JPS59219440A - Electrical contact material - Google Patents

Abstract

PURPOSE:To obtain an electrical contact material having a stable contact resistance value as well as superior resistance to welding, arc and consumption by adding specified amounts of Sn, Cu and Bi to an Ag-CdO type electrical contact material, further adding an Fe group metal as required, and carrying out internal oxidation. CONSTITUTION:Fine grains having a composition consisting of, by weight, 10- 20% Cd, 0.5-5% Sn, 0.5-5% Cu, 0.1-3% Bi and the balance Ag or further contg. 0.01-0.5% Fe group metal such as Fe, Ni or Co are internally oxidized, compressed, and sintered. The sintered body is extruded and drawn to manufacture an electrical contact material. This contact material has a low and stable contact resistance value as well as superior resistance to welding, arc and consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrical contact materials, and particularly to improvements in electrical contact materials made of Ag-Cd0.

Electrical contact materials made of Ag-Cd0 are subject to large amounts of wear due to arcing, and are inferior in arc resistance and wear resistance, resulting in deterioration of withstand voltage characteristics and insulation resistance; however, they have excellent welding resistance and stable contact resistance. Therefore, it is widely used.

In recent years, with the miniaturization of relays, there has been a trend toward a reduction in contact force and separation force, miniaturization of contacts, and narrowing of contact gaps.

For this reason, there is a demand for electrical contact materials that have excellent welding resistance, stable contact resistance, and excellent arc resistance and wear resistance.

The present invention was developed as a result of intensive research to meet such demands.
An electrical contact material has been discovered which retains the excellent welding resistance and stable contact resistance of the -Cd0 electrical contact material, and which has significantly improved arc resistance and wear resistance.

One component of the electrical contact material of the present invention is Cd 10-20% by weight, Sn 0.5-5% by weight, CuO 5-5% by weight.

It consists of BiO, 1 to 3% by weight, and the balance is Ag, and is internally oxidized.

Another electrical contact material of the present invention is Cd 10-20
Weight%, SnO, 5-5% by weight, CuO, 5-5% by weight
, BiO, 1-3% by weight, Fe group element 0.01-0.5
The balance consists of Ag and is internally oxidized.

The reason why the component composition of the electrical contact materials of the present invention is limited as described above is as follows. If it is less than 20% by weight, good welding resistance cannot be obtained, and if it exceeds 20% by weight, the abrasion resistance deteriorates even if an element that improves the abrasion resistance is added.
0% by weight is preferred. Sn has a low vapor pressure, and its oxide is very fine and thermally stable, making it resistant to abrasion.

It is necessary to improve wear resistance, and if it is less than 0.5% by weight, it will have no effect, and if it exceeds 5% by weight, Sn oxide will aggregate when the contact is opened and closed, resulting in high contact resistance and temperature rise, which will be discussed later. Since the addition of Bi cannot be suppressed completely, the amount of Bi is preferably 0.5 to 5% by weight. Cu is necessary to make the oxide finer, increase electrical conductivity, and improve wear resistance. If it is less than 0.5% by weight, it has no effect, and if it exceeds 5% by weight, the welding resistance deteriorates. 5-5 is suitable for commercially available electricity. B i is necessary to prevent the Sn oxide from agglomerating during contact opening and closing, resulting in contact resistance and temperature rise of +l'l;
If it is less than 0.1% by weight, it has no effect on bacteria, and if it exceeds 3% by weight, the melting point of the alloy will be extremely lowered, making internal oxidation at high temperatures impossible. suitable.

Fe group elements are added to further improve arc resistance and abrasion resistance, and if it is less than 0.01% by weight, it has no effect, and if it exceeds 0.5% by weight, the contact resistance is high and it may fail. Since it is stable, 0.01 to O.SV, amount % is suitable.

Next, electrical contacts made using the electrical contact material according to the present invention and the conventional electrical contact material will be explained.

Electrical contact materials of Examples 1-7 and Conventional Example 1゜2 obtained by internally oxidizing powder and granules having the composition shown in the left column of the table below, and then undergoing processes such as compression, sintering, extrusion, and drawing. Directly made with electrical contact material of ¥51ffi, l? :Size 1- fixed contact and diameter 4+am, I! V: Sa 1.1 A contact opening/closing test was conducted under the following test conditions with the 5R movable contact facing each other, and the results shown in the right column of the table below were obtained.

Test condition voltage: AC100V 50H
Z current: input 40A, constant 10A load:
Resistance opening/closing frequency: 20 times/min Opening/closing frequency: /8 until arrival/departure rate Contact force: 4og Opening gate 11 force: 45g (Left below margin) As is clear from the values shown in the right column of the table above, Examples 1 to 2
The electrical contact made of the electrical contact material No. 7 is based on the conventional example 1. 2
It can be seen that the number of times of opening and closing until welding occurs is similar to that of the electrical contact made of the electrical contact material of , and that the welding resistance is equally excellent, and the contact resistance is equally low and stable with little variation. Regarding the amount of arc consumption, Example 1~
It can be seen that the electrical contact made of the electrical contact material No. 7 has far less arc resistance and wear resistance than the electrical contact made of the electrical contact material No. 1.2.

As can be seen from the above description, the electrical contact material of the present invention has excellent welding resistance and stable contact resistance equivalent to the conventional electrical contact material made of Ag-Cd0, and also has arc resistance and
The wear resistance has been significantly improved, so it is better than the conventional A.
It can be said that it is an epoch-making product that can replace the electrical contact material made of g-Cd0.

Applicant: H” Chukikinzoku Kogyo Co., Ltd.

Claims (1)

[Claims] 1) Cd 10-20% by weight, Sn 0.5-5% by weight, CuO 15-5% by weight, Bio, 1-3% by weight
, an electrical contact material consisting of balance Ag and internally oxidized. 2) Cd 10-20% by weight, Sn 0.5-5% by weight
, CuO, 5-5% by weight, B i 0.1-
3% by weight, Fe group element 0.01-0.5% by weight, balance A
An electrical contact material consisting of g and internally oxidized.