JPS6017814B2 - electrical contact materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver-oxide electrical contact material produced by an internal oxidation method.

Silver-cadmium monoxide-based contacts have been widely used as silver-oxide-based electrical contact materials manufactured by internal oxidation methods. Silver-cadmium oxide contacts have a relatively well-balanced combination of low contact resistance, welding resistance, arc wear resistance, and insulation voltage resistance required for contacts, making them suitable for relays, contactor safety breaker, and wiring. Used in small to large current ranges such as circuit breakers and air circuit breakers. However, the use of cadmium in the contact components makes it less desirable during manufacturing. Among silver monoxide-based contact materials, there are contact materials that do not use cadmium, such as those based on silver-tin oxide, silver-indium oxide, silver-zinc oxide, and silver-manganese oxide. Although silver-tin oxide type and silver-manganese monoxide type have welding resistance and dielectric strength and voltage resistance, they have a disadvantage of relatively high contact resistance.

Furthermore, although the silver-zinc oxide system has excellent contact resistance properties, it has drawbacks in welding resistance and dielectric strength properties.

On the other hand, it is desired to reduce the size and improve the performance of switching equipment, as well as to improve the contact performance. The present invention has been made in view of the above points, and provides a silver-zinc oxide based electrical contact material that is highly workable and highly practical, and has high performance welding resistance and insulation resistance. .

Next, the features of the present invention will be described.

The present invention has been developed based on a study on the high current switching and especially the welding resistance and insulation resistance properties of the contacts.The present invention has been developed based on the results of the study on the high current switching and especially the welding resistance and insulation resistance properties of the contacts. By internally oxidizing an alloy containing 0.001 to 2% bismuth and 2% or less iron group elements, it has excellent workability and excellent contact resistance, and can achieve welding resistance and insulation resistance. . As is well known, the silver-zinc oxide internally oxidized alloy is an alloy in which zinc oxide is easily dispersed parallel to the contact surface to form an oxide agglomeration zone. For this reason, the alloy has poor thermal conductivity, and is prone to wear and welding caused by arc heat when opening and closing the contacts. On the other hand, "Ag-zinc oxide indium monoxide internal oxidation alloy is a combination of Zn○ and ln203 that forms a composite oxide and thermally stabilizes the oxide, reducing contact wear and improving insulation properties. but,
When the amount of zinc and indium increases, an agglomerated zone of oxide is formed on the contact surface layer during internal oxidation, making internal oxidation extremely difficult.

In the present invention, as a result of various studies on elements that can increase the amount of dispersed oxide by utilizing the stabilization of the oxide by the combination of zinc and indium, it was discovered that bismuth is effective. Furthermore, iron group elements promote this effect and
Furthermore, it was also discovered that it has the effect of improving processability. In the alloy of the present invention, the lower limit of zinc is set to 5% because if the content is less than this, the amount of oxides is small and the welding resistance is poor.

The reason why the upper limit of zinc is set at 15% is based on the fact that if it exceeds this value, internal oxidation becomes particularly difficult during alloy production. The lower limit of bismuth is set at 0.001% because it has little effect in preventing agglomeration of dispersed oxides and has little effect on improving welding resistance and insulation resistance. The upper limit is set at 2% because if it exceeds this value, processing becomes extremely difficult and internal oxidation becomes unstable. If the lower limit of indium is 0.5 or less, the amount of complex oxide formed is small and the effect is small, and if the upper limit is 10 or more, internal oxidation becomes unstable and the price becomes higher. The reason why the content of iron group elements is set to be 2% or less is that if the content exceeds this value, these elements will be non-uniformly dispersed in the iron, making them more likely to cause agglomeration, thereby deteriorating the welding resistance and insulation resistance. Moreover, if it is less than 0.01%, the effect of preventing agglomeration of dispersed oxides is small.

Next, in order to further clarify the characteristics of the electrical contact material of the present invention, typical examples of specific electrical contacts will be described.

An alloy having the alloy composition shown in Table 1 was melted and cast, and after wire drawing, it was oxidized in 700 qo air to obtain a wire.

The oxidized wire was processed by heating to obtain a glue pet contact with a head diameter of 5 ribs, a rib thickness of 1.4, a foot diameter of 2.5, a foot length of 2.5, and a rib contact surface curvature of 3. This rivet-shaped contact was assembled into a commercially available safety breaker, and an overload test and a short circuit test were conducted under the conditions shown in Table 2, and the dielectric strength voltage and the number of times until welding were measured by measuring the resistance between the terminals.

The results are shown in Table 3. Also, for comparison, Ag-10
%Cd○ contact was added. In addition, an alloy having the alloy composition shown in Table 4 was melted, cast, wire-drawn, and then oxidized in air at 70,000 ml to obtain a wire. By header processing the oxidized wire, we obtained a glue pet contact with a head diameter of 5 ribs, a thickness of 1.4 ribs, a foot diameter of 2.5 willow, a foot length of 2.5 willow, and a contact surface curvature of 3. . This rivet contact was evaluated under the conditions shown in Table 2.
Obtained the results in the table. Table 1 Table 2 Table 3 Table 4 Table 5

Claims (1)

[Claims] 1. In a silver-oxide composite alloy produced by an internal oxidation method, the weight ratio of zinc is 5 to 15% and indium is 0.5 to 1%.
An electrical contact material characterized by containing 0.001% to 2% of bismuth. 2 In a silver-oxide composite alloy manufactured by internal oxidation method, zinc is contained in a weight ratio of 5 to 15% and indium is contained in a weight ratio of 5 to 15%.
0%, bismuth 0.001-2% and iron group elements 0.0
An electrical contact material characterized by containing 1 to 2%.