JPS6013039A - Contact material - Google Patents

Abstract

PURPOSE:To obtain a contact material for large-current high-frequency switching with superior arc resistance, wear resistance and contact characteristics by dispersing a specified amount of Al2O3 in a Cu matrix. CONSTITUTION:This contact material is obtd. by dispersing 0.1-5wt% Al2O3 in a Cu matrix. By dispersing very hard Al2O3 in the hard Cu matrix, a dispersion strengthening effect is produced, and the hardness of the whole contact material is increased to improve the wear resistance. At the same time, the heat resistance is improved to provide superior arc resistance. Since the contact material is hard, the contact pressure can be increased. Since the matrix is made of Cu, the contact resistance is not especially high, and superior contact characteristics are provided. Cu-Al alloy powder is mixed with Cu2O powder, and after internally oxidizing the Al by heating, the mixture is compacted and sintered to manufacture said contact material. A mixture of Cu powder with Al2O3 powder may be compacted and sintered.

Description

Detailed Description of the Invention The present invention relates to materials for electrical contacts that frequently open and close large currents, such as contacts for relays, cam switches, cabanas, etc. that control the inductive load of high-output DC motors. By using an alumina dispersion-strengthened copper alloy in which AA'203 (alumina) is dispersed, arc resistance, wear resistance, and contact characteristics are improved to withstand high current switching. This is what I did.

Conventional materials for this type of high-current, high-frequency switching contacts include:
Alloy contact materials such as Pt-Ir alloy or Ag-Cu alloy are known. Although these alloy-based contact materials have relatively low contact resistance and are stable in the initial stage of use, Ag-'Cu alloys in particular are susceptible to welding in a short period of time due to spark discharge, resulting in poor arc resistance. On the other hand, Pt-Ir alloy has the disadvantage that the contact resistance increases rapidly unless the contact resistance is increased, and this type of alloy contact material generally has the disadvantage of high specific resistance. There is. Carbon-based contact materials are also sometimes used for the contacts mentioned above, but carbon-based contact materials have a higher specific resistance than alloy-based contact materials, and therefore resistive heat generation occurs at large currents of about 5 to IOA. The disadvantage is that the contact becomes large and softens the spring material to which the contact is attached.

On the other hand, recently, as described in Japanese Patent Application Laid-Open No. 58-16043, oxide-dispersed silver alloys in which various metal oxides are dispersed in an Ag base have been used for high-current, high-frequency switching contacts as described above. It is now used as a material.

This type of contact material has an electrical resistance close to the specific resistance of Ag itself, and has a much lower electrical resistance than the aforementioned alloy contact material. However, since it is made of Ag as a matrix, it is soft and therefore has low wear resistance, and also has drawbacks such as being unable to increase contact pressure.

This invention was made in view of the above circumstances, and is a contact suitable for high-current, high-frequency switching, which has excellent arc resistance, wear resistance, and contact characteristics, and whose service life can be significantly extended compared to conventional ones. The purpose is to provide materials.

That is, the contact material of this invention has a Cu (copper) base with 01
~5% of A-i2O5 (alumina) is dispersed, and by using Cu as the base and Al2O3 as the dispersed phase, good arc resistance, wear resistance, and contact characteristics can be achieved. It was.

The contact material of the present invention will be explained in more detail below.

In the contact material of the present invention, the base is Cu, which is harder than Ag, and A7. ．． Coupled with the dispersion strengthening effect of 03, the overall hardness is high and excellent wear resistance is obtained. Further, the dispersion of Al2O3 improves the υ heat resistance and provides excellent arc resistance.

In terms of contact characteristics, as mentioned above, it is hard, so it is possible to increase the contact pressure, and since the base is Cu, the contact resistance is not particularly high, and the electrical resistance is also pure Cu.
Close to O value. However, if A1206 is less than 0.1 inch, Al
The effect of improving arc resistance and wear resistance due to the dispersion of 2O3 is hardly obtained, and on the other hand, if Al2O3 exceeds 5 cm, the conductivity becomes low and it becomes unsuitable as a contact material.

Therefore AJ? The amount of 203 was limited to a range of 0.01 to 5%.

Methods for manufacturing the contact material of this invention include the so-called internal oxidation method and the alumina powder mixed sintering method.
The internal oxidation method is suitable when the amount of 2O3 is a relatively small amount with a diversity of 0.01 to 2.0.
If the amount is relatively large, from about 100 cm to 5000 cm, the alumina powder mixing and sintering method is suitable.

To explain the former internal oxidation method, in this case, first, a Cu--A1 alloy powder of about 1,100 methane containing about 0.05 to 1.0% of A7 is produced. That C
As a means for producing the u-A1 alloy powder, for example, N
A gas atomization method using an inert gas such as 2 gases may be applied. Next, an oxidizer that supplies oxygen for oxidizing A7 in the alloy powder to A12o6 is added to and mixed with the Cu-AA alloy powder. This oxidant is
In the case of the contact material of this invention, C with an average particle size of about 1 to 2 μm
It is desirable to use u20 (cuprous oxide). In this case, the amount of Cu 20 added may be an amount sufficient to supply 0 necessary to oxidize Al in the Cu-A1 alloy powder, for example, the amount of Al in the Cu-AA gold alloy is Af).
Then, the Cu 20- required for the Cu-A7 alloy powder 1001 is given by B (P). Such an oxidant, for example, Cu 20 powder, can be used as Cu-AA! After adding and blending the A7 alloy powder, the mixture is sufficiently stirred and mixed using a ball mill or a V-type mixer. Then, the mixed powder is subjected to internal oxidation treatment. That is, for example, the mixed powder is filled in a copper container,
It is preferably heated at a temperature of 800 to 950°C for 1 to 10 hours. By heating in this way, Cu −
Al in the A7 alloy powder is oxidized by 0 in Cu2O, producing fine Al2O5 and Cu2
0 is returned.

Note that the reason why the mixed powder is filled in the copper container is to prevent the mixed powder from being contaminated during the internal oxidation treatment. After performing the internal oxidation treatment in this way, in order to mainly reduce the oxides on the powder surface, especially the unreduced Cu 20, and improve the sinterability, a reducing atmosphere such as a hydrogen atmosphere is added. At 800-b. Al2O3-containing Cu obtained in this way
If the powder is compacted and sintered, the desired material, namely C
A material in which Al2O3 is dispersed in the u base can be obtained. Various known methods can be used as specific means for compacting and sintering the powder.
It is sufficient to perform hot embossing at a temperature of 750 to 900°C, further cold rolling if necessary, and annealing at a temperature of about 750 to 900°C.

On the other hand, in the case of the latter alumina powder mixing and sintering method, Cu powder and Al2O5 powder having a particle size of approximately 0.01 to 1 μm may be mixed, and the powder may be compacted and sintered according to a conventional method. For example, the mixed powder is filled into a copper can or pipe, hot extruded at 800 to 900°C at an extrusion ratio of 8 to 30 in the same manner as described above, and further cold rolled if necessary. Annealing may be performed at about ~900°C.

Examples and comparative examples of this invention are described below.

Examples 1 to 5 Various amounts of Al were added to the Cu base as the material for a pair of contact pairs.
Using a material in which 2O was dispersed, the service life of the contact pair was examined using a life test device as shown in FIG. In FIG. 1, 1 and 2 are a contact pair, 3 is a cam for opening and closing the contact pair 1 and 2, 4 is a permanent magnet field type DC motor as a load, and 5 is a DC power source. In addition, the life test conditions were: DC power supply voltage 12v1 current 4A, contact pressure when closed 601
The opening/closing cycle was set to close for 2 seconds and open for 5 seconds. The results of this life test are also shown in Table 1. Note that here Al2
Materials with an O3 content of 20% or less were manufactured by the internal oxidation method as described above, and materials with an O3 content of more than 2.0% were manufactured by an alumina powder mixing sintering method.

Examples 6 to 8 Among a pair of contacts, a material in which various amounts of Al2O3 were dispersed in a Cu base was used as the material for one contact, and a 70%Pt-30%rr alloy was used as the material for the other contact. The same life test as above was conducted using the same. The results are also shown in Table 1.

Comparative Example 1 70% Ag -30% as material for a pair of contacts
A life test similar to the above was conducted using a Cu alloy.

The results are also shown in Table 1.

Comparative Example 2 A 15% CdO dispersion-strengthened silver alloy in which 15% CdO was dispersed in an Ag base was used as the material for a pair of contacts.
A life test similar to that described above was conducted. The results are also shown in Table 1.

Table 1 As is clear from Table 1, Comparative Example 1, which used an Ag-Cu alloy material as the contact material, reached the ship in an extremely short period of time and became difficult to use. In the case of each example in which alumina dispersion-strengthened copper alloy was used for both, the service life was extremely long, and it was possible to open and close at least 200,000 times.

Furthermore, it is clear that the service life is long when compared with Comparative Example 2 using an Ag-based dispersion-strengthened alloy.

As is clear from the above explanation, the contact material of the present invention has superior arc resistance and wear resistance compared to conventional alloy-based contact materials, and has superior electrical resistance and contact resistance like conventional carbon-based contact materials. It is not particularly large, and has high wear resistance compared to conventional oxide-dispersed silver alloys, and can increase contact pressure. Therefore, it has various advantages, such as being able to significantly extend its service life compared to conventional methods, and being suitable for high-current, high-frequency switching.

[Brief explanation of the drawing]

Figure 1 is a schematic illustration of a life test device applied to the contact material of the example.

Claims (1)

[Claims] 0.1 to 5 inches (weight%, same below) of Al in Cu base
Contact material in which 2O3 is dispersed.