JPH0689421B2 - Electrical contact material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides Ag- which has high mechanical strength and is excellent in welding resistance.
The present invention relates to a Ni-based alloy electrical contact material.

[Conventional technology]

Conventionally, various materials have been used as electric contact materials, but among them, Ag-Ni contacts are widely used in place of Ag because of their low contact resistance and low consumption.

In addition, since Ag-Ni is easy to process and spot weld, it is possible to automate the work of fixing it to a base material, etc., which reduces the assembly cost and stabilizes the quality.

[Problems to be solved by the invention]

However, Ag-Ni has a problem that its use range is limited to a relatively small current region because its mechanical strength is small and welding resistance is inferior as compared with Ag-oxide systems such as Ag-Cdo.

In recent years, devices and equipment have been aiming for weight reduction, downsizing, and large capacity, but also from this point, there is a problem that the Ag-Ni-based welding resistance is poor.

As a method of solving these problems, we are trying to improve the characteristics by adding various metal oxides, nitrides, carbides, borides, etc. to the Ag-Ni alloy. Ag-Ni alloys are produced by powder sintering because there is almost no solid solubility between Ag and Ni. The above-mentioned attempts have been made with the addition of metal oxides, nitrides, carbides and borides. The size and dispersion of the particles are problematic, and additive particles are always present on the contact surface. If the particles are coarse or in a poorly dispersed state, the contact resistance becomes extremely unstable, or the contact resistance becomes high, impairing the stable contact property that is the original feature of Ag-Ni system, and the welding resistance due to temperature rise etc. Will be lowered.

There is also a problem that the workability and spot weldability, which are the characteristics of Ag-Ni alloys, are impeded by the mixture of various additives, and an automated line cannot be built.

An object of the present invention is to improve the mechanical strength and the welding resistance without deteriorating the workability and spot weldability, which are the characteristics of Ag-Ni alloys, and to widen the operating current range.

[Means for solving problems]

The present invention achieves the above object by mixing and firing Ni powder containing 5 wt% to 25 wt% of Ni and Ag alloy powder containing 0.1 wt% to 5 wt% of at least one of Bi and Ga. It is characterized in that a diffusion alloy layer of at least one of Bi and Ga and Ni powder is formed on the outer peripheral portion of the Ni powder in the alloy structure of the alloy formed by binding.

[Action]

According to the present invention, 0.1 to 5% by weight of at least one metal selected from Bi and Ga is dissolved with Ag to form an alloy powder by a melt spraying method (atomizing), and the alloy is formed and then the alloy is formed. The powder and the Ni powder of 5% to 25% by weight are sufficiently heated and sintered at a predetermined temperature.

After that, normal processing is performed to disperse Ni in the Ag alloy matrix.

At this time, it is important to sufficiently diffuse the solute metal Bi, Ga and Ni particles in the matrix by sintering and heating after molding, and the conventional one in which Ni is simply dispersed in the Ag matrix. The mechanical strength is improved and the welding resistance is significantly improved as compared with, and Ag-Ni improves the material strength because a diffusion alloy layer is formed on the outer periphery of the Ni grain through the element that forms a solid solution with Ni. be able to.

〔Example〕

 Examples of the present invention will be described below.

Ag-0.1Ga, Ag-5Bi, Ag-3Ga-0.5Bi, Ag-1Ga-3Bi, Ag-
An alloy having a composition ratio of 0.05Ga-0.1Bi and Ag-0.7Ga-0.05Bi is made into powder by an atomizing device and sieved to powder of 300 mesh or less.

85% by weight of each of these alloy powders and 15% by weight of Ni and a powder of 300 mesh or less are mixed by using a V-type mixer.
(Ag-0.1Ga) -Ni, 85 (Ag-5Bi) -Ni, 85 (Ag-3Ga-
0.5Bi) -Ni, 85 (Ag-1Ga-3Bi) -Ni, 85 (Ag-0.05Ga
-0.1Bi) -Ni, 85 (Ag-0.7Ga-0.05Bi) -Ni was prepared.

These are molded to a diameter of 50φ and a length of 120 mm at a pressure of 2.5 t / cm ² , and the molding material is heated and sintered in a non-oxidizing atmosphere at a predetermined temperature for a predetermined time to obtain a billet.

These are heated in a non-oxidizing atmosphere and the diameter is 10φ with an extruder.
And a wire rod having a diameter of 6φ using a wire drawing machine.

A revetted contact material having a diameter of 6φ is formed from the wire.

The contact resistance, the amount of wear, and the number of weldings of the rivet-shaped contact material produced as described above were measured under the following conditions using an ASTM tester. The results are compared with Table 1.

Incidentally, 85Ag-Ni is listed as a conventional example.

[Effects of the Invention] As described above, according to the present invention, Ni is decomposed in a base material alloyed with Ag in an amount of addition of at least one of Bi and Ga to form a diffusion alloy layer on the outer peripheral portion. This improves the material strength.

Also, by attaching Bi and Ga, which have a relatively high oxygen affinity, these oxides are easily generated at the contact interface of the contact, and the sublimation of this oxide causes a cooling phenomenon of the arc, which results in welding resistance, Wear resistance is improved.

From the above, the effect can be expected as an improvement of the characteristics of the conventional Ag-Ni-based electrical contact material.

Claims (1)

[Claims] 1. Ni powder containing 5% to 25% by weight of Ni and Bi, Ga
Of at least one of Bi and Ga and the Ni powder in the outer periphery of the Ni powder in the alloy structure of the alloy formed by mixing and sintering the Ag alloy powder containing at least one of 0.1% to 5% by weight of An electrical contact material characterized in that an alloy layer is formed.