JPS5918504A - Electric contact material - 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 The present invention relates to electrical contact materials. For more information, see Silver (
Ag), boron carbide (B10) and carbon fiber,
The present invention relates to an electrical contact material that can be suitably used for air switches such as circuit breakers.

Conventionally, Ag-WO-based or Ag-0cLO-based materials have been mainly used as electrical contact materials for air switches such as circuit breakers. There is a problem that highly insulating tungsten (W) oxide forms on the contact surface, increasing the contact resistance and increasing the temperature of the contact.
When g-QdQ type materials are used, the contact resistance is relatively stable, but there is a drawback that the breaking capacity is small due to poor fire resistance or welding resistance.

Recently 1t! There is a desire to reduce the use of precious metal Ag, which is the main component of air contact materials, and with the trend toward smaller circuit breakers and increased interrupting capacity, it is necessary to sufficiently meet the characteristics required for circuit breakers. There is an increasing need for electrical contact materials that can satisfy the following requirements.

Therefore, the inventors of the present invention have conducted extensive research to eliminate the above-mentioned drawbacks, and have found that by dispersing B4C and carbon fiber in Ag, the amount of Ag used can be reduced, and air switches such as circuit breakers can be We have completed an electrical contact material that can be made smaller and improve its performance.

That is, the electrical contact material of the present invention contains 1 to 20% B4C (
weight%, the same applies hereinafter) 0 to 10% carbon fiber and the balance is A
It is an electrical contact material consisting essentially of g.

Since B4C used in the electrical contact material of the present invention is hard (hardness 3500 kp/mm2), it increases the strength and hardness of the electrical contact and improves wear resistance. Furthermore, since the melting point (2450Oc) of B4C is high, the fire resistance of the electrical contacts is improved, and since B4C has low wettability with metals, the welding resistance of the electrical contacts is improved.

The carbon fiber used in the contact material of the present invention has low wettability with molten metal, so it improves the welding resistance of the contact and
It has a low specific resistance and is effective in preventing oxidation of the contact material even at high temperatures and reducing contact resistance. In particular, it also has the effect of preventing the oxidation of B40. Furthermore, carbon fiber is a high-strength material (tensile strength 3DD ~ 350kp/
mm2), and by dispersing it in Ag, a carbon fiber-reinforced metal is constructed, which increases the strength of the contact, and its high melting point (3700°0) improves the fire resistance of the contact.

Further, while the specific gravity of WO used as a conventional electrical contact material is 15.8, the specific gravity of B4O and carbon fiber contained in the electrical contact material of the present invention is 2.8, respectively.
5 and 1.75, the weight of the contact material can be reduced compared to conventional ones.

As described above, the electrical contact material of the present invention has E in Ag.
, O, and carbon fibers, it is a lightweight, high-strength electrical contact material with low contact resistance, excellent welding resistance, fire resistance, and abrasion resistance.

The electrical contact material of the present invention has the above-mentioned characteristics <B4O1-2
0%1 carbon fibers 0-10% and the balance being substantially more than Ag. If the B4O content is less than 1%, the resulting electrical contact material will be consumed in a large amount, and the effect of the addition will not be sufficient. Moreover, if the B4O content exceeds 20%, the contact resistance of the resulting electrical contact material increases, which is not preferable. On the other hand, if the carbon fiber content exceeds 10%, the amount of consumption of the resulting electrical contact material increases, which is not preferable.

In addition to the above-mentioned B40 and carbon fibers, other substances may be added to the electrical contact material of the present invention depending on its use and required characteristics.

Next, the electrical contact material of the present invention will be explained with reference to Examples.

Example 6 25 meshes of Ag powder, 180 meshes of B4O powder, and carbon fibers with a diameter of about 7 μm and an average fiber length of 300 μm were mixed with 93% Ag, 3.5% B4O, and 6.5% carbon fiber.
The mixed powder blended in the proportion of
A compressed body in the shape of a disk of mm was produced. The obtained compressed body was heated and sintered at a temperature of 850°a in a nitrogen gas flow. Furthermore, the sintered body was pressurized again at a pressure of 4Ton/cm2. Figure 1 shows a photograph of the cross-sectional structure observed using a scanning electron microscope of the sample of the electrical contact material of the example obtained in this way (magnification: 64
(magnification: 400x) and FIG. 2 (magnification: 400x). The composition of this example is Ag9 straw, B4O5.5%, carbon fiber 6.5%.
%Met. In addition, in Fig. 2, (1) is B4O, (
2) is carbon fiber, and (3) is matrix Ag.

As can be seen from the cross-sectional structure observation photographs shown in Figures 1 and 2,
The electrical contact material of the present invention has B4O and carbon fibers uniformly dispersed in Ag, thereby achieving the effects of the present invention of excellent wear resistance, welding resistance, and fire resistance.

The electrical contact material of the present invention can constitute an electrical contact with low contact resistance and excellent wear resistance, welding resistance, and fire resistance, and can be used in air switches such as circuit breakers. It has the excellent effect of reducing the amount of use, as well as making it possible to downsize or improve the performance of air switches such as circuit breakers, and its practical value is extremely great.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are photographs of the cross-sectional structure of the electrical contact material of the present invention obtained in Examples taken with a scanning electron microscope at magnifications of 64 times and 400 times, respectively. (Drawing codes) (1): B4O (2): Carbon fiber (II): Matrix Ag Agent: Makoto Kuzuno (and one other person) Figure 1 Figure 2 Draft procedure amendment (method) 1. Indication of the case Patent Application No. 57-129465 2, Title of the invention: Electrical contact material 3, Representative of the person making the amendment: Kata Yuhito 4, Agent 5, Date of amendment order: October 26, 1980 (shipment date) 6. Target of amendment (1) 1. Detailed explanation of the invention in the specification column (2) ``Brief explanation of the drawings'' column in the specification (8) Drawing 7, contents of amendment (1) Page 5 of the specification 8 rows of 1 photo" is corrected to ``Photo sketch diagram." (2) "Photograph" on page 5, line 16, is replaced with "photo sketch diagram"
and correct it. (3) Correct ``Photograph'' in line 8 on page 6 to read ``Sketch diagram of 1 photo.'' (4) The drawings (Figures 1 and 2) shall be corrected as shown in the attached revised drawings (Figures 1 and 2). (5) Add reference photos. 8. List of attached documents (1) Amended drawings (Figures 1 and 2)
1 copy (2) Reference photos (Reference photo A and Reference photo B)
1 tsai 1 fig.

Claims (1)

[Claims] (1) An electrical contact material consisting of 1 to 20% by weight of boron carbide, 0 to 10% by weight of carbon fibers, and the balance consisting essentially of silver.