JPH0235018B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to electrical contact materials, particularly Ag-
Concerning improvements in electrical contact materials made of CdO. Electrical contact materials made of Ag-CdO have excellent welding resistance when the contact force and breaking force of relays are large.
It is widely used because of its stable contact resistance. Recently, as relays have become smaller, contact force and separation force have decreased, contacts have become smaller, and contact gaps have become narrower, resulting in problems with welding resistance. For this reason, there is a demand for electrical contact materials with excellent welding resistance. The present invention has been made as a result of intensive research aimed at meeting such needs, and has resulted in the discovery of an electrical contact material that retains the stable contact resistance of electrical contact materials made of Ag/CdO and has significantly improved welding resistance. . One of the electrical contact materials of the present invention is Cd 10-20% by weight, Sb 0.5-5% by weight, Cu 0.5-5% by weight,
It consists of 0.1 to 3% by weight of Bi and the balance is Ag, and is internally oxidized. Another electrical contact material of the present invention is Cd10~
20% by weight, Sb0.5-5% by weight, Cu0.5-5% by weight,
It consists of 0.1 to 3% by weight of Bi, 0.01 to 0.5% by weight of Fe group elements, and the balance is 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 an element that improves abrasion resistance is added, so 10 to 20% by weight is preferable. . Sb is necessary for improving welding resistance because its oxide tends to evaporate when opening and closing contacts; less than 0.5% by weight has no effect, and more than 5% by weight deteriorates wear resistance. Since the amount cannot be suppressed, 0.5 to 5% by weight is suitable. Cu is necessary to refine the oxides precipitated during internal oxidation, increase electrical conductivity, and improve wear resistance. If it is less than 0.5% by weight, the deterioration of wear resistance due to the addition of Sb and Bi cannot be suppressed. If it exceeds 5% by weight, the welding resistance deteriorates, so 0.5 to 5% by weight is suitable. Bi is necessary to improve the welding resistance when the contact force and opening force are small because its oxide tends to sublimate when opening and closing the contacts.If it is less than 0.1% by weight, it has no effect, and if it exceeds 3% by weight, the alloy will Since it extremely lowers the melting point and makes internal oxidation impossible at high temperatures, it is preferably 0.1 to 3% by weight. Fe group elements are added to improve arc resistance and wear 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 becomes unstable, so 0.01 to 0.5
% by weight is preferred. 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 Examples 1 and 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 contact opening/closing test was conducted under the following test conditions by placing a fixed contact with a diameter of 5 mm and a thickness of 1 mm made of electrical contact material of The results shown in the right column of the table below were obtained. Test conditions Voltage: AC100V 50Hz Current: 40A, steady 10A Load: Resistance Switching frequency: 20 times/min Number of switching: Contact force until welding occurs: 40g Breaking force: 45g

[Table] As is clear from the values shown in the right column of the table above, the electrical contacts made of the electrical contact materials of Examples 1 to 7 are as follows:
Compared to the electrical contacts made of the electrical contact materials of Conventional Examples 1 and 2, it can be seen that the number of openings and closings before welding occurs is greater, and the welding resistance is excellent, and the contact resistance is equally low and stable with less variation. . As for the amount of arc consumption, it can be seen that the electrical contacts made of the electrical contact materials of Examples 1 to 7 are equal to or less than the electrical contacts made of the electrical contact materials of Conventional Examples 1 and 2. As can be seen from the above explanation, the electrical contact material of the present invention has a stable contact resistance equivalent to that of the conventional electrical contact material made of Ag-CdO, and has significantly improved welding resistance. , conventional Ag−
It can be said to be an epoch-making product that can replace electrical contact materials made of CdO.

Claims (1)

[Claims] 1 Cd 10-20% by weight, Sb 0.5-5% by weight, Cu 0.5
An electrical contact material consisting of ~5% by weight, 0.1~3% by weight of Bi, and the balance being Ag, and is internally oxidized. 2 Cd10-20% by weight, Sb0.5-5% by weight, Cu0.5
~5% by weight, Bi0.1~3% by weight, Fe group element 0.01~
Electrical contact material consisting of 0.5% by weight, balance Ag, and internally oxidized.