JPS60245746A - Electrical contact material - Google Patents

Abstract

PURPOSE:To obtain an electrical contact material having stable contact resistance and superior welding resistance by compressing and sintering internally oxidized alloy powder having a specified composition consisting of Ag, Bi, Cd and Cu or further contg. an Fe group metal and by extruding and drawing the sintered body. CONSTITUTION:A molten alloy consisting of, by weight, 5-20% Bi, 0.1-5% Cd, 0.5-5% Cu and the balance Ag or further contg. 0.01-1% Fe group metal such as Ni is atomized, and the resulting powder is internally oxidized. The powder is then compressed and sintered, and the sintered body is extruded, drawn, and cut to obtain an electrical contact material. This electrical contact material has stable contact resistance and superior welding resistance.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to electrical contact materials.

(Prior Art and its Problems) Silver-bismuth oxide has conventionally been used as one of the electrical contact materials manufactured by internal oxidation method. Silver-bismuth oxide has contact performance such as excellent arc resistance and welding resistance, and stable contact resistance. As gear knobs become narrower, welding resistance has become a problem. For this reason, there is a demand for electrical contacts with even better welding resistance.

The present invention was developed as a result of intensive research to meet such demands.
An electrical contact material has been discovered that retains the stable contact resistance of an electrical contact material made of bismuth oxide and has greatly improved welding resistance.

(Means for Solving the Problems) One of the electrical contact materials of the present invention contains 5 to 20% by weight of bismuth, 0.1 to 5% by weight of cadmium, 0.5 to 5% by weight of copper, and the balance. It is a material made of silver and is internally oxidized.

Other brim of the electrical contact material of the present invention: Hismuth 5 to 2
0% by weight, cadmium 0.1-5% by weight, copper 0.5-5% by weight
5% by weight, 0.01 to 1% by weight of iron group elements, and the balance is silver, and is internally oxidized.

(Function) In the electrical contact material of the present invention, bismuth 5-2 Oi amount %, cadmium 0.1-5 weight %, copper 0.5-5 weight %
The reason for this is that the market amount of bismuth is less than 5%.

If cadmium is less than 0.1% by weight, good welding resistance cannot be obtained, and if bismuth exceeds 20% by weight, the melting point of the alloy will be too low, making internal oxidation at high temperatures difficult. Cadmium is useful for improving welding resistance, but when it exceeds 5% by weight, it deteriorates the welding resistance of silver-bismuth oxide. On the other hand, in the case of copper, it has the effect of making the oxide particles uniform, so there is less variation in welding resistance.If it is less than 0.5% by weight, it has no effect, and if it exceeds 5% by weight, it deteriorates the welding resistance. From the above, bismuth 5-20% by weight, force Fmium 0.1
Within the range of 5% by weight of copper and 0.5% to 5% by weight of copper, an electrical contact material with sufficiently satisfactory welding resistance can be obtained.

Furthermore, in another electrical contact material of the present invention, in addition to 5 to 20% by weight of hismuth, 0.4 to 5% by weight of cadmium, and 0.5 to 5% by weight of copper, 0.01 to 1% of iron group elements The reason for adding % by weight is that when dispersed in electrical contact materials,
This is because the uniform and fine dispersion of bismuth oxide and oxidizing power F-mium that is obtained in this way equalizes consumption due to discharge, making the contact resistance more stable.
If the weight percent is less than 1+Yi, bismuth oxide and cadmium oxide will not be uniformly and finely dispersed, and if it exceeds 1 weight percent, segregation of themselves will increase and the contact resistance will become unstable.

Next, in order to clarify the effects of the electrical contact material according to the present invention, specific examples and conventional examples will be described.

(Example) Materials not shown in the left column of the table below having the compositions of Examples 1 and 2 were melted to form atomized powder, and then heated at 600°C, 9 atm,
After internal oxidation for 2 days, this oxidized atomized powder was compressed and sintered, extruded and drawn, and then cut and processed into headers. ．． Fixed contact with leg length 2.5mm and head (% (Flea 4 dragons 5 heads height 1.1m)
m, leg diameter 2.8 feet 1 leg length 1.61 + 1° head height spherical 5R
The movable contact was i#.

In addition, a material having the composition of Example 3.4 shown in the left column of the table below is melted, formed into a chip shape, internally oxidized at 600°C and 9 atm for 2 days, then compressed and sintered, and then extruded. , After drawing, cutting and header processing, head diameter 5, il
Height 1.0IITI, leg diameter 2. '5mm.

Leg length 2.5 dragon fixed contact, head diameter 4 fins, height 1.1 fins.

A movable contact with a leg diameter of 2.8, a fin leg length of 1.6+m, and a spherical head of 5R was obtained.

However, Lichenoto type electrical contacts made with the electrical contact materials of Examples 1 to 4 and the same dimensions made using the materials of the conventional examples shown in the left column of the table below in the same manner as in Example 1.2. When the Lichenoto type electrical contact was assembled into a hinge type relay and an opening/closing test was conducted under the following test conditions, the results shown in the right column of the table below were obtained.

Test conditions Voltage: AC100V 50Hz Current 2 input 40A, steady 10A load:
Resistance switching frequency: 20 times/min Number of switching operations: Until welding occurs (effects of the invention) As is clear from the table above, the head-type electrical contacts made with the electrical contact materials of Examples 1 to 4 are different from the conventional electrical contacts. It can be seen that compared to electrical contacts made of other materials or head-type electrical contacts, the number of openings and closings before welding occurs is greater, the welding resistance is low, and the contact resistance is equally low and stable with little variation. More than f9
As mentioned above, the electrical contact material of the present invention has a stable contact resistance equivalent to that of the conventional electrical contact material made of silver-bismuth, and has significantly improved welding resistance, which is superior to the conventional electrical contact material. It can be said to be an epoch-making product that can be replaced.

Applicant Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (1)

[Claims] ■) 5 to 20% by weight of bismuth and 0.1 to 5% of cadmium
An electrical contact material comprising 0.5-5% by weight of copper and the balance silver, and which is internally oxidized. 2) 5-20% by weight of bismuth and 0.1-5% of cadmium
% by weight, 0.5-5% by weight of copper, and 0.01-1% by weight of iron group elements.
% by weight, the balance being silver, and which is internally oxidized.