JPS6026631A - Electrical contact material - Google Patents

Abstract

PURPOSE:To improve the welding resistance of a sintered Ag-Ni material having a specified composition and to make the material harmless by adding a specified amount of In to the material. CONSTITUTION:The composition of a sintered material for an electrical contact is composed of 10-30wt% Ni, 1.7-5wt% In and the balance Ag with inevitable impurities. Fine powders of said elements having 0.5-20mum particle size are used as starting materials. They are blended in the prescribed ratio, press- molded, and sintered to 700-800 deg.C for 1-20hr in an inert gaseous atmosphere to manufacture said sintered material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrical contact materials, and in particular to a sintered material for electrical contacts that has excellent welding resistance and is harmless.

Conventionally, A g Cd O-based sintered materials, which have been widely used as electrical contact materials in the medium load range, have excellent contact and resistance properties, but because they are made from harmful Cd, their manufacturing process and use are difficult. There is a possibility that it becomes dust containing Ccl, which may cause pollution, and it also has the disadvantage of being high in cost because it tends to contain a large amount of Ag.

ability, Ag as a harmless electrical contact material that does not contain Cd
Although Ni-based sintered materials have been put into practical use, this AgN:-based sintered material has a problem in that it is inferior in welding resistance compared to Ag Cd O-based materials.

The present invention improves the welding resistance, which is a drawback of conventional sintered XgNI-based 4.4 materials, and provides an inexpensive electrical contact material that has contact performance equivalent to or better than that of AgCd0-based electrical contact materials. The purpose is to

The gist of the present invention is that N i 1 (1-30%, I n
1. 7-5%, the remainder being in the sintered material for electrical contacts consisting essentially of Ag and unavoidable impurities.

To explain the reason why the composition of the sintered material for electrical contacts according to the present invention is limited as described above, Ni is added to improve the consummability of i;
The effect cannot be obtained in the case of unconventional conditions, and if it exceeds 30%, the contact resistance increases, so it was set at 10 to 30%. Also,
In is added to stabilize the contact resistance and reduce arcing.If the added amount is less than 1.7%, the effect of the addition will not be fully achieved, and if it exceeds 5%, the contact resistance will decrease. 1.7 to 5% because it increases and the welding resistance deteriorates.
And so.

The sintered 4.A material for electrical contacts according to the present invention having the above-mentioned composition has greatly improved adhesion resistance compared to conventional AHNi-based sintered materials, and has almost the same adhesion resistance as AgCd0-based sintered materials. show. In addition, regarding contact resistance and wear resistance, 1X
It is almost the same as the BNi-based material, and is slightly inferior to the A B Cd O-based material, but the difference is not so great as to cause a practical problem. Moreover, the sintered material for electrical contacts according to the present invention is
Since it has a lower Ag content than AgCdO-based sintered materials, it can be manufactured at low cost, and it does not contain harmful Cd, so it does not cause pollution.

The sintered material for electrical contacts uses fine powders of Ag, N1, and In as raw materials, which are mixed in a predetermined ratio, and after being press-molded, it is heated at 700-800°C in an inert gas atmosphere.
It is manufactured by a method of sintering for 20 hours. Generally, when In or the like is dissolved in Ag, the resistance increases slightly compared to pure AB, but this does not pose a particular problem as an electrical contact material.

Further, after sintering, it is preferable to subject the obtained sintered body to re-drawing such as sizing and coining.

The raw material powder is usually 0.1 to 103μ, preferably O, S = 2 (1μ), but commercially available powders may be used as they are.

Examples of the present invention will be described below.

Example raw material powder)\8 powder (average particle size: ], 08μ)
) wt%, Ni powder (average particle size: 2.2 μ), 25 wt%, In powder (average particle size: 5 μ), 5 wt%, and uniformly mixed in a ball mill.
Diameter 20 man, length 3cm+ under pressure of L/cm'
n, and the resulting molding ratio was 75% in an inert gas atmosphere.
The mixture was heated and sintered at 0'C for 2 hours to obtain a sintered body for electrical contacts. This sintered body was heated to 700 to 800°C, and after forming one rod-shaped body with a diameter of 6 nm+m using an extrusion stone, the contacts obtained by processing with a wire drawing machine were hooked into a relay.
This was used as a sample.

Comparative Example 1 Using powders of 88 and CdO as raw materials, a sintered 14 (Ag]22%Cd was obtained in the same manner as in the example and used as a contact, and this was incorporated into a relay to make a test product.

Comparative Example 2 Using the ABu and Ni powders used in the examples as raw materials, these were mixed in a weight ratio of 70% Ag and 30% Ni, and AgNi-based sintered wood was obtained in the same manner as in the examples and used as a contact. This was assembled into a relay and used as a sample.

The contact resistance, abrasion resistance, and welding characteristics of the relays obtained in the Examples and Comparative Examples were measured under the following conditions.The results are shown in the table. It is expressed as the number of relays whose contact force was 5 g or less when the relay was opened and closed twice.

[Test conditions 1 Samples: 5 relays (2C) each Voltage: AClooV Current near A Load: Resistance load contact crab Initial 20-30g Opening/closing frequency: 30 times/min [Table 11 Contact resistance Wear resistance Welding life (b) Ω) (pieces) (width) Example 39 2 42 Comparative example 1 36 0 45 Comparative example 2 G'i 1 34 As is clear from the results shown in Table 1, the electrical contact material according to the present invention The welding resistance was significantly improved compared to that of Comparative Example 2, and the properties were equivalent to those of Comparative Example 1. In addition, it can be seen that although the contact resistance and wear resistance are slightly inferior to those of Comparative Example 1, the difference is such that it does not pose much of a problem in practical use.

Patent Applicant Den Tateishi (Iku Co., Ltd. Agent Patent Attorney Seihaku Ho and 2 others Procedural Amendment (Own ship 1. Indication of the case 1985 Patent Application No. 1349660003 Relationship to the case) Patent Applicant Address: Kyoto, ■4 Agent, 10-4 Kaen Dodo-cho, Ukyo-ku, Kyoto City

Claims (1)

[Claims] (1) A sintered material for electrical contacts consisting of 10-30% Ni, 1.7-5% In, and the remainder substantially Ag and unavoidable impurities.