JPS60248850A - 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 Mn to Ag and carrying out internal oxidation. CONSTITUTION:A material consisting of, by weight, 5-20% Bi, 5-10% Cd, 0.5- 8% Sn, 0.5-8% Mn 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 which retains the stable contact resistance of an electrical contact material made of bismuth oxide and which 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, more than 5% by weight and 10% by weight of cadmium, and 0% by weight of tin.
．． It is a material consisting of 5 to 8% by weight of manganese, 0.5 to 8% by weight of manganese, and the balance silver, and is internally oxidized.

Another electrical contact material of the present invention is bismuth 5-20
% by weight, and more than 5% by weight and less than 10% by weight of cadmium,
It is a material consisting of 0.5 to 8% by weight of tin, 0.5 to 8% by weight of manganese, and the balance silver, and is internally oxidized.

In the electrical contact material of the present invention, bismuth is 5 to 20% by weight, cadmium is more than 5% by weight and 10% by weight or less, and tin is 0%.
．． The reason why bismuth and cadmium are set at 5 to 8% by weight and 0.5 to 8% by weight is that bismuth and cadmium improve welding resistance by their low-temperature sublimation properties, and if bismuth is less than 5% by weight and cadmium is less than 5% by weight, this effect is reduced. If cadmium exceeds 20% by weight, the melting point of the alloy will be too low and internal oxidation at high temperatures becomes difficult, and if cadmium exceeds 10% by weight, the welding resistance of silver-bismuth oxide will deteriorate. The purpose of tin is to change the spherical precipitation of cadmium into a needle shape and improve the welding resistance.If it is less than 0.5% by weight, it has no effect, and if it exceeds 8% by weight, the welding resistance improves, but when the contacts are opened and closed, oxides are formed. condenses on the contact surface, increasing contact resistance and temperature rise. Manganese is used to improve welding resistance; if it is less than 0.5% by weight, it will not have that effect, and if it exceeds 8% by weight, layered precipitation will occur and contact resistance will decrease.

The temperature rise becomes large. From the above, bismuth 5-20
Within the range of cadmium exceeding 5% by weight and 10% by weight or less, tin 0.5 to 8% by weight, and manganese 0.5 to 8% by weight, an electrical contact material with sufficiently satisfactory welding resistance properties can be obtained. It is.

Furthermore, in another one of the electrical contact materials of the present invention, bismuth is 5 to 20% by weight, cadmium is more than 5% by weight and 10% by weight or less, tin is 0.5 to 8% by weight, and manganese is 0.5 to 8% by weight. The reason for adding 0.01 to 1% by weight of iron group elements in addition to 0.01% to 1% by weight is that when this is dispersed in electrical contact materials, the resulting uniform and fine dispersion of hismuth oxide and cadmium oxide ensures uniform consumption due to discharge. If it is less than 0.01% by weight, hismuth 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 more stable. becomes unstable.

(Examples and Conventional Examples) Materials having the component compositions of Examples 1 and 2 shown in the left column of the table below were melted, mixed with atomized powder, and then internally oxidized at 600°C and 29 atmospheres for 2 days. 1-Mize powder is compressed and sintered, extruded and drawn, then cut and processed to give a head diameter of 5 mm, head height of 1.0, and leg diameter of 2. Plow 1
Fixed contact with leg length 2.5 fl and head diameter 4 cranes 2 heads height 1.1 m
'+ leg diameter 2,811 m, leg length 1. - A movable contact with a two-head high spherical shape of 5R was obtained.

In addition, after melting the materials having the compositions of Examples 3 and 4 shown in the left column of the table below and forming them into a chi-nob shape,
After internal oxidation at atmospheric pressure for 2 days, compression sintering is performed, and this is extruded.
After drawing and cutting, the head diameter was 5.
m+*, head height 1. Q+u+, leg diameter 2.5 inches.

Fixed contact with leg length 2.51 mm, head diameter 4 mm, and head height 1.1 weight.

Leg diameter 2.8mm, leg length 1. A movable contact with a spherical head 5R was obtained.

However, these electrical contacts made from the electrical contact materials of Examples 1 to 4 and the same type electrical contacts made using the same method as Examples 1 and 2 using the material of the conventional example shown on the left side of the table below. When a rib-throat type electrical contact with the same dimensions was assembled into a hinge type relay and an opening/closing test was conducted under the test conditions below, the results shown in 1 in the right column of the table below were obtained.

Test conditions Voltage: AC100V 50H, Current: 40A input, steady 10A load: Resistance Switching frequency: 20 times/min Number of switchings: Until welding occurs (blank below) As is clear from the table above, Example 1 Compared to rivet-type electrical contacts made with conventional electrical contact materials, head-type electrical contacts made with ~4 electrical contact materials have a higher number of openings and closings before welding occurs, have excellent welding resistance, and have the same contact resistance. It can be seen that it is low and stable with little variation.

(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] 1) 5 to 20% by weight of bismuth, more than 5% by weight of cadmium and 10% by weight or less, 0.5 to 8% by weight of tin, 0.5% by weight of manganese.
An electrical contact material comprising 5 to 8% by weight, the balance being silver, and which is internally oxidized. 2) Bismuth 5-20% by weight, cadmium more than 5% by weight and less than 10% by weight, tin 0.5-8% by weight, manganese 0.
An electrical contact material comprising 5 to 8% by weight of an iron group element, 0.01 to 1% by weight of an iron group element, and the balance silver, and which is internally oxidized.