JPS59219439A - 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, Mn 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% Mn, 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 of the electrical contact materials of the present invention contains 10 to 20% by weight of Cd, 0.5 to 5% by weight of Sn, and 0.5 to 5% by weight of Mn.

It consists of 0.1 to 3% by weight of 13i and the balance is Ag, and is internally oxidized.

Another electrical contact material of the present invention is Cd 10-20
% by weight, 5nO 15-5% by weight, Mn 0.5-5% by weight, B i O, 1-3% by weight, Fe group element 0.
01 to 0.5% by weight, the balance being 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.As is well known, Cd is necessary to maintain excellent welding resistance and stable contact resistance. 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 elements that improve the abrasion resistance are added.
0% market weight is preferred. Sn has a low vapor pressure, and its oxide is fine and thermally stable, making it arc resistant.

It is necessary to improve wear resistance, and if it is less than 0.5% by weight, there is no effect, and if it exceeds 5% by weight, Sn oxide will aggregate when the contact is opened and closed, increasing the contact resistance and temperature rise value, Since it cannot be suppressed by adding Bi, 0.5 to 5% by weight is suitable. Mn has fine oxides and is necessary to improve wear resistance and arc resistance. If it is less than 0.5% by weight, it has no effect, and if it exceeds 5% by weight, the oxide becomes layered and reduces wear resistance. .

Since the welding resistance deteriorates, the content is preferably 0.5 to 5% by weight. B i is necessary to prevent Sn oxide from agglomerating during contact opening/closing, resulting in high contact resistance and temperature rise.
．． If it is less than 1% by weight, there is no effect, and if it exceeds 3% by weight, the melting point of the alloy will be extremely lowered, making internal oxidation impossible at high temperatures, so 0.1 to 3% by weight is suitable. Fe
Group elements are arc resistant.

This is added to further improve wear resistance.
．． If it is less than 0.01% by weight, there is no effect, and if it exceeds 0.5% by weight, the contact resistance will be high and it will become unstable.
0.5 m% 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 to 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. A fixed contact with a diameter of 5 mm and a thickness of 11 m made of electrical contact material and a diameter of 4 m.
A contact opening/closing test was conducted under the following test conditions with a movable contact of 1,111 m thick and 5R facing each other.
The results shown in the right column of the table below were obtained.

Test condition voltage: AC100V 50Hz
Current 2 Input 40A, steady 10A load
: Resistance opening/closing frequency: 20 times/min Number of opening/closing: Contact force until welding occurs: 40 g Breaking force: 45 g (Hereinafter, blank space) 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 has a similar number of openings and closings until welding occurs, and has the same excellent welding resistance as the electrical contact made of the electrical contact material No. 1.2 of Conventional Example 1. It can be seen that it is equally low and stable with little variation. Regarding the amount of arc consumption, Examples 1 to 7
It can be seen that the electrical contact made of the electrical contact material of Example 1.2 has much better arc resistance and wear resistance than the electrical contact made of the electrical contact material of Conventional Example 1.2.

As can be seen from the above description, the electrical contact material of the present invention has excellent melting resistance and stable contact resistance equivalent to the conventional electrical contact material made of Ag-Cd0, and also has arc resistance and Since the wear resistance has been significantly improved, it can be said to be an epoch-making product that can replace the conventional electrical contact material made of Ag-Cd0.

Applicant: Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (1)

[Claims] 1) Cd 10-20% by weight, Sn (1.5-5% by weight, Mn 0.5-5% by weight, BiO, 1-3% by weight,
An electrical contact material whose remainder is made of Ag and which is internally oxidized. 2) CdlO~20% by weight, Sn 0.5~5
Weight %, Mn 0.5-5 weight %, B i 0.
An electrical contact material consisting of 1 to 3% by weight, 0.01 to 0.5% by weight of Fe group elements, and the balance being Ag, and which is internally oxidized.