JPS60245741A - 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, Sn and Zn or further contg. an Fe group metal and by extruding the sintered body. CONSTITUTION:A molten alloy consisting of, by weight, 13-20% Bi, 0.1-5% Cd, 0.5-5% Sn, 0.5-5% Zn 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, but recently, as relays have become smaller, contact cuff opening force has decreased, contacts have become smaller, and contact gear knobs have become smaller. With the narrowing of the area, problems have arisen in welding resistance. For this reason, there is a demand for electrical contact materials with even better welding resistance.

The present invention was developed as a result of intensive research to meet such demands.
We have discovered an electrical contact material that retains the stable contact resistance of the electrical contact material made of bismuth oxide and has significantly improved welding resistance. One is 13-20% by weight of bismuth, 0.1-5% by weight of cadmium, and 0.5-5% by weight of cadmium.
The material consists of 0.5-5% by weight of zinc and the balance silver, and is internally oxidized.

Another electrical contact material of the present invention is bismuth 13-2
0% by weight, 0.1-5% by weight of cadmium, and 0.5% by weight of tin.
~5% by weight, 0.5-5% zinc, and 0.0% iron group elements
It is a material consisting of 1 to 1% by weight, the balance being silver, and is internally oxidized.

(Function) The reason why the electrical contact material of the present invention is made 13 to 20% by weight of bismuth, 0.1 to 5% by weight of cadmium, 0.5 to 5% by weight of tin, and 0.5 to 5% by weight of zinc is , bismuth, and cadmium are used to improve welding resistance through low-temperature sublimation, and bismuth is less than 13% by weight and cadmium is 0.1% by weight.
If it is less than 20% by weight of bismuth, there is no effect; if it exceeds 20% by weight of bismuth, the melting point of the alloy decreases and internal oxidation at high temperatures becomes difficult, and if it exceeds 5% by weight of cadmium, the welding resistance of silver-bismuth oxide decreases. deteriorate. The purpose of tin is to change the spherical precipitation of Mium into a needle shape and improve welding resistance. If it is less than 0.5% by weight, it has no effect, and if it exceeds 5% by weight, oxides will form on the contact surface when the contact is opened or closed. Zinc deposits and increases contact resistance and temperature rise.Zinc improves welding resistance due to its thermal stability as an oxide, and if it is less than 0.5% by weight, it has no effect; If it exceeds 13% to 20% by weight of bismuth and 0.1% of cadmium, contact resistance and temperature increase will increase due to layered precipitation.
Within the range of ~5% by weight, 0.5% to 5% by weight of tin, and 0.5% to 5% by weight of zinc, an electrical contact material with sufficiently satisfactory welding resistance can be obtained.

Furthermore, in another electrical contact material of the present invention, 13 to 20% by weight of bismuth, 0.1 to 5% by weight of cadmium,
The reason for adding 0.01 to 1% by weight of iron group elements in addition to 0.5 to 5% by weight of tin and 0.5 to 5% by weight of zinc is that when dispersed in electrical contact materials, the resulting oxidation This is because bismuth oxide and cadmium oxide are uniformly and finely dispersed, and consumption due to discharge becomes uniform, so contact resistance becomes more stable. If it exceeds 1% by weight, segregation of itself increases and contact resistance becomes 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) After melting the materials having the compositions of Examples 1 and 2 shown in the left column of the table below to form atomized powder, the mixture was 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 hesogroometry.The head diameter was 5 pieces, the height of each head was 1.01, the leg diameter was 2.5+nm, Fixed contact of tuna with leg length 2.5 and head 1 thread 419 head height 1.1 mm
, leg length 2.8, fin length 1.6 dragon.

A movable contact with a spherical head height of 5R was obtained.

In addition, a material having the composition of Example 3.4 shown in the left column of the table below was melted, formed into a chip shape, internally oxidized at 600"C + 9 atm for 2 days, then compressed and sintered, and then extruded. After drawing it, it was cut and processed with heso-groove processing, and the head diameter was 5, the height of each dragon was 1.Q mm, and the leg diameter was 2.5 m.

Leg length 2.5 fin fixed contact, head diameter 4+im, head height 1.1
1゜Leg diameter 2.3mm, leg length 1.6mm, head spherical 5R
A movable contact was obtained.

However, head-type electrical contacts were made using the electrical contact materials of Examples 1 to 4, and contact materials were made using the same method as in Example 1.2 using the materials having the compositions of the conventional examples shown in the left column of the table below. −
When a glue-bet 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: AC 100V 50Hz Current 2 Input 40A, Steady 10A load: Resistance Switching frequency: 20 times/min Switching/closing frequency: Until welding occurs (hereinafter referred to as blank space) (Effects of the invention) As is clear from the table above The recess type electrical contacts made with the electrical contact materials of Examples 1 to 4 can open and close more times before welding occurs, and have excellent welding resistance and lower contact resistance than conventional electrical contact materials or head-type electrical contacts. It can be seen that the values are equally low and stable with little variation. As detailed 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,
Furthermore, the adhesive resistance has been significantly improved, and it can be said to be an epoch-making product that can replace conventional electrical contact materials.

Applicant Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (1)

[Claims] 1) 13 to 20% by weight of bismuth and 0.1 to 0.1 to cadmium
5% by weight, tin 0.5-5% by weight, zinc 0.5-5% by weight
and an internally oxidized electrical contact material, the balance being silver. 2) 13-20% by weight of bismuth and 0.1-0.1% of cadmium
5% by weight, tin 0.5-5% by weight, zinc 0.5-5% by weight
, 0.01 to 1% by weight of an iron group element, and the balance being silver, and is internally oxidized.