JPS59185751A - Electrical contact material - Google Patents

Abstract

PURPOSE:To obtain an electrical contact material having improved arc resistance and consumption resistance by blending an Ag-Cd alloy with specified amounts of Sn, Bi and an Fe group element, and carrying out internal oxidation. CONSTITUTION:An electrical contact material is obtd. by internally oxidizing an alloy consisting of, by weight, 15-20% Cd, 0.5-5% Sn, 0.1-3% Bi and the balance Ag or further contg. 0.01-0.5% Fe group element. This electrical contact material has superior welding resistance and stable contact resistance which are equal to those of a conventional Ag-CdO material, and it has considerably improved arc resistance and consumption resistance.

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, as relays have become smaller, there has been a trend toward lower contact and separation forces, smaller contacts, and smaller contact gears. Therefore, it has excellent welding resistance and stable contact resistance.
There is also a demand for electrical contact materials that have excellent arc resistance and wear resistance.

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

One of the electrical contact materials of the present invention has Cd 15-20% by weight, Sn 0.5-5% by weight, B i 0.1
It consists of ~3% by weight, the balance being Ag, and is internally oxidized.

Another electrical contact material of the present invention is Cd 15-20
It consists of 0.5 to 5 weight % Sn, 1 to 3 weight % Bio, 0.01 to 0.5 weight % Fe group elements, and the balance 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, and Cd is necessary for maintaining 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 abrasion resistance are added.
0% by weight is preferred. Sn has a low vapor pressure, and its oxide is very 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 13i, 0.5 to 5
% by weight is preferred. Bi is necessary to prevent Sn oxides from agglomerating during contact opening and closing, increasing the contact resistance and temperature rise, and if it is less than 0.1% by weight, it has no effect;
If it exceeds 0.1 to 3% by weight, the melting point of the alloy will be extremely lowered and internal oxidation at high temperatures will become impossible, so 0.1 to 3% by weight is preferable. Fe group elements are added to further improve arc resistance and abrasion resistance; 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 is not effective. Since it becomes stable, 0.01 to 0.5% by weight 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.

Example 1 internally oxidized with the component composition shown in the left column of the table below
A fixed contact with a diameter of 5 mm and a thickness of 1 square made of the electric contact material of Y7 and the electric contact materials of Conventional Examples 1 and 2 was made to face a movable contact of 4 mm in diameter, 1.1++n in thickness, and 5R. A contact opening/closing test was conducted under the following test conditions, and the results shown in the right column of the table below were obtained.

Test conditions Voltage: AClooV 50Hz current 2 Input 40A, steady 10A load:
Resistance opening/closing frequency: 20 times/min Opening/closing frequency: Contact force until welding occurs = 40g Separation force = 45g 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 as the electrical contacts made of the electrical contact materials of Conventional Examples 1 and 2, has excellent welding resistance, and has a lower contact resistance. It can be seen that it is equally low and stable with little variation. Regarding the amount of arc consumption, Example 1~
It can be seen that the electrical contacts made of the electrical contact material No. 7 have far less arc resistance and excellent wear resistance than the electrical contacts made of the electrical contact materials of Conventional Examples 1 and 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-CaO.

Applicant: Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (1)

[Scope of Claims] 1) An electrical contact material consisting of 15 to 20% by weight of Cd, 0.5 to 5% by weight of Sn, 1 to 3% by weight of B, and the balance being Ag, and which is internally oxidized. 2:l Cd 15-20% by weight, Sn 0.
5-5% by weight, Bio, 1-3% by weight, Fe group element 0.
01-0.5% by weight. An electrical contact material whose remainder is made of Ag and which is internally oxidized.