JPH02226619A - Electric contact material and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an electric contact material of excellent electric connection that does not generate adhesion nor abrasion by depositing an Ag or Ag alloy coating layer, and a thin layer of Au, Pd, Ru, Rh, or of alloy thereof, on the surface of a metal filament substrate. CONSTITUTION:Cu, Cu alloy, Cu coated steel material, or Al material, or Ni, Fe, or alloy thereof are used for a base material, on which 0.5mum or more of Ag or of alloy such as Ag-Cu, Ag-Sb, etc., is formed by electroplating and so on. On the surface, a thin layer of Au, Pt, Ru, Rh or of alloy thereof is electroplated by 0.001-0.1mum. The thin film is effective when it is not less than 0.001mum, and the generation of adhesion and abrasion due to the contact between Ag or alloy thereof is prevented, forming an excellent electric contact.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electrical contact material and a method for manufacturing the same, and more specifically, exhibits excellent sliding properties and stable electrical connectivity when used as an electrical contact. The present invention relates to an electrical contact material and a manufacturing method thereof.

(Prior art) Generally, the surface of the base material of various metal wires is coated with Ag or Ag.
In addition to the properties possessed by the base material, materials coated with alloys have
Ag or Ag alloys exhibit corrosion resistance, solderability, electrical connectivity, etc., which are unique to Ag or Ag alloys, so they have been used for various purposes.

For example, an Ag-coated Cu association material in which an Ag coating layer with a thickness of 0.5 to 20 μm is formed on a Cu alloy strip;
In addition to the excellent mechanical properties of the alloy, it is known as an economical high-performance conductor with excellent corrosion resistance, solderability, electrical connectivity, etc., and is used as a component and lead in the electrical and electronic equipment field. Widely used as a material. This material is also used as a material for electrical contacts.

(Problems to be Solved by the Invention) By the way, a switch is constructed by combining a fixed contact and a movable contact. Both of these contacts are made of a material in which a coating layer of Ag or Ag alloy is formed on the surface of the base material.

However, as the number of contacts between these two contacts increases, the switch actuation force begins to decrease and the contact resistance increases, leading to a decrease in the switch function and eventually shortening the service life of the switch. This phenomenon is caused by the adhesion of Ag or Ag alloy on the contact surfaces of both contacts, and as the adhesion progresses, the switch actuation force decreases and the coating layer of Ag or Ag alloy on the contact surfaces is peeled off. This is because contact resistance increases as the base material is exposed.

As a means to prevent such adhesive wear phenomena, it is known that the contact surface is made of a material that is a combination of different metals such as Au-Ag, Pd-Ag, and AgPd-Ag. . However, since this method uses expensive precious metals such as those mentioned above, the cost of the contact point increases significantly, and its application is inevitably limited to a very narrow range.

In general, many electrical contacts require stable electrical connectivity, and in order to stabilize this electrical connectivity, both initially and after time has passed, it is necessary to It is necessary to reduce fluctuations in contact resistance at the contact surface, to have good sliding properties on the contact surface, to reduce wear damage, and to have excellent corrosion resistance.

The object of the present invention is to provide an electrical contact material that does not cause the adhesive wear phenomenon described above and has excellent electrical connectivity, and a method for manufacturing the same at low cost.

(Means/effects for solving the problem) In order to achieve the above-mentioned object, the present invention includes a metal filament base material, and Ag or Ag formed by coating the surface of the metal filament base material. An alloy coating layer and Au formed by coating the surface of the coating layer.

There is provided an electrical contact material characterized by comprising a thin layer of Pd, Ru, Rh or an alloy thereof, and the surface of the metal wire base material is plated or cladded with Ag or an Ag alloy. After forming a coating layer, Au and Pd are deposited on the surface of the coating layer.

An electrical contact material is provided that is characterized in that it is plated with Ru, Rh, or an alloy thereof to form a thin layer.

First, in the present invention, the metal wire base material used is
Cu, various Cu alloys; composite substrates made by coating different materials with Cu or Cu alloys, such as Cu-coated steel and Cu-coated aluminum; or [.

Examples include Fe and a base material made of an alloy thereof.

A coating layer of Ag or Ag alloy is formed on the surface of this base material. The Ag alloy used is ^g-Cu alloy,
Examples include Ag-5b alloy.

This coating layer is formed by applying an electroplating method or a cladding method. The thickness of the formed coating layer is usually 0.
It is sufficient that the layer thickness is 5 μm or more, and the operating conditions in the electroplating method and the cladding method are controlled so that such a layer thickness is obtained.

The material of the present invention further has Au, PL, Ru, Rh or Au-
Thin layers of these alloys, such as Ag and Au-Pd, are laminated.

This thin layer is thought to have the effect of suppressing the phenomenon in which the Ag of the underlying coating layer adheres to each other during contact operation. In other words, when Ag or Heg alloys come into contact with each other, they may cause adhesive wear as described above, reducing the switch actuation force, or they may be peeled off from the base material, exposing the base material and reducing the contact resistance between the contacts. However, it is thought that the presence of this thin layer between both contacts suppresses the above phenomenon.

Such an effect begins to appear when the thickness of the thin layer is 0.001 μm or more. However, even if it is thicker than 0.1 μm, the effect will reach saturation and expensive precious metals will be wasted, which is not economical.
It is preferable to set it in the range of 0.01 to 0.1 μm.

The thin layer is formed by electroplating. The plating bath to be used, plating conditions, etc. may be appropriately selected in consideration of the type of thin layer, the thickness to be formed, etc.

(Embodiments of the invention) Examples 1 to 9. Comparative Examples 1 to 3 A brass plate with a thickness of 0.3 m, a width of 3 m, and a length of 150 m was subjected to alkaline degreasing, water washing, and pickling to clean the surface.

Next, the surface of this brass plate was subjected to Ag strike plating to form Ag plating coating layers having various thicknesses as shown in Table 1.

Next, a thin plating layer made of the metal or alloy shown in Table 1 and having the thickness shown in Table 1 was formed on the surface of the obtained Ag-plated brass plate.

For each of the obtained materials, changes over time in the dynamic friction coefficient and microdynamic friction contact resistance were investigated using the following specifications.

Dynamic friction coefficient: An Ag rod with a head radius of 5 m is brought into contact with the above thin plating layer, and a load of 50 g is applied to the sliding path. Repeated sliding over a distance of 110 m, 10 times.

50 times, 100 times, 200 times, 500 Measure the coefficient of kinetic friction in each case. Fixed.

Microdynamic friction contact resistance: Ag whose head radius is 5 mm
A rod was brought into contact with the thin plating layer, a load of 100 g was applied, and the current applied was IA.
Repeated sliding is performed over a sliding distance of 0.1 m, and the number of times of sliding is 5,000, 20,000, 50,000, and 100,000 times.

Contact resistance in each case of 200,000 times Measure.

The above results are collectively shown in Table 1.

(Blank below c) (Effect of the invention) As is clear from the above explanation, the materials in the present invention are:
It has a small coefficient of dynamic friction and excellent sliding properties, and the contact resistance changes little over time and is stable.

This is an effect based on the formation of a thin noble metal plating layer on the surface of the coating layer of Ag or Ag alloy. ) is clear compared to the characteristics of

Moreover, since the thickness of the thin plating layer is relatively thin, the manufactured material is relatively inexpensive. As described above, according to the present invention, an electrical contact material having stable electrical connectivity can be provided at low cost, and its industrial value is great.

Claims (4)

[Claims] (1) a metal filament base material, a coating layer of silver or silver alloy formed by coating the surface of the metal filament base material, and gold or platinum formed by coating the surface of the coating layer; An electrical contact material comprising a thin layer of rubidium, rhodium or an alloy thereof. (2) The electrical contact material according to claim 1, wherein the thin layer has a thickness of 0.001 to 0.1 μm. (3) After forming a coating layer on the surface of the metal wire base material by plating or cladding with silver or silver alloy, gold, platinum, rubidium, rhodium or an alloy thereof is applied to the surface of the coating layer. 1. A method for producing an electrical contact material, which comprises forming a thin layer through plating. (4) The manufacturing method according to claim 3, wherein the thin layer has a thickness of 0.001 to 0.1 μm.