JPS62240728A - Production of contact point material - Google Patents

Abstract

PURPOSE:To stably obtain a contact point material having high electric conductivity and superior seizing by fusion resistance by a post-oxidation process by subjecting a hot rolled Ag alloy to annealing, cold rolling and annealing before internal oxidation. CONSTITUTION:A motor alloy ingot consisting of a metal for metallic oxide and Ag is formed, annealed, hot rolled and worked to the plate-shape. The resulting plate-shaped alloy is annealed, cold rolled, annealed again, blanked to the desired shape and internally oxidized to obtain a contact point material. The alloy annealed again may be internally oxidized without blanking and shaped to the desired shape. Since the contact point material has high electric conductivity, a rise in the temp. of a contact point made of the material can be inhibited even when large electric current flows, so the contact point hardly causes seizing by fusion.

Description

[Detailed Description of the Invention] [Technical Field] This invention relates to a method for producing an internally oxidized contact material.
The present invention relates to a method for manufacturing a so-called post-oxidation type contact material.

[Background technology]

Internal oxidation type contact materials in which metal oxides produced by internal oxidation are dispersed in an Ag matrix are used, for example, in contacts with a current capacity of about 1 to 30 A, such as in power relays.

One of the manufacturing methods for this contact material is usually called the post-oxidation type, in which an alloy ingot made of metal and Ag for metal oxide is obtained, hot rolled, and then internally oxidized. There is a way to do that. Although this contact material has the characteristic of being relatively resistant to welding, the electrical conductivity of the material itself is not quite sufficient, so welding at the contact may occur, especially when the contact current is large. The problem is that it becomes easier.

[Purpose of the invention]

In view of the above circumstances, it is an object of the present invention to provide a method for producing a contact material that can stably obtain a contact material that has high conductivity (good tetraconductivity) and excellent welding resistance.

[Disclosure of the invention]

In order to achieve the above object, the inventors investigated the relationship between the state of the structure within the contact material and the electrical conductivity from various angles. In contact materials that do not have good electrical conductivity, the crystal grains within the material are small and the metal oxides aggregate significantly at the grain boundaries, which acts as a barrier when electricity is applied and reduces the electrical conductivity. We then conducted a deeper study and found that in order to alleviate the agglomeration of metal oxides at grain boundaries, we should increase the grain size of the crystal grains and avoid stacking faults and dislocations inside the crystal grains. Because metal oxides tend to precipitate,
It was discovered that such a state could be created in the orientation i of the crystal grains, and in order to do so, hot-rolled alloy was
They discovered that it is sufficient to anneale the material once, then cold-roll it, anneal it again, and then perform internal oxidation treatment, and have completed this invention. Cold rolling and annealing contribute to increasing the grain size of crystal grains (recrystallization as coarse grains), and cold rolling also contributes to introducing dislocation inside the crystal grains.

Therefore, in this invention, after hot rolling the Ag alloy,
In a method for obtaining a contact material in which metal oxides are dispersed in an Ag matrix by internal oxidation treatment, the hot-rolled Ag alloy is once annealed, then cold-rolled, annealed again, and then The gist of this invention is a method for manufacturing a contact material that is characterized by performing internal oxidation treatment.

Hereinafter, an example of a method for manufacturing a contact material according to the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows the main steps in an example of the method for manufacturing a contact material according to the present invention in order. Second
The figure schematically shows the structure (crystal) state within the contact material obtained by this taxidermy method. FIG. 3 schematically shows the structure (crystal) state within the contact material obtained by the conventional manufacturing method.

First, an alloy ingot is created. In this example, A
g (silver), Sn (tin), In (indium), A
aAgA1 master alloy using f (aluminum) and Mn (manganese) (A1: l Q
wt% composition) and Ag-Mn master alloy (Ag: 90wt%
% of Mn:lQwt%), and using this,
Composition is sn: 9.3wt%, In: 5.1wt%, A1
An alloy of: 0°99wt%, Mn: 0.02wt%, and Ag: the balance was prepared by a master alloy method. The alloy is melted in an argon gas atmosphere using a high frequency furnace and formed (cast) into a 1 kg ingot using a mold.

Then, annealing is performed in an annealing (1) step. The annealing conditions were: argon gas (2 to 4 atm) at a temperature of 700°C;
It took about 45 hours. After annealing, 20
Let the ingot of dragon thickness be ln+ thick. In other words, it is processed into a plate shape.

This plate-shaped alloy is annealed again in the annealing (2) step.

The annealing conditions at this time were 700°C in an argon gas atmosphere.
for about 1 hour at a temperature of

After the annealing (2) step, it is then rolled in a cold rolling step.

After cold rolling, annealing is performed again in the annealing (3) step.

The annealing conditions at this time were 700°C in an argon gas atmosphere.
The temperature was 15 hours.

The alloy that has undergone the annealing (3) process is punched into a desired shape (not shown in the process diagram of FIG. 1) and subjected to internal oxidation treatment. Of course, it is also possible to perform internal oxidation treatment without punching, and then to shape it into the desired shape. The conditions for internal oxidation treatment are oxygen gas (approximately 4
Atmospheric pressure) at a temperature of 700° C. for about 65 hours.

Next, preferred processing conditions in each step will be explained. The cold rolling rate is preferably 3 to 30%. When it is less than 3%, as shown in Fig. 2, the grain size of the crystal grains 2 inside the contact material 1 does not become large (coarse), and as shown in Fig. 3, There is little difference in the particle size from the crystal grain 2'. At the same time, the effect of introducing dislocation is reduced, and the degree of agglomeration relaxation of metal oxide 4 at grain boundaries 3 is also little different from that at conventional grain boundaries 3'. It is more desirable that the rolling rate is 10 to 20%. This is because cold rolling in this range has the effect of precipitating and orienting metal oxide particles within the plate-shaped alloy perpendicularly to the contact surface 10, as shown in FIG. In this case, the conductivity and contact resistance characteristics are good, and the welding resistance is significantly improved. When the rolling ratio exceeds 30%, there is a tendency for cranking to occur easily during cold rolling.

The temperature in the annealing step should be at least the recrystallization temperature in an oxygen-free atmosphere and not exceed the melting point.
It is desirable that the temperature is about 00 to 700°C. Within this range, the effect of coarsening the crystal grain size is significant. The annealing time is usually selected from a range of 1 to 20 hours. Therefore, when the cold rolling rate is 10 to 20% and the temperature of the annealing process is in the range of about 400 to 700 °C,
A contact material having a large particle size and metal oxides oriented perpendicularly to the contact surface can be obtained. The obtained contact material was A g -S n O2-1n209-An
, 03-MnO composition.

Example 1 by changing the rolling rate in the above cold rolling process.
Four contact materials of ~4 were obtained. In Example 1, the rolling ratio was 5%.
In Example 2, the rolling ratio was 10%, in Example 3, the rolling ratio was 20%, and in Example 4, the rolling ratio was 30%.

For comparison, a contact material was obtained as Comparative Example 1 in exactly the same manner as in Example 3 except that the annealing (3) step was omitted.

Furthermore, as Comparative Example 2, annealing (2) in Example 1
A contact material was produced in exactly the same manner except that the process, cold rolling process, and annealing (3) process were omitted.

For Examples 1 to 4 and Comparative Example 1.2, electrical conductivity and crystal grain size (average grain size) were measured. The measured value of conductivity is IACS% (Cu conductivity is 100
%). Furthermore, using a metallurgical microscope or the like, the state of agglomeration of metal oxides and the state of orientation of metal oxides at grain boundaries between crystal grains were observed. The results are shown in Table 1.

In the above example, the metal element of the metal oxide dispersed in Ag is SnS I n% Aj! -and-Mn. Although the present invention is not limited to these metal elements, a contact material made of a combination of the metal elements described above has finer metal oxide particles, has high high temperature hardness, and has excellent durability in terms of material composition. The metal oxide is characterized by excellent weldability, and its composition range is Sn: 5 to 12 wt%, (n
:3-10wt%, Al:0.01-0.5wt%
, Mn: 0.01 to 0.5 wt%, Ag: remainder.

is preferable, and within this range, Sn: 5 to 12 wt%
, In: 3-10wt%, Ant: 0.02-0.2w
t%, Mn: 0.02 to 0.2 wt%, and Ag: the balance is more preferable because the finer refinement effect is ensured.

The reason why it is preferable that the composition range is as above is as follows.
It is as follows. If Sn is below 5wt% or In
If it is less than 3 wt%, welding resistance and abrasion resistance tend to be insufficient. When Sn exceeds 12 wt% or In exceeds IQwt%, workability and internal oxidation treatment tend to be insufficient. Al
When Q and Mn are less than 0.01 wt%, it becomes difficult to obtain the effect of making the metal oxide finer, and when Q and Mn are more than 5 wt%, conductivity and workability tend to decrease.

As shown in Table 1, the contact materials of Examples 1 to 4 have better electrical conductivity than the contact materials of Comparative Examples 1 and 2. This is also supported by the observation results of agglomeration of oriented perpendicular to the plane.

〔Effect of the invention〕

As described in detail above, in the method for obtaining a contact material in which metal oxides are dispersed in an Ag base by hot rolling an Ag alloy according to the present invention and then subjecting it to internal oxidation treatment, the hot rolled Ag The alloy is once annealed, then cold rolled, annealed again, and then subjected to the internal oxidation treatment. As a result, the electrical conductivity of the resulting contact material improves, so that in contacts using this material, temperature rise can be suppressed even when the current is large, making it difficult for welding to occur at the contacts.

[Brief explanation of drawings]

FIG. 1 is a step-by-step process explanatory diagram showing the main steps in an example of the method for manufacturing a contact material according to the present invention, and FIG.
The figure is an explanatory diagram schematically showing the structure of the contact material obtained by this taxidermy method, and Figure 3 is a schematic illustration of the structure of the contact material obtained by the conventional manufacturing method. The explanatory diagram, FIG. 4, is an explanatory diagram showing a state in which the metal oxide is oriented perpendicularly to the contact surface. 1... Contact material 2... Crystal particles 3...
Grain boundary agent Patent attorney Takehiko Matsumoto Figure 1 Figure 2 Procedural amendment (Spontaneous July 5, 1985, Showa 61 No. 084736 No. 3, Relationship with the person making the amendment Myoku Patent application colonel) Address: 1048 Kadoma, Kadoma City, Osaka Prefecture
Name (583) Matsushita Electric Works Co., Ltd. Representative (Facing St. Sadao Fujii 4, Agent 6/Subject of amendment Patent application 1984-08473
No. 6, Specification 7, Contents of the amendment ■ In the top right column of Table 1 on page 11 of the specification, the words "Characteristics of contact material" are corrected to "Characteristics of contact material."

Claims (4)

[Claims] (1) In a method for obtaining a contact material in which metal oxides are dispersed in an Ag matrix by hot rolling an Ag alloy and then subjecting it to internal oxidation treatment, the hot rolled Ag alloy is once annealed, and then A method for producing a contact material, characterized in that the internal oxidation treatment is performed after cold rolling and reannealing. (2) The method for producing a contact material according to claim 1, wherein the cold rolling rate is 3 to 30%. (3) The method for manufacturing a contact material according to claim 1, wherein the temperature during annealing is 400 to 700°C and the annealing time is 1 to 20 hours. (4) The method for producing a contact material according to any one of claims 1 to 3, wherein the metal element of the metal oxide is Sn, In, Al, and Mn.