JPS60248842A - Electrical contact material - Google Patents

Abstract

PURPOSE:To obtain an electrical contact material having stable contact resistance and considerably improved welding resistance by adding specified percentages of Bi, Cd, Sn and Sb to Ag and carrying out internal oxidation. CONSTITUTION:A material consisting of, by weight, 13-20% Bi, 0.1-5% Cd, 0.5-5% Sn, 0.5-5% Sb and the balance Ag or further contg. 0.01-1% Fe group element is internally oxidized to obtain the electrical contact material. Stable electrical contacts which hardly vary are obtd. by using the electrical contact material.

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 the gap narrows, problems have arisen in welding resistance. For this reason, there is a demand for electrical contact materials with even better welding resistance.

(Object of the Invention) The present invention has been made to meet such a demand, and is
It is an object of the present invention to provide an electrical contact material that maintains 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 13-20% by weight of bismuth, 0.1-5% by weight of cadmium, 0.5-5% by weight of tin, and 0.5% by weight of antimony. It is a material consisting of 5 to 5% by weight, the balance being silver, and is internally oxidized.

Another electrical contact material of the present invention is bismuth 13-2
0% by weight, cadmium 0.1~5% by weight, tin 0.5~
5% by weight of antimony, 0.5-5% by weight of antimony, and the balance of silver, and is internally oxidized.

In the electrical contact material of the present invention, 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 antimony are included. This is because cadmium improves welding resistance through its low-temperature sublimation properties; less than 1.3% by weight of bismuth and less than 0.1% by weight of cadmium has no effect; and more than 20% by weight of bismuth lowers the melting point of the alloy too much. Therefore, internal oxidation at high temperatures becomes difficult, and if cadmium exceeds 5% by weight, the welding resistance of silver-bismuth oxide deteriorates. The purpose of tin is to change the spherical precipitation of cadmium 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, the welding resistance improves, but when the contacts are opened and closed, oxides are formed. is deposited on the contact surface, increasing contact resistance and temperature rise. Antimony is also used to improve welding resistance; if it is less than 0.5% by weight, it will not have that effect, and if it exceeds 5% by weight, the processability will be extremely deteriorated. From the above, bismuth 13-20% by weight, cadmium 0.1-5% by weight, tin 0.5-5% by weight
, within the range of 0.5 to 5% by weight of antimony, 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 uniform and fine dispersion of bismuth oxide and cadmium oxide obtained by mixing 0.5 to 5% by weight of tin and 0.5 to 5% by weight of antimony makes the contact resistance more stable because consumption due to discharge becomes uniform. If the amount is less than 0.01% by weight, bismuth oxide and cadmium oxide will not be uniformly and finely dispersed, and if it exceeds 1% by weight, their segregation will increase and the contact resistance will become unstable.

(Example and Conventional Example) The material having the component composition of Example 1.2 shown in the left column of the table below was melted to form an atomized powder, and then internally oxidized at 600°C and 19 atmospheres for 2 days. 1 size powder is compressed and sintered, extruded and drawn, then cut and processed into headers, with a head diameter of 5 mm, an i height of 1.0 w1t, and a leg diameter of 2.5 m.
, Fixed contact with leg length 2.5fi, head diameter 4 fins, height 1.1+n, leg diameter 2.8m, leg length 1.5in.

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

In addition, materials having the compositions of Examples 3 and 4 shown in the left column of the table below are melted and formed into chip shapes, which are internally oxidized at 600°C and 9 atm for 2 days, then compressed and sintered, and then extruded. , After drawing, cutting and header processing L, head diameter 5 dragon 1 head height 1. O1+m, leg diameter 2.5+*m.

Fixed contact with leg length 2.5 fl, head diameter 4 fl, and head height 1. i
nn.

Leg diameter 2.811m, leg length 1. [3 Leopard, a movable contact with a spherical head 5R was obtained.

However, the rehesoto type electrical contacts made using the electrical contact materials of Examples 1 to 4 and the same size electrical contacts made by the same method as Example 1.2 using the materials of the conventional examples shown in the left column of the table below. When a glue bent 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 inputs 40A, steady 10A load; Resistance switching frequency: 20 times/min Number of switchings: Until welding occurs (blank below) As is clear from the table above, Examples 1 to 4 Bent-type electrical contacts made with electrical contact materials require more opening and closing times before welding occurs than conventional electrical contact materials made with bent-type electrical contacts (they have excellent welding resistance, have an equally low contact resistance, and It can be seen that there is little variation and it is stable.

(Effects of the Invention) 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, and has significantly improved welding resistance. Therefore, 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] ■) Bismuth 13-20% by weight, cadmium 0.1-5
An electrical contact material comprising 0.5-5% by weight of tin, 0.5-5% by weight of antimony, and the balance silver, and which is internally oxidized. 2) Bismuth 13-20% by weight, cadmium 0.1-5
A material consisting of 0.5-5% by weight of tin, 0.5-5% by weight of antimony, 0.01-1% by weight of iron group elements, and the balance silver, and which is internally oxidized. Contact material.