JPS59205437A - Electric contact material - Google Patents

Abstract

PURPOSE:To provide an inexpensive electric contact material for a strong current, obtained by sintering a mixture prepared by mixing silver, nickel, copper and silicon in a powdery form in a specific ratio. CONSTITUTION:A powdery mixture consisting of, on a wt% basis, 10-30% nickel, 1.7-10% copper, 0.5-4.5% silicon and the remainder of silver is baked to prepare an alloy. When this alloy is used as an electric contact material, it is equal to a silver-cadmium alloy in welding resistant characteristics, equal to a silver-nickel alloy with respect to contact resistance and consumption characteristics and the amount of expensive silver to be used can be reduced.

Description

[Detailed description of the invention] B. Field of invention The present invention relates to electrical contact materials for strong currents.

BACKGROUND OF THE INVENTION Conventionally, silver-cadmium oxide alloys have been widely used in the medium to heavy load range. Various improvements have been made to this material from both the compositional and manufacturing viewpoints. ,
It is thought that the welding resistance and abrasion resistance required for electrical contacts have reached their limits for this system1, but in recent years there has been increasing demand for restrictions on the use of cadmium as a pollution problem. Silver-nickel alloys have been used as alternative contact materials to cadmium oxide alloys.

However, silver-nickel alloys are considered to have the same wear resistance as silver-cadmium oxide alloys, but there is a problem in that they are inferior in welding resistance.

C. Purpose of the Invention The present invention was made in view of the above-mentioned problems, and when used as an electrical contact material, the contact resistance and wear amount are equivalent to the above-mentioned silver-nickel alloy, and the welding resistance property is The object of the present invention is to provide an electrical contact material which is superior to a silver-nickel alloy and equivalent to a silver-cadmium oxide alloy, and which can reduce the amount of expensive silver used.

2. Structure and effect of the invention In order to achieve the above object, the present invention sinters a mixed powder of silver, copper and silicon to produce an electrical contact material. % by weight, 1.7 to 10% by weight of copper, 0.5 to 44.5% by weight of silicon, and the balance is silver. The welding resistance properties obtained by preventing arcing (and stabilizing contact resistance) were achieved by mixing silicon with silver.As mentioned above, the range of each component composition was limited as follows. Due to reasons.

Nickel: Added to improve wear resistance. If it is less than 10% by weight, the purpose of addition will not be achieved, and if it is more than 30% by weight, the contact resistance will increase.

Copper: Added to improve contact resistance and nickel dispersibility. If it is less than 1.7% by weight, no improvement in nickel dispersibility will be observed, and if it is more than 10% by weight, welding resistance will deteriorate.

Silicone: Added to improve welding resistance.
If it is less than 0.5% by weight, the purpose of addition will not be achieved;
If it exceeds % by weight, consumption increases and workability deteriorates.

Due to the above-described structure, the electrical contact material of the present invention shows a significant improvement in welding resistance compared to a silver-nickel alloy, and is equivalent to a silver-cadmium oxide alloy. On the other hand, in terms of contact resistance and wear characteristics, it is equivalent to a silver-nickel alloy, and is slightly inferior to a silver-cadmium oxide alloy, but the difference is such that it does not pose much of a problem in practice. Furthermore, although the electrical contact material according to the present invention has almost the same characteristics as the silver-cadmium oxide alloy described above, the amount of silver can be reduced compared to the silver-cadmium oxide alloy, making it suitable as an alternative contact material. It is something.

E. Description of Examples 70% by weight of silver, 20% by weight of nickel, 7.5% by weight of copper,
Each powder containing 2.5% by weight of silicon was mixed using a ball mill.
It was molded into a round bar of 0 mm x length 30 mm, and the resulting molded product was heated to 700 to s o o in an inert gas atmosphere.
It was heated and sintered at 'c for 1 to 2 hours.

This sintered body is heated to 700 to 800°C, then formed into a columnar object with a diameter of 6 mm using an extruder, and then drawn using a countershaft and cut into small pieces of 3 mm in diameter and 6 mm in length to be used as relays. It was used as a built-in test product. Contact resistance, wear amount, and welding characteristics of this sample were measured under the following conditions. The results are shown below.

In addition, as a comparative example, the table shows the comparative amount 1 measured under the same conditions.
(silver 88 - cadmium oxide 12) and comparative amount 2 (silver 7
0-nickel 30).

Test condition sample Relay (2C) each 5-side type Voltage -8C100V -Current
7A Load Resistance load Contact force Initial 20-302 Opening/closing frequency 30 times/min □□□ From the table above, the sample has a large improvement in welding resistance compared to the comparative quantity 21, and compared to the comparative quantity 1. It is comparable in comparison to the It can also be seen that although the contact resistance and amount of wear are slightly inferior to Comparative Amount 1, the difference is such that it does not pose much of a problem in practice.

Claims (1)

[Claims] An electrical contact material made by sintering a mixed powder of silver, nickel, copper and silicon, -'/Care L/210
~30% by weight, 1.7-10% by weight of copper, 0% of silicon
．． 5 to 4.5% by weight, the balance being silver.