JPS60248851A - 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, Mn and Cu to Ag and carrying out internal oxidation. CONSTITUTION:A material consisting of, by weight, 1-20% Bi, 0.1-5% Cd, 0.5-5% Mn, 0.5-5% Cu 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 has 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 is bismast 20% by weight.
and cadmium 0.1-5% by weight, manganese 0.5-5%
It is a material consisting of 0.5 to 5% by weight of copper and the balance 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 0.5% by weight of manganese.
~5% by weight, 0.5~5% by weight of copper, and residual 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, manganese 0.5~
The reason why bismuth and cadmium are set at 5% by weight and 0.5 to 5% by weight is that bismuth and cadmium improve welding resistance due to their low-temperature sublimation properties, and less than 1% by weight bismuth and less than 0.1% by weight cadmium decreases this effect. 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 5% by weight, the welding resistance of silver-bismuth oxide will deteriorate. Manganese is used to improve welding resistance; if it is less than 0.5% by weight, it has no effect, and if it exceeds 5% by weight, layered precipitation occurs, increasing contact resistance and temperature rise. Copper is used to reduce variations in welding resistance by making the oxide particles uniform, and if it is less than 0.5% by weight, it has no effect, and if it exceeds 5% by weight, the welding resistance deteriorates. From the above, 20% bismust by weight
, 0.1 to 5% by weight of cadmium, 0.5 to 5% by weight of manganese, and 0.5 to 5% by weight of copper, an electrical contact material with sufficiently satisfactory welding resistance can be obtained.

Further, in addition to other components of the electrical contact material of the present invention, in addition to 20% by weight of bismast, 0.1 to 5% by weight of cadmium, 0.5 to 5% by weight of manganese, and 0.5 to 5% by weight of copper, 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 internally oxidized at 600°C and 19 atmospheres for 2 days, and this oxidized atomized powder was prepared. The powder is compressed and sintered, extruded and drawn, then cut and processed into a header.Head diameter 5+n+, head height 1.0, weight 9, leg diameter 2.51
1+1. Leg length: 2.5 Crane fixed contacts, head: i flea, 4 dragons, 2 heads, height: 1.14 m, leg diameter: 2.8 m, leg length: 1. Oul.

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 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, the head diameter is 5 mm and the head height is 1. Q+am, leg diameter 2.5 cranes.

Fixed contact with leg length 2.5mm and head diameter 4 pieces, 1 head height 1.1m
m.

Leg diameter 2. b I got a point of contact.

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 Examples 1 and 2 using the conventional material having the component composition shown in the left column of the table below. When a glue head 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: Input 40A, steady 10A Load: Resistance Switching frequency: 20 times/min Switching/closing frequency: Welding salt (hereinafter the margin) As is clear from the table above, Examples 1 to 4 Bent-type electrical contacts made with electrical contact materials have a higher number of openings and closings before welding occurs than conventional electrical contact materials made with bent-type electrical contacts, and have superior welding resistance, and contact resistance is equally low and variable. It can be seen that the value is small and 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] ■) 20% by weight of bismast, 0.1-5% by weight of cadmium, 0.5-5% by weight of manganese, 0.5-5% by weight of copper.
and an internally oxidized electrical contact material, the balance being silver. 2) 20% by weight of bismust, 0.1-5% by weight of cadmium, 0.5-5% by weight of manganese, 0.5-5% by weight of copper, 0.01-1% by weight of iron group elements, balance silver An electrical contact material which is internally oxidized.