JPS59215439A - Electrical contact material - Google Patents

Abstract

PURPOSE:To obtain an electrical contact material having stable contact resistance and much superior welding resistance by internallly oxidizing an alloy material having a specified composition consisting of Cd, In, Sb, Bi and the balance Ag. CONSTITUTION:This electrical contact material is obtd. by internally oxidizing an alloy material having a composition consisting of, by weight, 10-20% Cd, 0.5-5% In, 0.5-5% Sb, 0.1-3% Bi and the balance Ag. The composition may further contain 0.01-0.5% Fe group element.

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-CaO are widely used because they have excellent adhesion resistance and stable contact resistance when the contact force and separation force of relays are large.

Recently, as relays have become smaller, contact force and separation force have decreased, contacts have become smaller, and contact gears 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 was developed as a result of intensive research to meet such demands.
An electrical contact material has been discovered which has the same stable contact resistance as the electrical contact opening material made of -Cd0 and has significantly improved welding resistance.

One of the electrical contact materials of the present invention, Cd 10-2001
i%, In 0.5-5111m%, S b
O, 5-5i1i amount%.

It is composed of Bjo, 1 to 3%, and the balance is Ag, and is internally oxidized.

Another electrical contact material of the present invention is Cd lQ~20
Weight %, I n 0.5-5 weight [%, S b
O, 5-51ift)%, B i O, 1-3
Weight %, E group element 0.01-0.5M maximum %, lj<f
It is made of aAg 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 10%, good welding resistance will not be obtained, and if it exceeds 20% by weight, wear resistance will deteriorate even if elements that improve wear resistance are added.
20 ton % is suitable. In is necessary to improve welding resistance, and if it is less than 0.5% by weight, there will be no effect, and if it is less than 5% by weight,
If it exceeds 0.5% to 5% by weight, the In oxide will aggregate during contact opening/closing, resulting in higher contact resistance and temperature rise, which cannot be suppressed by adding 13i, which will be described later. sb is necessary for welding resistance because its oxide has a high vapor pressure, and if it is less than 0.5% by weight, it has no effect, and if it exceeds 5% by weight, wear resistance deteriorates.
0.5-5% by weight is preferred. B i has a weak contact force because its oxide is brittle and dissociates easily.

It is necessary to improve welding resistance when the opening force is small, and to prevent In oxides from agglomerating during contact opening and closing, resulting in high contact resistance and temperature rise. If the amount exceeds 3% by weight, the melting point of the alloy will be extremely lowered and internal oxidation with high 61!I will become impossible, so 0.1 to 3% by weight is preferable. The element is added to improve arc resistance and wear resistance 171, so if it is less than 11% by weight, it has no effect, and if it exceeds 0.5% by weight, contact 11 (resistance is high and unstable). Therefore, 0
．． 01 to 0.5% by weight is preferred.

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

After internally oxidizing the powder having the composition shown in the left column of the table below, the electrical contact materials of Examples 1 to 7 and Conventional Example 1 were processed through processes such as compression, sintering, extrusion, and drawing. A fixed contact with a diameter of 5+1.mm, ff4 mm, made from electrical contact side material of ゜2 mm, and a movable contact with a diameter of 4 mm, a thickness of 1 mm, and 51 mm were placed facing each other (under the following test conditions). When we conducted a contact opening/closing test, we obtained the results shown on the right side of the table below (1"il).

Test conditions Voltage: AClooV 50Hz current 2 input 4OA, steady 1oΔ negative force:
Resistance switching frequency: 20 times/min Number of switching operations: Until 166 occurrences Contact force: 40 g Breaking force: 45 g From the electrical contact materials of Examples 1 to 7 as shown on the right side of the table (1y1) Compared to the electrical contacts made of the electrical contact materials O and 4 of Conventional Examples 1 and 2, the electrical contacts made of the above-mentioned electrical contacts have a greater number of openings and closings before welding occurs, and have excellent welding resistance.
) It can be seen that the 1B resistance is equally low and stable with little variation. It can be seen that the arc consumption of the electrical contacts made of the electrical contact materials of Examples 1 to 7 is equal to or less than that of the electrical contacts made of the electrical contact 4/I material of Conventional Example 1.2.

As can be seen from the above description, the electrical contact material of the present invention is suitable for the conventional electrical contact 1. made of Δg-CdO. It has a stable contact resistance equivalent to that of + and has significantly improved welding resistance, making it an epoch-making product that can replace the conventional electrical contact material made of △tz-CdO. I can say that.

Claims (1)

[Claims] 1) Cd 10-20% by weight, In 0.5-5
ii%, 3bO15-5% by weight, Bi0.1-3% by weight
, an electrical contact material consisting of balance Ag and internally oxidized. 2) Cd LO~20'fmMkg6,I
n 0.5~5' fj electrical contact material.