JPH1040763A - Sealed electric contact material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress sticking between contact points and provide a long operation life by producing a sealed electric contact material constituted of a substrate and a coating of a CU-In alloy, a Ag-In alloy, or a Cu-Zn alloy on the substrate. SOLUTION: An electric contact material is constituted of a Fe-Ni alloy contact substrate and a coating layer with 0.1μm thick or thicker on the substrate and the coating layer contains 1-30 atomic % of In and the balance Cu or Ag. Or, the electric contact material is constituted of a Fe-Ni alloy contact substrate and a coating layer with 0.1μm thick or thicker on the substrate and the coating layer contains 1-30 atomic % of Zn and the balance Cu. Of this sealed electric contact material, Cu or Ag works to stabilize the contact resistance. On the outer hand, since Cu or Ag has sticking property, Cu or Ag easily tends to cause opening or closing failure. Indium (In) improves the sticking property and that is the same in the case Cu is used as the first element and Zn as the second element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed electrical contact material suitable for a reed switch and the like, which is inexpensive and hardly causes adhesion between contacts.

[0002]

2. Description of the Related Art An encapsulated electrical contact material is used, for example, by sizing a contact having a predetermined shape and mounting it on a contact inside a glass enclosure made of a vacuum or an inert atmosphere. Conventionally, the encapsulated electric contact material is prepared by plating a substrate of Ag, Au, Cu or the like on a base material of an Fe-Ni alloy, and having high conductivity, high hardness, high melting point, and excellent wear resistance. R
Those coated with h or Ru have been frequently used. The underplating improves the adhesion between the substrate and the coating layer.

However, the encapsulated electrical contact material is expensive because it covers expensive Rh or Ru. Therefore, without using expensive Rh, Ru, etc., Ag, A
When u, Cu, or the like is used as the contact, Ag, Au, Cu, or the like stabilizes the contact resistance, but has a problem in that it exhibits adhesiveness, so that open / close failure is likely to occur, and as a result, the operating life is shortened. An object of the present invention is to provide a sealed electric contact material which is inexpensive and hardly causes adhesion between contacts.

[0003]

According to the first aspect of the present invention,
A coating layer having a thickness of 0.1 μm or more is formed on the contact substrate, wherein the coating layer contains 1 to 30 at% of In, and the rest is Cu or Ag.
An encapsulated electrical contact material characterized by comprising:

According to a second aspect of the present invention, the thickness of the contact
A coating layer of 0.1 μm or more is formed, and the coating layer contains Zn.
An encapsulated electrical contact material containing 1 to 30 at%, with the balance being Cu.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the material of the contact substrate is not particularly specified, and any material conventionally used as a substrate for an encapsulated contact, for example, Fe,
Ni, Co, Ni-Fe alloy, Co-Fe-Nb alloy, Co-Fe-V alloy, Fe-Ni-Al-Ti alloy, Fe-Co-Ni alloy, carbon steel, phosphor bronze, Nickel silver, brass, stainless steel, Cu-Ni-Sn alloy, C
A u-Ti alloy or the like can be used. In forming the coating layer on the contact base material, an intermediate layer for preventing diffusion of constituent elements may be provided between the contact base material and the coating layer.

According to the first aspect of the present invention, Cu or A
g (first element) functions to stabilize the contact resistance.
However, since Cu or Ag exhibits adhesiveness, it is easy to cause open / close failure. In (a second element) improves the adhesiveness.
In other words, In present on the contact surface weakens the adhesiveness of Cu or Ag, and improves poor switching between contacts. In content
The reason specified in 1-30at% is that if In is less than 1at%,
The effect of In cannot be sufficiently obtained, and poor opening / closing occurs. In
If it exceeds 30 at%, the effect of stabilizing the contact resistance by Cu or Ag cannot be sufficiently obtained, and the contact resistance increases.
The contact resistance can be as high as 1Ω or more. Also, the variation of the contact resistance increases. A particularly desirable content of In is 10 to
It is 20at%.

According to a second aspect of the present invention, the first element is Cu and the second element is Zn in the first aspect of the invention. Is the same as

[0008]

The present invention will be described below in detail with reference to examples. (Example 1) The surface of a contact substrate made of a Fe-52at% Ni alloy having a length of 1 mm and a width of 1 mm was immersed in acetone and ultrasonically cleaned for 5 minutes.
Further, it was washed by electropolishing using phosphoric acid. Next, the substrate was set in a chamber of a vacuum evaporation apparatus, and the inside of the chamber was evacuated to 2 × 10 ⁻⁴ Pa or less. Then, the valve of the vacuum pump was half-opened to reduce the exhaust conductance. Ar gas was introduced until the inside of the chamber reached 1 × 10 ^-1 Pa. Next, a voltage of −400 V was applied to the substrate, a high frequency of 0.2 kW was generated from a high frequency antenna in the chamber, and ion bombardment treatment was performed with Ar ions to clean the surface of the substrate. Next, the substrate was heated and maintained at 100 ° C., and the metals shown in Table 1 were simultaneously evaporated from the respective electron beam evaporation sources on the surface of the substrate to form coating layers, thereby producing contacts. The alloy composition of the coating layer is Cu or Ag
The deposition rate of (first element) was fixed at 2 nm / sec, and various controls were performed by changing the deposition rate of In or Zn (second element). Here, the alloy composition of the coating layer was made uniform throughout. For comparison, the contents of In and Zn are as defined in claim 1.
Alternatively, a contact outside the scope of the invention described in 2 was also prepared.

Each of the obtained contacts is mounted on a pair of contacts in a glass container of a reed switch, N ₂ gas is sealed therein, and a driving magnetic field of 100 AT (Ampere Turn) is applied at room temperature. The switching operation was repeated between the contacts. The load conditions at this time are low load (5V-100 μA-100Hz) and high load (100V-
0.5A-10Hz). The number of operations until a failure occurred in the opening / closing operation was measured. The failure occurred when a failure occurred in opening and closing between the contacts or when the resistance between both poles of the reed switch became 1Ω or more. The results are shown in Tables 1 and 2.

[0010]

[Table 1] (Note) * The concentration of the first element is the balance of the concentration of the second element.

[0011]

[Table 2] (Note) * The concentration of the first element is the balance of the concentration of the second element.

As is clear from Tables 1 and 2, all the contact materials (Nos. 1 to 15) of the present invention have a long operating life under both high and low load conditions. In contrast, the contact material of the comparative example
(Nos. 16 to 21) had a small or large content of In or Zn, so that the operating life was short under both high and low load conditions.

As described above, a Cu-In alloy, A
Although the contact material coated with the g-In alloy or the Cu-Zn alloy has been described, the same effect can be obtained by using the alloy as a contact material as it is. Although the case where the coating layer is formed on the contact-size substrate has been described,
According to the present invention, the same effect can be obtained by forming a coating layer on a large-sized substrate and sizing the coating layer to the size of a contact.

[0014]

As described above, the encapsulated electrical contact material of the present invention comprises a Cu-In alloy, Ag-In alloy, or Cu-Zn alloy coated on a substrate.
In or Zn in the alloy suppresses adhesion between the contacts, and a long operating life is obtained. Also, since expensive Rh and Ru are not used, the cost is low. Therefore, there is an industrially significant effect.

Claims (2)

[Claims] An encapsulated electrical contact material wherein a coating layer having a thickness of 0.1 μm or more is formed on a contact substrate, said coating layer contains 1 to 30 at% of In, and the balance is made of Cu or Ag. . 2. An encapsulated electrical contact material wherein a coating layer having a thickness of 0.1 μm or more is formed on a contact base material, said coating layer contains 1 to 30 at% of Zn, and the balance is made of Cu.