JPS60248838A - 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, In and Te to Ag and carrying out internal oxidation. CONSTITUTION:A material consisting of, by weight, 1-20% Bi, 0.1-5% Cd, 0.5-5% In, 0.5-5% Te 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 developed to meet such demands, and provides an electrical contact material that has the stable contact resistance of the electrical contact material made of silver-bismuth oxide and has significantly improved welding resistance. We aim to provide the following.

(Means for Solving the Problems) One of the electrical contact materials of the present invention is bismast 20% by weight.
, cadmium 0.1-5% by weight, indium 0.5-5% by weight
5% by weight of tellurium, 0.5-5% by weight of tellurium, and the balance of silver, and is internally oxidized.

Another electrical contact material of the present invention includes 20% by weight of bismast, 0.1 to 5% by weight of cadmium, and 0.1 to 5% by weight of indium.
The material is composed of 5 to 5% by weight of tellurium, 0.5 to 5% by weight of tellurium, and the balance silver, and is internally oxidized.

In the electrical contact material of the present invention, 20% by weight of bismast
, cadmium 0.1-5% by weight, indium 0.5-5% by weight
The reason for using 5% by weight of bismuth and 0.5 to 5% by weight of tellurium is that bismuth and cadmium improve welding resistance due to their low-temperature sublimation properties.
If it is less than 1% by weight, it has no effect, and if it is less than 1% by weight, bismuth is 20% by weight.
If cadmium exceeds 5% by weight, the melting point of the alloy will be too low, making internal oxidation difficult at high temperatures, and if cadmium exceeds 5% by weight, the welding resistance of silver-bismuth oxide will deteriorate. Indium improves welding resistance due to its thermally stable oxide.
If it is less than 0.5% by weight, there is no effect, and if it exceeds 5% by weight, oxides will accumulate on the contact surface when the contacts are closed, increasing contact resistance and temperature rise. Like bismuth and cadmium, tellurium improves welding resistance through low-temperature sublimation.
If it is less than 0.5% by weight, there is no effect, and if it exceeds 5% by weight, the processability becomes very poor. Based on the above, electrical contacts with sufficiently satisfactory welding resistance can be obtained within the ranges of 20% by weight of bismust, 0.1 to 5% by weight of cadmium, 0.5 to 5% by weight of indium, and 0.5 to 5% by weight of tellurium. material is obtained.

Further, in another electrical contact material of the present invention, in addition to 20% by weight of bismus, 0.1 to 5% by weight of cadmium, 0.5 to 5% by weight of indium, and 0.5 to 5% by weight of tellurium, The reason why group elements are added in an amount of 0.01 to 1% by weight is that when they are dispersed in electrical contact materials, the resulting uniform and fine dispersion of bismuth oxide and cadmium oxide equalizes the consumption caused by discharge. This is because the resistance becomes more stable; if it is less than 0.01% by weight, bismuth oxide and cadmium oxide are not uniformly and finely dispersed, and if it exceeds 1% by weight, their segregation increases and the contact resistance becomes unstable. Become.

(Example and Conventional Example) After melting the material having the composition of Example 1.2 shown in the left column of the table below and making it into atomized powder, it was heated at 600°C, 9 atm,
After 2 days of internal oxidation, this oxidized atomized powder was compressed and sintered, extruded and drawn, then cut and processed into a heel-shaped material.Head diameter: 5. Crane: 1 head height: 1.0 forehead: 1 leg diameter: 2.5111 ．． Leg length 2.5 fin fixed contact, head diameter 4+n, 5 height 1.1++
n, leg diameter 2. A movable contact with Eb+m, leg length 1.611+1° and head height spherical 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 and formed into a chip shape, which was internally oxidized at 600°C and 9 atm for 2 days, then compressed and sintered, and then extruded. After drawing, cutting and processing the heel so that the head diameter is 5 mm and the head height is 1. □m, leg diameter 2.5n.

Fixed contact with leg length 2,511111 and head diameter 4 pieces 1 head height 1
．． 1mm.

Leg diameter 2. A movable contact with a hm+leg length of 1.6 m and a spherical head of 5R was obtained.

However, the bed-type electrical contacts made using 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 a glue bed type electrical contact was assembled into a hinge type relay and an opening/closing test was conducted under the test conditions below, the results shown in the right column of the table below were obtained.

Test conditions Voltage: AC100V 50Hz Current: 40A input, 10A steady load:
Resistance switching frequency = 20 times/min Number of switching operations: Until welding occurs (blank below) As is clear from the table above, the electrical contact materials of Examples 1 to 4 and the bed type electrical contacts are made using the conventional electrical contact materials. It can be seen that compared to the head-type electrical contacts made with 100% or more, the number of openings and closings before welding occurs is greater, the welding resistance is excellent, and the contact resistance is equally low and stable with less 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)

[Scope of Claims] ■) A material consisting of 20% by weight of bismust, 0.1 to 5% by weight of cadmium, 0.5 to 5% by weight of indium, 0.5 to 5% by weight of tellurium, and the balance being silver, and electrical contact materials that are internally oxidized. 2) 20% by weight of bismust, 0.1-5% by weight of cadmium, 0.5-5% by weight of indium, 0.5-5% by weight of tellurium, 0.01-1% by weight of iron group elements, and the balance silver. An electrical contact material which is internally oxidized.