JPS58207348A - Electrical contact material for sealing - Google Patents

Abstract

PURPOSE:To obtain a composite electrical contact material for sealing consisting of a prescribed percentage of molybdenum 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 1-20wt% molybdenum nitride in copper. Copper powder is mixed with molybdenum 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 resistances, 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 thread alloy, gold thread alloy,
Composite electrical contact materials made of noble metals such as baradium alloys, for example, 12% by weight of silver cadmium oxide, have been widely used in various directions as they exhibit excellent contact characteristics in the small to medium current range. However, with the recent miniaturization of electrical and electronic devices, the contact characteristics required of electrical contact materials have become more severe, and conventional composite electrical contact materials of silver oxidation strength and thread have poor welding resistance. , it has become unusable. There is a need for an electrical contact material for encapsulation that has even better welding resistance.

On the other hand, in order to reduce the use of precious metals and provide an inexpensive contact material (c(1)), we focused on copper, which has a higher electrical conductivity than silver and has a higher melting point than silver, and used this as a contact material with a 4° angle with the mother alloy. It's an attempt to do that! I met.

When copper is used as a contact material, there is a problem with the corrosion resistance of copper, but this problem is solved by using copper in a vacuum or neutral gas, and there is no problem compared to using precious metals as the mother alloy. This shows that it has an inferior calendar characteristic. In particular, nitrides have a large melting point of A& materials, and when A melting point materials such as titanium nitride or ruconium nitride are used as a dispersion reinforcing material for copper, the wear amount is small and the welding force is 7. It shows. However, due to the melting point of the material, the composition changes little due to melting, evaporation, etc. As the contact is repeatedly opened and closed, an agglomerated layer of dispersion reinforcing material is generated on the surface layer, resulting in a roaring and unstable contact resistance. It has a tendency.

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 contains molybdenum nitride 1 in steel.
The reason for adding molybdenum nitride to the steel is that molybdenum nitride has a temperature of 1168°C.
This is because it has an unstable property of being dissociated in the process, 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 molybdenum nitride added to the steel is set at 1 to 20% by weight because if it is less than 1% by weight, the copper base will not be sufficiently strengthened. Good results cannot be obtained regarding properties. Moreover, if the composition exceeds 20% by weight, processing becomes difficult and the electrical 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 welding resistance.

〔Example〕

(3) After mixing copper powder with an average particle size of 4 μm and molybdenum nitride in a V-type mixer for 3 hours, the powder was filled into a crucible and sintered and compressed repeatedly until it reached a predetermined density, and the material was hot extruded. This was made into a wire rod using a wire drawing machine, and then processed using a header machine to produce 4 wire rods with a head diameter of 4φ and a head height of 1.1 having the composition shown in the table below.
A rivet type contact with a leg diameter of 2.8 φ and a leg length of 1.6 m was obtained.

[Conventional Example 1] Copper powder with an average particle size of 4μ and titanium nitride were mixed in a ■ type mixer.
After mixing for a period of time, the powder is filled into a crucible, sintered and compressed repeatedly until it reaches a predetermined density, and then processed using a header machine to produce a powder with a head diameter of 4゛φ and a head height of 1.1 mm, having the composition shown in the table below.
A rivet type contact with a leg diameter of 2.8φ and a leg length of 1.6 mm was obtained.

[Conventional example 2] A silver cadmium alloy is cast, drawn, drawn, and made into rivets using a header machine with a head diameter of 4φ, a head height of 1.1mm, a leg diameter of 2.8φ, and a leg length of 1.6fi. After molding into a shape, internal oxidation was performed at 5 atm and 800°C, and 12% by weight of silver cadmium oxide was added.

(4) However, the electrical contacts of Example 1 and Conventional Example 1.2 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. The results shown in the right column were obtained.

Test conditions Voltage ^, C, 100V 50Hz Current Closing current 40A, steady current 10A Opening/closing frequency
20 times/min load Resistance switching times Atmosphere until welding occurs Nitrogen atmosphere (5) As is clear from the values in the right column of the table above, the electrical contacts made using the electrical contact material of the example were as follows: Conventional Example 1.2 It can be seen that the wear resistance and Ik4/8 adhesion are superior to, but not inferior to, electrical contact key materials, and the material exhibits stable low contact resistance.

As detailed above, the composite electrical contact material according to the present invention has superior welding resistance and copper wear resistance as well as excellent contact resistance compared to conventional silver-cadmium oxide and titanium steel electrical contact materials. Because of its characteristics, it can be said to be an innovative electrical contact material for encapsulation that has contact performance that can withstand the harsh operating conditions associated with the recent miniaturization of electrical and electronic equipment.

Applicant: Tanaka Kikinzoku Kogyo Co., Ltd. (6)

Claims (1)

[Claims] An electrical contact material for encapsulation that contains 1 to 20% molybdenum nitride in terms of bundle ratio and the balance is copper.