JPS58744B2 - electrical contact materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrical contact material that is superior in anti-adhesion properties, contact resistance properties, and discharge and wear resistance properties as compared to conventional materials.

Electrical contact materials to which 1 to 10 at% of one or more of Si and Ge are added have already been patented in Japanese Patent Application No. 53-072171, but these electrical contact materials have insufficient discharge wear resistance. There was a drawback.

When a silver contact is used in a circuit that generates a discharge when closed, it exhibits an anode arc and is consumed in a deep and small area; however, when one or more of Si or Ge is added, as the amount of addition increases, the anodic arc is consumed in a shallow and large area. It shows a tendency to be consumed by area.

This tendency becomes conspicuous when the total concentration of Si and Ge added to m=species or higher is 101 t% or more, and if it is less than that, a considerably deep discharge exhaustion occurs.

However, the concentration of one or more of Si and Ge is 10at%.
If this is the case, there will be difficulties in processability using normal methods.

For this reason, internally oxidized contacts with a concentration of 10 at % or more have not been put into practical use.

In the present invention, the amount of one or more of Si and Ge added is 12 to 17a.
t%, and is characterized by internal oxidation after finely dispersing these additive elements in Ag, the purpose of which is to improve discharge wear resistance.

The most important properties of light-load contact materials for communications are:
Internally oxidized contacts containing up to 10 at% of Si or Ge are ideal because of their low and stable contact resistance and excellent adhesion resistance and discharge and wear resistance. It is a point of contact.

Conventionally, communication contacts have been made of expensive precious metals and alloys thereof, and are mounted on switches by cladding the base material, which is mainly made of Fe-based alloy, in the thinnest possible layer.

According to such a method, if the circuit network in which discharge occurs is subjected to many opening and closing operations, the depth of wear increases, the base material is easily exposed, and the contact resistance becomes unstable in many cases.

The present invention contains 12 to 17 or more of Si and Ge in Ag.
It is an object of the present invention to provide an electrical contact material which contains at% at%, undergoes internal oxidation treatment, maintains good contact characteristics, and has significantly improved wear characteristics.

In the above description, adhesive resistance characteristics, contact resistance characteristics, discharge resistance and wear resistance! Characteristics refer to the following:

The anti-adhesion property is expressed as the adhesion coefficient (separation force/contact force) in an ultra-high vacuum of 5×10 −10 Torr after cleaning the surface by bombarding the contact with argon ions.

Here, the contact force refers to the force required to bring the contacts into contact, and the separation force refers to the force required to separate the contacts that are in contact.

The contact resistance characteristics are expressed as the contact resistance after mounting the contact material on a wire spring relay and driving it 2 million times under no-load conditions in the atmosphere.

What are the discharge and wear resistance characteristics?Contacts mounted on wire spring relay1~, applied voltage 48V, RC discharge circuit (R-20Ω,
C = 0.22μF) when opening and discharging, and it is expressed as the depth of wear at the contact after 100,000 times of opening and closing.

Example I Six types of ingots shown in Table 1 of 20 mmφ x 300 mm were prepared at 1200°C with 1.2 to 17 at% of AgKSi added. Processed, hot rolled at approximately 600°C to form a 1 mm thick plate, and then cold rolled to a 150 mm thick plate.
It was made into a μm thin plate.

This was internally oxidized in the atmosphere at 800° C. for 11 hours, and then its discharge and wear resistance characteristics were measured.

The measurement results are shown in Table 1.

This shows that the material of the present invention containing 5i12 at% or more is more than twice as improved in discharge wear resistance as compared to the conventional material.

The anti-adhesive properties and contact resistance properties are shown in FIGS. 1 and 2.

The reason for limiting the Si concentration to 12 to 17 at% is 17a.
At a concentration exceeding t%, it is difficult to heat the silicon for 1 time even though it is L, and the primary silicon crystals during solidification become gigantic, making it difficult to make them fine and to disperse them uniformly. Depends on something.

Example 2 AgKGe was added at 0 to 17 at% and heated at 1100°C for 20
After making an ingot with a diameter of 300 mm and face-cutting it,
Processed at 300℃ with a hot groove roll into 4 squares, approximately 30mm
A plate material with a thickness of 2 mm was formed by hot rolling at 0°C, and then a thin plate material of 150 μm was formed by cold rolling.
After internal oxidation at 0° C. for 2 hours, discharge wear resistance was measured.

The measurement results are shown in Figure 3.

When the Ge concentration is 12 at% or more, the characteristics are significantly improved.

The contacts prepared by this method exhibited stable contact resistance characteristics of less than 50 mQ and good anti-adhesion characteristics with an adhesion coefficient of approximately 0.3.

Example 3 0 to 17 at% of Si and O to 17 at% of Ge were added to Ag, and 2011L1rLφ×3001L7 was heated at 1200°C.
After producing an IL ingot and flattening it, one end is processed into a conical shape with an apex angle of 60°, annealed at 700°C for 1 hour, and then hot extruded at 3000 atm and processed into a 4matφ wire. .

After further annealing at 600°C for 30 minutes, it was cold-annealed at 150°C.
Process it into a μm thin plate.

Thereafter, it was subjected to internal oxidation treatment in the same manner as in Example 1, and mounted on a wire spring relay, and the amount of discharge consumption was measured.

As a result, the discharge wear depth of the anode is as shown in Table 2.
Contacts in which the total concentration of Si and Ge exceeded 10 at % had a discharge wear depth of about 10 μm on the anode, showing good discharge resistance.

Note that the contact produced by this method exhibited stable contact resistance characteristics of 50 mΩ or less and good anti-adhesion characteristics with an adhesion coefficient of about 0.2.

The upper limit of the internal oxidation temperature is 840°C, the eutectic temperature of the Ag-Si alloy when AgKSi is added, and the upper limit of the internal oxidation temperature when AgKSi is added.
When adding , the eutectic temperature of Ag-Ge alloy is 651℃,
When AgKSi and Ge are added, the eutectic temperature of the Ag, -Si alloy is 840°C, and the appropriate lower limit is 250°C since internal oxidation takes a long time at low temperatures.

As explained above, by increasing the amount of Si and GeO in the internal oxidation contact containing one or more of Si and Ge to 12 to 17 at%, the wear depth is reduced to 10 μm even when used under conditions where discharge occurs during closing. It has the advantage that it is small in size and does not impair its anti-adhesive properties and contact resistance properties, making it more reliable as a communication contact.

Further, by increasing the amount of Si and GeO to 12 to 17 at%, cold processing becomes difficult, but hot processing is easy and does not cause any practical problems in production.

[Brief explanation of the drawing]

FIG. 1 shows the relationship between Si concentration and adhesive coefficient, FIG. 2 shows the relationship between Si concentration and contact resistance, and FIG. 3 shows the relationship between Ge concentration and discharge consumption of the anode.

Claims (1)

[Claims] One or more types of 1Si and Ge at a total solute concentration of 12 to 17at
An electrical contact material characterized by internally oxidizing a silver thread eutectic alloy containing %.