JPS59185747A - 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 Mn, Bi and an Fe group element, and carrying out internal oxidation. CONSTITUTION:An electrical contact material is obtd. by internally oxidizing an alloyconsisting of, by weight, 10-20% Cd, 0.5-5% Mn, 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-CaO.

Electrical contact materials made of Ag-Cd0 are highly abrasive due to arcing, and have poor arc resistance and abrasion resistance, resulting in deterioration of withstand voltage characteristics and insulation resistance, but they have excellent welding resistance and stable contact resistance. Therefore, it is widely used.

Recently, with the miniaturization of relays, there has been a trend toward a decrease in contact force, opening & 11 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 -CaO electrical contact materials, and has significantly improved arc resistance and wear resistance.

One of the electrical contact materials of the present invention is Cd1O~20% by weight
, Mn, 0.5-5% by weight, BiO, 1-3% by weight.

The remainder consists of Ag and is internally oxidized.

Another electrical contact material of the present invention is Cd 10-20
Weight %, Mn 0.5-5 weight %, B i 0
．． 1 to 3% by weight, Fe group element 0.01 to 0.5% by weight,
The remainder 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: Cd is necessary to maintain excellent welding resistance and stable contact resistance, and is 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% by weight is preferred. Mn has a low vapor pressure, and its oxide is fine and thermally stable, making it arc resistant.

Necessary for improving wear resistance; if it is less than 0.5% by weight, there is no effect; if it exceeds 5% by weight, Mn oxide will precipitate in a layer during internal oxidation, resulting in contact resistance and temperature rise when opening and closing the contact. Since the value becomes high and cannot be suppressed by adding Bi, which will be described later, 0.5 to 5% by weight is suitable. Bi is necessary to prevent Mn oxides from precipitating in layers during internal oxidation, increasing the contact resistance and temperature rise when opening and closing the contacts, and is 0.
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 at high temperatures 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 unstable. Therefore, 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 mm and a diameter of 411 mm was made from the electrical contact materials of No. 7 to 7 and the electrical contact materials of Conventional Examples 1 to 2. 1.1mm thick, facing the 5R movable contact,
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 condition voltage: AClooV 50Hz voltage
Current: Input 40A, constant 10A load:
Resistance opening/closing frequency: 20 times/min Number of opening/closing: Contact force until welding occurs: 40 g Breaking force = 45 g 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 contacts made of the electrical contact materials No. 1 and 2 of Conventional Examples 1 and 2. It can be seen that the value is low and stable with little variation. Regarding the amount of arc consumption, Examples 1 to 7
It can be seen that the electrical contacts made of the electrical contact materials shown in FIG.

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-CdQ, 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 -C'd O.

Applicant: Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (1)

[Claims] 1) Cd 10-20'FJZ amount %, Mn 0.
An electrical contact material consisting of 5 to 5% by weight, B2O, 1 to 3% by weight, and the balance Ag, and which is internally oxidized. 2) CdlO~20% by weight, MnO, 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.