JPS5896833A - Electric contact material - Google Patents

Abstract

PURPOSE:To provide an electrical contact material consisting of prescribed percentages of Ni and one or more among tungsten carbide, chromium carbide and molybdenum carbide, and the balance Ag, giving stabilized contact resistance, and having superior workability, welding resistance and hardly dissipative property. CONSTITUTION:This Ag-Ni type electrical contact material consists of, by weight, 5-10% Ni, 0.4-2% one or more among tungsten carbide, chromium carbide and molybdenum carbide, and the balance Ag. An electrical contact made of this electrical contact material has more stable electric resistance than a conventional electrical contact, and the conventional superior hardly dissipative property is maintained. All of tungsten carbide, chromium carbide and molybdenum carbide have very high hardness and inferior fitness to Ag and Ni, yet by uniformly dispersing >=1 kind of the carbodes in an Ag-Ni alloy, the aggregation of Ni is prevented and the contact performance is enhanced.

Description

[Detailed description of the invention] The present invention relates to electrical contact materials.

Conventionally, silver-metal oxide based, silver-nickel based, silver-tungsten based, silver-gla7ite based, etc. have been used as electrical contact materials.
Skin is widely used not only for its skin protection properties but also for its ease of processing. Conventional nickel has a weight ratio of 109! ~30% is often used. The reason for this is that it has excellent overall evaluation of contact resistance, welding resistance, and abrasion resistance, all of which are required for electrical contacts. If it is less than 10Is, it has not been used in the past because its surface performance is almost the same as that of silver, but recently mechanical parts have been miniaturized, and as a result, contact force, separation force, etc. are small, and contact resistance is high. However, if the mechanism becomes unstable, a final KFi conduction failure occurs, resulting in a problem that the mechanical parts do not operate normally. The reason for this is that silver and nickel hardly form a solid solution, so they are manufactured using a powder metallurgy method of mixing, compressing, and extruding silver powder and nickel powder. Therefore, silver powder and nickel powder are mechanically mixed and bonded, and when this material is used as an electrical contact, nickel aggregates and oxidizes due to gel heat and arc heat during opening and closing. It becomes full of nickel oxide. However, in the past, this problem could be solved by improving the mechanical parts, such as the large contact force and separation force, but as mentioned at the beginning, it became impossible to deal with this problem as the mechanical parts became smaller.

The present invention has been made in view of the above circumstances with the object of stabilizing the contact resistance of a nickel-based electrical contact material. t + The present invention provides an electrical contact material that has the advantages of silver-nickel electrical contact materials, such as good workability, good welding resistance, and abrasion resistance, and has stable contact resistance without damaging the tube. purpose.

The present invention is a bonded material characterized by comprising, in weight ratio, 5 to 109 g of nickel and at least one of tungsten carbide, chromium carbide, or molybdenum carbide in a total of 0.4 to 2-remainder chains. .

Tungsten carbide, chromium carbide or molybdenum carbide are
Both have extremely high hardness and are poorly compatible with both steel and nickel. Therefore, the present invention aims to prevent nickel agglomeration and improve contact performance by uniformly dispersing at least one of these carbides in a 1m-=Tskel alloy material.

Here, the reason why the weight of nickel is limited to StS ~ 10% is because if it is less than 59G, the welding resistance and wear resistance will deteriorate, and if it is more than 101, the agglomeration and oxidation of nickel will become severe. Also tungsten carbide.

Chromium carbide or molybdenum carbide acts uniformly on the silver-nickel alloy with a frontage of 0.4 to 29 G, and either carbide stabilizes the contact resistance without impairing welding resistance or abrasion resistance. However, if it is less than 0.45G, it will not be possible to prevent the agglomeration of nickel due to Joule heat and arc heat during the opening and closing of electrical contacts, and if it exceeds 2 G, workability will deteriorate and wear and tear during opening and closing will become significant, so the total amount of these carbides will be reduced. The amount was limited to 0.4 to 21 g.

Next, Honji F! In order to clarify the effects of electrical contact materials made of AK, specific examples and conventional examples thereof will be described.

Example 1 Silver powder, nickel powder, and tungsten carbide powder each having a grain size of several tens of microns were mixed in a weight ratio of 90:8:2.

This mixed powder was repeatedly compressed and sintered, then hot extruded and cold wire drawn. Then, by header processing, this wire has a movable w-shape with a head diameter of 2.8 wJf and a head diameter of 3.5 m.
1 fixed contact tube was obtained.

Example 2 Silver powder, nickel powder, tungsten carbide powder, and molybdenum carbide powder each having a particle size of about 100 Z chrome were mixed in a weight ratio of 94:5:0.
They were mixed at a ratio of 5:0.5. This mixed powder was used in Example 1.
A movable contact and a fixed contact were obtained in a similar manner.

Example 3 Silver powder, nickel powder, and carbonized rice powder having a particle size of 100 μm St were mixed in a weight ratio of 89.6:10:0.4. A movable contact and a fixed contact were obtained in the same manner as in Example 1 of this woodwind mixture.

Conventional example 1 Silver powder and nickel powder with a particle size of several 10 ζ chromons at a weight ratio of 90
:100 ratio. This mixed powder was repeatedly compressed and sintered, then hot extruded and cold stretched. and,
With this wire pipe header processing, the head diameter is 2. ．． 8 wa /
Movable W! A fixed II captive tube with a head diameter of 3.5 ml was obtained.

Conventional Example 2 Particle size of 100 μm S vertical Is leopard and nickel powder is 7023
They were mixed at a ratio of 0. A movable contact and a fixed *, at were obtained in the same manner as in Conventional Example 1 for this mixed powder wood pipe.

Therefore, the rivet type electric mAs of Examples 1 to 3 and Conventional Examples 1 to 2 were each tested in open/close test tubes under the test conditions of 9 sets of tubes, and the welding resistance and contact resistance of the tubes were investigated. I got Ojo.

Test condition voltage AClooV 50Hz voltage
Current 5A Opening/closing frequency 20 times/min Load Resistance Switching/closing frequency Until welding occurs As is clear from the results in the table above, the electrical contacts made with the electrical contact material of the present invention have more stable contact resistance than conventional electrical contacts. It can also be seen that the welding resistance is as excellent as that of the conventional example.

As is clear from the above description, the electrical contact material of the present invention is an epoch-making invention with superior contact resistance stability compared to conventional electrical contact materials.

Recruiter: Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (1)

[Claims] 5-10 nickel and tungsten carbide by weight,
Total of at least one of chromium carbide and molybdenum carbide
．． 4-291. An electrical contact material characterized in that the remainder consists of silver.