JPS58207345A - Electrical contact material for sealing - Google Patents

Abstract

PURPOSE:To obtain a composite electrical contact material for sealing consisting of a prescribed percentage of magnesium nitride and the balance copper, superior to a conventional copper-nitride type composite electrical contact material in contact performance, and having especially stable low contact resistance. CONSTITUTION:This composite electrical contact material for sealing contains 1-15wt% magnesium nitride in copper. Copper powder is mixed with magnesium nitride powder in a V-type mixer for a prescribed time. The powdered mixture is filled into a crucible, and it is repeatedly sintered and compressed until a prescribed density is provided. The resulting material is hot extruded, formed into a wire rod with a drawer, and worked with a header to obtain a rivet type contact or the like. This composite electrical contact material is not at all inferior to a conventional copper-titanium nitride type electrical contact material or the like in welding and consumption resistance, and it has superior contact resistance characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an encapsulated electrical contact material based on a shell compound. Conventionally, electrical contact materials for encapsulation include silver alloys, gold thread alloys,
Noble metals such as palladium-based alloys, such as Jll [cadmium 121! Composite electrical contact materials consisting of 1% have been widely used in various fields as they exhibit excellent contact characteristics in the small to medium current range. However, with the recent miniaturization of electrical equipment and electronic devices, the contact characteristics required of electrical contact materials have become more severe, and conventional composite electrical contact materials of silver cadmium oxide threads have poor welding resistance. I can no longer use copper. For these reasons, there is a demand for electrical contact materials for encapsulation that have excellent welding resistance.

On the other hand, in order to reduce the use of precious metals and provide inexpensive contact materials (1), we focused on copper, which has the second highest electrical conductivity after silver and has a melting point higher than silver, and attempted to use contact materials using copper as a mother alloy. Attempts have begun to be made.

When copper is used as a contact material, corrosion resistance of copper becomes a problem, but this problem is solved by using copper in a vacuum or neutral gas, and it is no more expensive than using precious metals as the mother alloy. It shows comparable characteristics. In particular, many nitrides have a low melting point, and when a high melting point material such as titanium nitride or zirconium nitride is used as a dispersion reinforcing material for copper, the amount of wear is small and it also exhibits excellent welding strength. However, with materials such as these whose melting point is low and whose composition changes little due to melting, evaporation, etc., as the contacts are repeatedly opened and closed, an agglomerated layer of dispersion reinforcing material is generated on the surface layer (unstable contact resistance). It has a tendency to bring about.

The present invention was made in view of the above circumstances, and has superior contact performance than conventional copper-nitride composite electrical contact materials.
In particular, we aim to provide a composite electrical contact material that has stable and low contact resistance (2).

The electrical contact material for encapsulation of the present invention is made by adding 1 to 15% by weight of magnesium nitride into the shell.The reason why magnesium nitride is added to the shell is that magnesium nitride is
This is because it thermally decomposes at 00°C, has unstable properties, and has the function of preventing the formation of nitride agglomerated bands on the contact surface and stabilizing the contact resistance.

In the electrical contact material of the present invention, the reason why the magnesium nitride added to the body is 1 to 15% by weight is because if it is less than 1% by weight, the copper base will not be sufficiently strengthened. Good results cannot be obtained regarding properties.・
Furthermore, if the composition exceeds 15% by weight, processing becomes difficult and the conductivity of the material becomes low, making it impossible to obtain good results. For the above reasons, the compositions described in the claims are limited.

Furthermore, when these copper-nitride materials are used in a nitrogen atmosphere, they exhibit even better anti-welding properties.

(3) [Example] After mixing copper powder with an average particle size of 4μ and magnesium nitride in a V-type mixer for 3 hours, the powder was filled into a crucible and sintered and compressed repeatedly until a predetermined density was reached.The material was then hot heated. I pushed it out. This is made into a wire rod using a wire drawing machine, and then processed using a header machine to form a wire rod with a four-part diameter of 4φ and *IIM.
Lihesoto-type contacts with a diameter of 2.8 φ and a leg diameter of 1.6 mm were obtained.

(Conventional example 1) Copper powder with an average particle size of 4μ and titanium nitride were mixed in a
After filling the crucible with the mixed I powder for a long time and repeating sintering and compression until it reaches a predetermined density, it is processed using a soda machine and has the composition shown in Table F, head diameter 4φ dragon, head A 1.1 crane, A glue bent type contact with a leg diameter of 2.8φ and a leg length of 1.6 am was obtained.

[Conventional example 2] A string of cadmium alloy is cast, drawn, and loaded, and then the head diameter is 4φ by a header machine.
After molding into the shape of a crane glue bed (4) with a leg diameter of 2.8φ and a leg length of 1.6 days, it was internally oxidized at 5 atm and 800°C to obtain 12% by weight of silver cadmium oxide.

However, the electrical contacts of the above embodiment and conventional examples 1 and 2 were subjected to opening and closing tests under the following test conditions, and the number of openings and closings until welding occurred was measured, as well as the contact resistance and wear and tear. The results shown are obtained.

Test conditions Voltage A, C, 100V 50Hz current Closing type FI 40A, steady current 10A Switching frequency 20 times/min Load Resistance switching number of times Atmosphere until welding occurs Nitrogen atmosphere (5) It is clear from the numbers in the right column of the table above As shown, the electrical contacts made with the electrical contact materials of Examples 1 and 2 have superior abrasion resistance and welding resistance as well as stable low contact resistance compared to the electrical contact materials of Conventional Examples 1 and 2. I understand that.

As detailed above, the composite electrical contact material according to the present invention has superior welding resistance and abrasion resistance as well as excellent contact resistance properties compared to conventional electrical contact materials of silver-cadmium oxide and chambered titanium yarn. Due to the nature of recent electrical and electronic V
It can be said to be a temporary electrical contact material for encapsulation with contact performance that can withstand the harsh operating conditions associated with the miniaturization of devices.

Applicant: Tanaka Kikinzoku 1. Industry Co., Ltd. (6)

Claims (1)

[Claims] An electrical contact material for encapsulation that contains 1-15% magnesium nitride and the balance is copper.