JPS6367536B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel electrical contact material,
In particular, in place of the Ag-CdO-based contact materials that have been widely used in the past, from relatively small current relays to large current ranges such as electromagnetic switches and circuit breakers, CdO has been eliminated and alternative oxides have been incorporated. This relates to Ag oxide-based contact materials. Conventionally, various materials have been used as electrical contact materials, but Ag-CdO materials in particular have excellent properties such as welding resistance, abrasion resistance, and contact resistance stability required for electrical contacts. Therefore, the demand for this material is increasing year by year, and the materials have been improved repeatedly, and there is also a lot of academic research regarding these materials, so it can be said that the progress of this type of materials and manufacturing technology has reached its limit. However, as is known, this Ag-CdO contact material involves many steps in its manufacturing process, such as melting, hot working, high-temperature internal oxidation, analysis, and recovery, which easily discharge Cd out of the system. Naturally, efforts must be made to prevent such emissions. As a result, especially with the expansion of production facilities, a huge amount of pollution prevention equipment will be required, and a large amount of energy will be consumed for the prevention, which will have a significant impact on production prices. Dispersing CdO in Ag is effective in improving performance such as cleaning the contact surface and reducing welding force, but this effect is particularly effective in AC circuits. However, when this contact material is used in a DC circuit where the polarity does not change, there are disadvantages such as relatively poor welding resistance and an increase in contact resistance as the number of openings and closings increases. The cause of this is proposed to be that the contact material is transferred from one pole to the other, forming a deteriorated layer on the contact surface that is different from the contact base material.
It can be said that this is a fate that cannot be overcome as long as Ag-CdO type contacts are used. Therefore, the development of new materials comparable to Ag-CdO-based contact materials has attracted attention, and various studies have been conducted in recent years, and electrical contact materials containing dispersed La oxides in Ag have also been announced. . Therefore, in view of the above points, the applicant has already
As a result of repeated research on the role of oxides that do not contain components in contributing to contact characteristics, we have found that the cleaning effect on the surface of electrical contacts and various phenomena against arcs, such as arc-extinguishing effects, are important for the physical properties of added oxides, especially their We came up with the idea that vapor pressure is most closely related to temperature characteristics, and obtained the guidelines necessary for the development of high-performance Ag-oxide contact materials. Based on this thinking, we focused on oxides with vapor pressures close to that of CdO, including Sb, Mn, Sn, In,
We were able to confirm that by incorporating oxides such as Te into Ag, it was possible to exhibit a contact surface cleaning effect equivalent to or greater than that of Ag-CdO type contacts. Furthermore, various proposals have been announced regarding the possibility of synergistic effects by adding Ni, Fe, etc. The present invention was made based on the research progress described above, and consists of an oxide of Sb, which has a vapor pressure higher than that of CdO in the temperature range of about 500 to 1500°C, in Ag.
Sn oxide with higher vapor pressure than CdO in the temperature range of 1500-4000℃, CdO in the temperature range of about 500-4000℃
By combining and dispersing In and Mn oxides, which have lower vapor pressures, it is possible to exhibit excellent contact characteristics. Furthermore, an important point of the present invention is that by dispersing an oxide in which Te is added to the above elements,
The goal is to improve defects such as those found in Ag-CdO contacts. In other words, as is known, with frequent operation of equipment,
In the case of a switch that controls opening and closing, the contact surface is heated to a high enough temperature that it melts due to arc heat or joule heat, and this temperature drops to room temperature when the operation is stopped at night, etc. The thermal cycle will be repeated. By the way, the contact has Cu layer with Ag layer on one side,
Although it will be brazed to a base material such as Cu-Zn, there is a difference in the thermal expansion coefficient of Ag, the base material mentioned above, and the contact material (Ag-CdO), so the frequent thermal cycles as described above are required. When expansion and contraction are repeated,
A phenomenon occurs in which the contact point is curved and deformed, and this causes the contact point to peel off from the base material, causing the peeled part to be lost, worn out, or to rise in temperature. The addition of Te described above has the effect of uniformly and finely dispersing the oxide in Ag, thereby reducing the exfoliation and consumption phenomenon. Therefore, invention (1) is 0.2 to 6.2 wt% Sb, 0.1 to 2.0 wt% Mn, 0.5 to 5.0 wt% Sn, 0.1 to 5.0 wt% In,
0.01 to 1.2 wt% Te, and the total is 5.0 to 15.0
It is characterized in that elemental components within a range of % by weight are dispersed as oxides, with the balance being Ag. As is known, there are sintering methods (powder metallurgy) and internal oxidation methods for manufacturing such electrical contact materials, but the latter is often used because internal oxidation has better wear resistance. ing. The manufacturing method of internally oxidized alloy contacts includes Ag, Sb, Su,
By melting an Ag-based alloy with In, Mn, and Te and keeping it at high temperature in an oxygen atmosphere, oxygen enters from the surface of the alloy and selectively oxidizes the added elements. Uniformly and finely dispersed as an oxide in Ag. Sb as a component element must be 0.2 to 6.2% by weight, and the upper limit of the amount of Sb added to Ag is 6.2% by weight.
The reason why it has to be limited to % by weight is that the maximum solid solubility limit of Sb in the alpha solid solution of the alloy is 6.2% at 300°C.
% by weight, and if Sb is added in an amount exceeding this amount, cold workability will be significantly inhibited, making mass production of electrical contact materials difficult. On the other hand, if the amount added is less than 0.2% by weight, no significant addition effect will be obtained and the purpose will not be achieved. When Mn is further added, Mn oxide becomes approximately 2000
Since it has a lower vapor pressure than Sb and Sn oxides at high temperatures of ℃ or higher, it has the effect of suppressing volatilization loss due to arcing of these oxides. The reason for setting the upper limit of Mn addition to 2.0% by weight is that adding Mn has the effect of suppressing the precipitation of oxides at grain boundaries, but as mentioned above,
When the upper limit of 2.0% by weight is exceeded, this tendency appears,
As the oxide dispersion becomes thinner near the grain boundaries,
This is because it will have an adverse effect on the contact characteristics, and the lower limit of 0.1% by weight represents the minimum level of effectiveness. Sn as a constituent element must be in the range 0.5-5.0% by weight. The reason why it is necessary to limit this range is that when an alloy containing Sn is internally oxidized, the oxide takes on a acicular shape, but when more than 5.0% by weight is added, the oxide forms a layer near the surface. This is because the internal oxidation treatment becomes difficult because Sn is formed in the Sn content, and on the other hand, if the Sn content is less than 0.5% by weight, the effect of adding Sn will not be apparent. Alloys containing In, like Sn, undergo internal oxidation.
It becomes an acicular oxide, but if In is added in excess of 5.0% by weight in an alloy that is combined with Sb or other elements, a dense oxide film will be formed on the surface during internal oxidation, and this will cause the internal Since this makes oxidation difficult, the upper limit must be set at 5.0% by weight.
If the amount is less than 0.1% by weight, the effect of addition will not be clear. In the present invention, Te is further added as described above, and the effect of the addition is to reduce thermal distortion due to thermal cycles as described above, and to eliminate peeling and abnormal wear of contacts. The reason why the upper limit was set at 1.2% by weight is that an intermetallic compound of Te and Ag is formed in the melted sample, resulting in decreased workability, and processing becomes difficult when Te is added in an amount of 1.2% by weight or more. be. The lower limit of 0.01% by weight indicates the minimum level of effectiveness. In this way, by adding Sb, Mn, Sn, In, and Te in combination, a synergistic effect that cannot be obtained by adding them alone can be obtained, and excellent contact performance can be achieved. Furthermore, if the total amount of additional element components exceeds 15.0% by weight, it becomes extremely difficult to uniformly and finely disperse the oxide by internal oxidation. On the other hand, when the total amount is less than 5.0% by weight, the effect on improving contact performance is not clearly apparent. Next, in invention (2), in addition to the content of the invention in (1) above, one or two types of Ni with a metal component of 0.01 to 0.5% by weight and Fe with a metal component of 0.01 to 1.0% by weight are provided. oxide is also dispersed therein, with the remainder being Ag. Here, the role of adding Ni and Fe as mentioned above is to refine and organize the oxide particles, and in this case, the upper limit of 0.5% by weight as mentioned above is because if added in excess of this, it will dissolve. This is because it becomes difficult to obtain a uniform alloy. Further, the lower limit of 0.01% by weight means the minimum amount at which the above-mentioned effect of making the oxide particles finer can be exhibited. Furthermore, if the total amount of added components exceeds 15.0% by weight, it becomes extremely difficult to uniformly and finely disperse the oxide by internal oxidation. On the other hand, if the total amount is less than 5.0% by weight, the effect on improving contact performance will not clearly appear. Here, if we show an example of invention (1), 99.5
(1) Ag−1.5Sb−1.0Mn−3.0Sn−3.0In−0.5Te by using component materials with a purity of at least % by weight as raw materials and dissolving them in the air.
(Total 8.7) (2) Ag−1.0Sb−1.5Mn−4.0Sn−3.0In−0.8Te
(Total 10.3) (3) Ag−3.0Sb−1.0Mn−1.5Sn−2.0In−0.6Te
(total 8.1) (4) Ag−0.23Sb−0.5Sn−2.0In−0.01Te (total
7.74) (5) Ag−6.0Sb−2.0Mn−2.0Sn−4.0In−0.05Te
(Total 14.05) (6) Ag−4.0Sb−0.2Mn−2.0Sn−0.1In−1.2Te
(Total: 7.5) An ingot is produced, the surface layer of this ingot is milled, and a thin pure silver plate is thermocompression bonded to one surface to form a silver layer for brazing. Next, the material was cold-rolled into a plate with a thickness of 2 mm, and then punched into a disk shape with a diameter of 8 mm using a press machine. This was placed in an internal oxidation furnace and heated at 750°C while introducing oxygen into the furnace. Heating for 180 hours, Sb, In,
The alloy of the present invention was produced by oxidizing Mn and Te. Further, as an example of invention (2), the above invention (1)
(7) Ag−2.0Sb−1.5Mn−3.0Sn−2.5In−0.3Te−
0.3Ni (total 9.6) (8) Ag−5.0Sb−1.0Mn−2.0Sn−1.0In−0.3Te−
0.3Fe (total 9.6) (9) Ag−1.5Sb−1.0Mn−4.0Sn−3.0In−0.3Te−
0.2Ni−0.2Fe (total 10.2) (10) Ag−0.3Sb−0.1Mn−4.0Sn−0.5In−0.2Te−
0.05Ni (total 5.15) (11) Ag−0.5Sb−0.1Mn−0.5Sn−5.0In−0.1Te−
An alloy of the present invention was made of 0.49Ni−0.01Fe (total 6.7). For the above (1) to (11), the Ag layer formed on the back side of the alloy and the base material for holding the contact were brazed with Ag and used as a sample for the contact test.
Using ASTM contact tester, voltage AC100V, current
Tests were conducted on each item listed in Table 1 under the conditions of 20A, power factor 0.6, contact force 150g, and release force 300g, while comparing with typical contact materials used in the past.

【table】

[Table] Ag
-Compared to CdO-based contacts, the amount of wear can be considerably reduced, and the number of welds can be significantly reduced, and there is also an improvement in the wear and peeling caused by thermal cycling mentioned above. By adding Ni and Fe, we were able to arrange the oxide particles and promote improvement in the number of welds.

Claims (1)

[Claims] 1 0.2-6.2% by weight Sb, 0.1-2.0% by weight Mn, 0.5
~5.0 wt% Sn, 0.1~5.0 wt% In, 0.01~1.2 wt% Te, and the elemental components in the range of 5.0~15.0 wt% in total are dispersed as oxides, and the balance is Ag. A silver-oxide contact material characterized by: 2 0.2-6.2 wt% Sb, 0.1-2.0 wt% Mn, 0.5
~5.0wt% Sn, 0.1~5.0wt% In, 0.01~1.2wt% Te, and one or both of 0.01~0.5wt% Ni and 0.01~0.5wt% Fe are added to give a total of 5.0~15.0wt% A silver-oxide contact material characterized in that elemental components in a range of % by weight are dispersed as oxides, with the balance being Ag.