide was observed mainly around the broken Cu image 1-, and the thickness was not preferable. at least l, 0+
Use a+ (actual 'JX+i example 2).

On the other hand, if heating after adhesion is carried out at 490°C, the Cu protective layer will break and the whole will fall apart into particles, which is not preferable (Comparative Example 3), but if it is heated at 600°C, it will be sufficiently continuous and integrated (Example 3), Examples 4 to 11 of gas to contact material; Comparative Examples 4 to 5 (Tables 3 to 5) Contact material 10 and Cu protective layer added, 3
0 as shown in FIG.
0 and processed under the same conditions as in Example 3.

In this case, there is a gap between the contact material 10 and the protective layer I.
G is not included. When the cross section after processing is observed under a microscope, A
A large amount of g reached the interface 4 between the contact material 10 and the film retaining layer blade, resulting in the presence of Ag on the contact surface.

When the predetermined incidence rate of restriking was investigated, it was found that it occurs with a high probability. When Ag moves inside the contact, T
e was moved to the contact surface together with the agglomeration of Ag and Te aggregation (Comparative Example 4). This is thought to be the main reason for the increased rate of restriking, and it is necessary to limit the amount of metal in the bonding auxiliary layer 40 interposed between the contact material 10 and the protective layer 20, and the limit is considered to be about 100 μm ( Example 4).

If it is within 100 ttm, the above-mentioned build-up of the bonding auxiliary metal to the interface and the concomitant aggregation of the welding prevention metal Te will have no effect on the occurrence of restriking. Bonding auxiliary layer 40
The metal may not only be Ag (In (Example 5) or Sn (Example 6)).The insertion of these bonding auxiliary layers ensures the superposition of the contact material and the Cu protective layer and improves reliability. As a result, it contributes to preventing material deterioration of the contact material during initial processing (e.g. gas infiltration).Adding a protective layer.

As for shame, it is recognized that N, i, and SuS are sufficiently effective instead of Cu (Examples 8 to 9, Comparative Example 5)
).

Note that the protective layer is not only arranged and brought into close contact with the upper and lower surfaces of the contact material, but may also be arranged on the sides thereof so as to surround the entire outer surface (also, if the contact material is cylindrical,
Even if the outer surface is surrounded by a cylindrical protective layer and brought into close contact with it, the same effect can be obtained if the processing method under the predetermined conditions is adopted (Example 10111).

The protective layer used in the present invention does not need to be made of a single material (it is not necessary to use a separate pre-composite material, for example, the upper layer is made of Cu).

A similar effect can be obtained by using a composite material in which the lower layer is made of SuS.

〔Effect of the invention〕

As detailed above, according to the present invention, 81%Te1pb
When processing a Cu-based vacuum circuit breaker contact material containing at least one of the be able to.

[Brief explanation of the drawing]

1 to 3 are diagrams for explaining the present invention in detail, in which FIG. 1 is a sectional view of the contact material and the protective layer before the first step, and FIG. 2 is a cross-sectional view of the contact material and the protective layer after the first step. Figure 3 is a cross-sectional view of the state after the third step, Figure 4 is a cross-sectional view showing an example of a contact structure different from the contacts in Figures 1 to 3, Figure 5 is a contact FIG. 3 is a cross-sectional view showing a state in which a bonding auxiliary layer is inserted between the material and the protective layer. 10...Contact material, 20.30...Protective layer, 40.
...bonding auxiliary layer.

Claims (1)

[Claims] 1. Cu is the base material, and Bi, Te, Pb,
Bi%Te, pb, sb on at least one side of the contact material containing at least one of Sb.
a first step of overlapping a protective layer of at least in+ thickness made of Cu, Ni, or SuS containing no
A second step of heating the contact material and the protective layer to a temperature of °C to metallurgically adhere the contact material and the protective layer and softening the contact material, and pressing the softened contact material and the protective layer by at least one of forging and rolling. a third step of integrating; and a fourth step of removing at least one side of the protective layer from the integrated contact material and protective layer to expose the contact material to obtain a contact surface. A method for manufacturing a contact for a vacuum circuit breaker. 2. Cu is the base material, and Bi, Te, Pb,
A contact material containing at least one of Sb, and Cu containing no Bi, Te, Pb, or Sb.
A first step of preparing a protective layer of at least one thickness of Ni, Ni, or SuS, and superimposing the contact material and the protective layer after surface cleaning with hydrogen or acid; and the superimposed contact material and protection. 400-1000 layers
A second step of heating the contact material and the protective layer to a temperature of °C to metallurgically adhere the contact material and the protective layer and softening the contact material, and pressing the softened contact material and the protective layer by at least one of forging and rolling. a third step of integrating; and a fourth step of removing at least one side of the protective layer from the integrated contact material and protective layer to expose the contact material to obtain a contact surface. A method for manufacturing a contact for a vacuum circuit breaker. 3. Cu is used as a base material, and Bi%Te, Pb%S are added to it.
A contact material containing at least one of b.
Cu, Ni that does not contain Bi, Te, Pb, Sb
. A first step of preparing a protective layer having a thickness of at least one layer made of or SuS, and after surface cleaning the contact material and the protective layer with hydrogen or acid, overlaying protective layers on both sides of the contact material, respectively; A second step of heating the combined contact material and protective layer to a temperature of 400 to 1000°C to bring the contact material and protective layer into metallurgical tight contact and softening, and at least one of forging and rolling. a third step of pressurizing and integrating the softened contact material and protective layer; removing only one protective layer from the integrated contact material and protective layer to expose the contact material as a contact surface; A method for manufacturing a contact for a vacuum circuit breaker, comprising a fourth step of leaving part or all of the other protective layer to serve as a layer for improving silver grating properties. 4. Cu is the base material, and Ni, Te, PB,
A contact material containing a small amount of sb and a Cu%N containing no Bi, Te, Pb, or Sb.
i. or a first step of laminating a protective layer made of SuS with a thickness of 11I through a bonding auxiliary layer of 100 μm or less made of Ag, In, or Sn; 400~1000
A second step of heating the contact material and the protective layer to a temperature of °C to bring them into metallurgical contact and softening the contact material, and pressing the softened contact material and the protective layer by at least one of forging and rolling. a third step of integrating; and a fourth step of removing at least one side of the protective layer from the integrated contact material and protective layer to expose the contact material to obtain a contact surface. A method for manufacturing a contact for a vacuum circuit breaker.