JPH07192565A - Contact material and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To provide a contact material which has an excellent conductivity, hardness, and cut-off property, by carrying out a specific treatment, after Cu or Ag is brought into contact with a sintered body which consists of Cr, W, Mo, Ti, Ta, Nb, Zr, Co, Ni, or a carbonate of one of the above elements. CONSTITUTION:The first component which consists of Cu and/or Ag is brought into contact with a sintered body which consists of the second component consisting of at least one sort of a single substance and/or a carbonate of Cr, W, Mo, Ti, Ta, Nb, Zr, Co, and Ni. Then, they are heated rapidly to a specific temperature at 400 deg.C or higher, and less than the melting point of the first component. Then, after maintaining the temperature at a specific value and for a specific time, the temperature is raised to the value of the melting point of the first component or higher. Then, the temperature is maintained at the melting point of the first component or higher until the first component is infiltrated into the sintered body which consists of the second component, and before or after such a time, the temperature is lowered gradually to the value lower 100 deg.C or more than the temperature of the first component, so as to obtain the required contact material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact material and a method for producing the same, and more particularly to a contact material having good conductivity and hardness, which is suitable for a vacuum contact material, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a contact material, a sintered body is first made of an arc-resistant component made of Cr or W alone or a carbide, and a highly conductive component made of Cu or Ag is brought into contact with the sintered body. In the state (hereinafter, referred to as a work), the high conductivity component is heated to a temperature equal to or higher than the melting point to infiltrate the arc resistant component, which is a sintered body, into a contact material, The so-called infiltration method is used.

Since the work contains a large amount of impurities such as adsorbed gas and water, it is necessary to remove these impurities. Conventionally, in order to remove these impurities, the temperature rising rate of the work is made as slow as possible. However, it has been considered effective to increase the temperature raising time.

On the other hand, when cooling the arc-resistant component after infiltrating the high-conductivity component, it has been said that it is better to cool slowly to room temperature so as to prevent nonuniformity during solidification.
However, when the work is put into the furnace and the temperature of the work is raised by heating, the heating rate is at most about 5 ° C./min. At this time, impurities such as adsorbed gas and moisture existing in the work are generated up to about 400 ° C and released to the outside of the work.
Since the temperature can be raised only at a heating rate of about in, components such as W and Cu are oxidized before being infiltrated, which causes problems in the infiltration process and also deteriorates the characteristics of the work. Was there. Oxygen and water in such a form are extremely difficult to remove from the work. The total amount of impurities remaining in such a work is 200 to 300.
It was as high as ppm.

Further, if the cooling rate of the work is increased, a non-uniform structure is formed when the highly conductive component is solidified.
Slow cooling to room temperature not only takes time to manufacture, but also during cooling, components such as W and Cu may be oxidized during cooling, which may cause deterioration of work characteristics. It was

[0006]

In view of the above-mentioned conventional problems, the present invention is such that the components such as W and Cu are hardly oxidized in the steps of temperature rising and cooling, and the conductivity and hardness are improved. It is an object of the present invention to provide a contact material suitable as an electric contact material for a vacuum valve or an air valve, and a method for manufacturing the same, because it is excellent and has excellent breaking characteristics.

[0007]

The contact material according to the first aspect of the present invention comprises a first component containing Cu and / or Ag.
0 to 90% by weight, balance Cr, W, Mo, Ti, Ta, N
b, Zr, Co, Ni as a simple substance and / or a second component consisting of at least one selected from the group consisting of carbides, and the total amount of impurities contained is 150 pp
It is characterized by being m or less.

Here, Cu and Ag are highly conductive components and contribute to the electrical conductivity of the contact material. Also, Cr,
W, Mo, Ti, Ta, Nb, Zr, Co, and Ni are arc-resistant components that contribute to the strength and wear of the contact material.

Here, the high conductivity components Cu and Ag are 10
If it is less than wt%, the conductivity of the contact is lowered, which is not preferable. On the other hand, if the amount exceeds 90% by weight, the wear resistance and welding resistance of the contacts are reduced, which is not preferable.
It should be noted that the components to be used have the optimum content according to the applied circuit.

Also, the arc-resistant components Cr, W, Mo, T
As i, Ta, Nb, Zr, Co, and Ni, simple substances or carbides are used. This is because it is a high melting point element and has good wear resistance. If the arc resistance component is less than 10% by weight, the strength of the contact is lowered, which is not preferable. Again 9
If the amount exceeds 0% by weight, the contact resistance becomes high, which is not preferable.

Here, the first component is preferably 30 to 80% by weight. Within this range, the contact has sufficient conductivity, wear resistance and welding resistance, and is particularly suitable as an electrical contact material for a vacuum valve.

The impurities contained are mainly oxygen, nitrogen and water. If the total amount of these exceeds 150 ppm, the withstand pressure is lowered particularly in a vacuum valve, which is not preferable. A preferable range is 10
It is 0 ppm or less.

The contact material of the second invention of the present application comprises 10 to 90% by weight of the first component composed of Cu and / or Ag.
The balance Cr, W, Mo, Ti, Ta, Nb, Zr, Co,
Consists of a second component of at least one selected from the group consisting of simple substance of Ni and / or carbide, and oxygen as an impurity of 100 ppm or less and hydrogen of 20 ppm
It is characterized by containing less than or equal to 30ppm of nitrogen.

Here, Cu, Ag and Cr, W, Mo,
Ti, Ta, Nb, Zr, Co and Ni are the same as the contact material of the first invention of the present application. The impurities contained are oxygen 100 ppm or less and hydrogen 20 p.
It is pm or less and nitrogen is 30 ppm or less. These gas components are generated from the contact material that has become high temperature when the contacts are opened and closed in the vacuum valve, which leads to the occurrence of the re-ignition phenomenon. If oxygen, hydrogen and nitrogen are below this value, respectively, this effect is small. If the oxygen content is 70 ppm or less, the hydrogen content is 10 ppm or less, and the nitrogen content is 20 ppm or less, the re-ignition phenomenon hardly occurs, which is more preferable.

The method of manufacturing a contact material according to the third aspect of the present invention is
The first component consisting of Cu and / or Ag is Cr,
W, Mo, Ti, Ta, Nb, Zr, Co, Ni simple substance and / or contact with a sintered body composed of a second component of at least one selected from the group consisting of carbides, and this is contacted with 400 A first step of rapidly heating to a predetermined temperature of not less than 0 ° C. and lower than the melting point of the first component, and holding at the predetermined temperature for a predetermined time, and then raising the temperature to the melting point of the first component or more. In the second step, the temperature above the melting point of the first component is maintained until the first component infiltrates into the sintered body composed of the second component, and then the melting point of the first component is exceeded. Also comprises a third step of gradually cooling to a temperature lower by 100 ° C. or more.

Here, Cu, Ag and Cr, W, Mo,
Ti, Ta, Nb, Zr, Co and Ni are the same as the contact materials of the first and second inventions of the present application. When a carbide is used as the second component, C
It is preferable to use o and / or Ni at the same time.

In order to bring the first component, which is a highly conductive component, into contact with the sintered body composed of the second component, which is an arc resistant component,
For example, there is a method in which the first component is made into a plate shape and the first component is made into a powder form.

In the first step, rapid heating to 400 ° C. or higher and a predetermined temperature below the melting point of the first component is
If the temperature is lower than 400 ° C., impurities such as adsorbed gas and water existing in the work are generated, and the temperature is slowly raised by heating in an environment where the impurities are present, and the conventional problems cannot be solved. Further, when the temperature is equal to or higher than the melting point of the first component, the first component melts before the second component, which is a sintered body, has a uniform temperature distribution. It is not preferred. The melting point of the first component, copper, is 1083.4 ° C., and the melting point of silver is 961.
It is 93 ° C. Further, the preferable predetermined temperature range is 5
It is 00-600 degreeC.

The reason why the temperature is kept at a predetermined temperature for a predetermined time is that the work has a uniform temperature distribution. Further, the reason why the temperature is raised to a temperature equal to or higher than the melting point of the first component is to melt the first component and infiltrate it into the sintered body of the second component. Here, a preferable range is a temperature 5 ° C. or higher above the melting point of the first component, and a particularly preferable range is a temperature 10 ° C. or higher above the melting point of the first component.
Further, the temperature rising rate at this time is preferably about 3 to 7 ° C./min.

The reason why the temperature above the melting point of the first component is maintained until the first component infiltrates into the sintered body composed of the second component is that the first component and the second component This is because the compound is sufficiently formed.

Further, after that, 100 is higher than the melting point of the first component.
The reason for gradually cooling to a temperature lower than ℃ is that the liquid phase is generated by the reaction of the first component and the second component even when cooled to the melting point of the first component. This is because it has a melting point lower than that of However, if the temperature is 100 ° C. lower than the melting point of the first component, these phases also solidify. Therefore, slow cooling to this temperature is sufficient because a substantially uniform arc-resistant component structure can be obtained. Further, the cooling rate at this time is preferably 3 ° C./min or less.

After cooling to this temperature, it is better to cool it faster in order to shorten the manufacturing time and to prevent the first component and the second component from being oxidized by impurities as much as possible. Even if it is gradually cooled as it is, the characteristics are not adversely affected as much as when the temperature is raised. Specifically, 5 ° C /
min or more is preferable, and one example is to take the work out of the furnace and allow it to cool.

The method for producing the contact material according to the fourth invention of the present application is carried out by placing the material in a furnace as rapid heating in the first step in the method for producing the contact material according to the third invention of the present application. It is a feature.

By thus introducing the work into the furnace heated from room temperature to the predetermined temperature, the work can be heated to the predetermined temperature in a minute time, and the impurities contained in the work can be increased. It is possible to reduce the risk that the first component or the second component is oxidized by the adsorbed gas or water. Therefore, the contents of impurities remaining in the contact material, particularly oxygen, hydrogen and nitrogen, can be dramatically reduced.

[0025]

With the above structure, a contact material having high conductivity and hardness and having a substantially uniform structure of arc-resistant component can be obtained. In addition, the amount of the gas component that causes the occurrence of the re-ignition phenomenon is effectively reduced.

[0026]

EXAMPLES Examples of the present invention will be described below. Example 1 A work piece was formed by placing a φ45 × 10 ^t mm Cr sintered body having a porosity adjusted to about 50% on a 50 × 50 × 6 mm Cu plate (Cu 55.4 wt%).

On the other hand, the vacuum furnace was set to 600 ° C., the above-mentioned work was put into this vacuum furnace, and the work was rapidly heated. The temperature of the furnace once dropped to 550 ° C, but immediately recovered to 600 ° C, and this temperature was maintained for 1 hour.

Thereafter, 110 at a temperature rising rate of 5 ° C./min.
The temperature was raised to 0 ° C. and kept for 0.5 hour to infiltrate Cu into the Cr sintered body. Then 900 at a cooling rate of 2 ° C / min
It was gradually cooled to ℃ and then radiated to room temperature.

FIG. 1 shows the relationship between the manufacturing time and the temperature of the work at this time. Example 2 A φ45 × 10 ^t mm sintered body of Cr having a porosity adjusted to about 50% was placed on a Cu plate of 50 × 50 × 6 mm to form a work (Cu55.4 wt%).

On the other hand, the vacuum furnace was set to 400 ° C., the above-mentioned work was put into this vacuum furnace, and the work was rapidly heated. The temperature of the furnace once dropped to 350 ° C, but immediately recovered to 400 ° C, and this temperature was maintained for 1 hour.

After that, 110 at a temperature rising rate of 5 ° C./min.
The temperature was raised to 0 ° C. and kept for 0.5 hour to infiltrate Cu into the Cr sintered body. Then 900 at a cooling rate of 2 ° C / min
It was gradually cooled to ℃ and then radiated to room temperature. Example 3 A φ45 × 10 ^t mm sintered body of Cr having a porosity adjusted to about 50% was placed on a Cu plate of 50 × 50 × 6 mm to form a work (Cu55.4 wt%).

On the other hand, the vacuum furnace was set to 900 ° C., the above-mentioned work was put into this vacuum furnace, and the work was rapidly heated. The temperature of the furnace once dropped to 800 ° C, but immediately recovered to 900 ° C, and this temperature was maintained for 1 hour.

After that, 110 at a temperature rising rate of 5 ° C./min.
The temperature was raised to 0 ° C. and kept for 0.5 hour to infiltrate Cu into the Cr sintered body. Then 900 at a cooling rate of 2 ° C / min
It was gradually cooled to ℃ and then radiated to room temperature. Example 4 A workpiece was formed by placing a W sintered body of φ50 × 5 ^t mm having a porosity adjusted to about 50% on a Cu plate of 50 × 50 × 5 mm (Cu 31.8 wt%).

On the other hand, the vacuum furnace was set to 600 ° C., the above-mentioned work was put into this vacuum furnace, and the work was rapidly heated. The temperature of the furnace once dropped to 500 ° C, but immediately recovered to 600 ° C, and this temperature was maintained for 1 hour.

Then, at a temperature rising rate of 5 ° C./min, 110
The temperature was raised to 0 ° C. and maintained for 0.5 hour to infiltrate Cu into the W sintered body. Then 900 ℃ at a cooling rate of 2 ℃ / min
It was slowly cooled to room temperature and then radiated to room temperature. Example 5 A workpiece was formed by placing a φ50 × 10 ^t mm W sintered body having a porosity adjusted to about 55% on a 50 × 50 × 3 mm Ag plate (Ag 40.0 wt%).

On the other hand, the vacuum furnace was set to 600 ° C., the above-mentioned work was put into this vacuum furnace, and the work was rapidly heated. The temperature of the furnace once dropped to 500 ° C, but immediately recovered to 600 ° C, and this temperature was maintained for 1 hour.

Then, the temperature is raised to 100 at a temperature rising rate of 5 ° C./min.
The temperature was raised to 0 ° C. and maintained for 0.5 hour to infiltrate Ag into the W sintered body. Then 800 ℃ at a cooling rate of 2 ℃ / min
It was slowly cooled to room temperature and then radiated to room temperature. Comparative Example 1 A workpiece was formed by placing a φ45 × 10 ^t mm Cr sintered body having a porosity adjusted to about 50% on a Cu plate of 50 × 50 × 6 mm (Cu 55.4 wt%).

This was placed in a vacuum furnace and heated at a temperature rising rate of 4 ° C./min. The furnace temperature was heated to 1000 ° C. and kept at this temperature for 1 hour. After that, 4 ℃ / min
The temperature was raised to 1100 ° C. at a heating rate of 1 and held for 0.5 hour to infiltrate Cu into the Cr sintered body.

Thereafter, it was cooled to room temperature at a cooling rate of 6 ° C./min. The relationship between the manufacturing time and the temperature of the work at this time is shown in FIG. Comparative Example 2 A work piece was formed by placing a φ50 × 5 ^t mm W sintered body having a porosity adjusted to about 50% on a 50 × 50 × 5 mm Cu plate (Cu 31.8 wt%).

This was placed in a vacuum furnace and heated at a heating rate of 5 ° C./min. The furnace temperature was heated to 1000 ° C. and kept at this temperature for 1 hour. After that, 5 ℃ / min
The temperature was raised to 1100 ° C. at a heating rate of 1 and held for 0.5 hour to infiltrate Cu into the W sintered body.

Then, it was cooled to room temperature at a cooling rate of 6 ° C./min. Comparative Example 3 A workpiece was formed by placing a φ50 × 5 ^t mm W sintered body having a porosity adjusted to about 50% on a 50 × 50 × 3 mm Ag plate (Ag 40.0 wt%).

This was placed in a vacuum furnace and heated at a temperature rising rate of 5 ° C./min. The furnace temperature was heated to 1000 ° C. and kept at this temperature for 1 hour. After that, 5 ℃ / min
The temperature was raised to 1100 ° C. at a heating rate of 1 and held for 0.5 hour to infiltrate the W sintered body with Ag.

Then, it was cooled to room temperature at a cooling rate of 6 ° C./min. Impurity content (ppm), conductivity (% IACS) of contact materials obtained by these manufacturing methods
And the hardness (HRB) was evaluated. The results are shown in Table 1.

[0044]

[Table 1]

From the results shown in Table 1, the contact material of the present invention has a content of impurities, especially oxygen, hydrogen, and nitrogen, which is 1/2 or less of that of the conventional material, and has high purity, high conductivity and high hardness. You can see that Example 6 WC containing 0.7% of Co of φ50 × 5 ^t mm with porosity adjusted to about 40% on an Ag plate of 50 × 50 × 4 mm
The sintered body was placed to form a work (Ag 31.0 wt
%).

On the other hand, the vacuum furnace was set to 600 ° C., the above-mentioned work was put into this vacuum furnace, and the work was rapidly heated. The temperature of the furnace once dropped to 500 ° C, but immediately recovered to 600 ° C, and this temperature was maintained for 1 hour.

Thereafter, the temperature is raised at a rate of 5 ° C./min to 100
The temperature was raised to 0 ° C. and maintained for 0.5 hour to infiltrate Ag into the WC sintered body. Then 800 at a cooling rate of 2 ° C / min
It was gradually cooled to ℃ and then radiated to room temperature. Comparative Example 4 WC containing 0.7% of φ50 × 5 ^t mm Co on a 50 × 50 × 5 mm Ag plate with porosity adjusted to about 40%.
The sintered body was placed to form a work (Ag 31.0 wt
%).

This was placed in a vacuum furnace and heated at a temperature rising rate of 5 ° C./min. The furnace temperature was heated to 800 ° C. and held at this temperature for 1 hour. After that, 5 ℃ / min
The temperature was raised up to 1000 ° C. and kept for 0.5 hour to infiltrate Ag into the WC sintered body.

Then, it was cooled to room temperature at a cooling rate of 6 ° C./min. Impurity content (ppm), conductivity (% IACS) of contact materials obtained by these manufacturing methods
And the hardness (HRC) was evaluated. The results are shown in Table 2.

[0050]

[Table 2]

From the results shown in Table 2, even when a carbide is used as the arc-resistant component, the contact material of the present invention has a content of impurities, particularly oxygen, hydrogen, and nitrogen, which is half that of the conventional one. The following shows that the purity is high, and the conductivity and hardness are high.

[0052]

As described above, according to the present invention, a contact material having high conductivity and hardness, and having a substantially uniform structure of arc-resistant component was obtained. In addition, contact materials were obtained that were unlikely to cause re-ignition. Therefore, by using this contact material as an electric contact material for vacuum valves, air valves, etc., high breaking characteristics are exhibited.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a manufacturing time and a temperature of a work in Example 1.

FIG. 2 is a diagram showing a relationship between a manufacturing time and a temperature of a work in Comparative Example 1.

Claims (4)

[Claims] 1. A first component comprising Cu and / or Ag in an amount of 10 to 90% by weight and the balance Cr, W, Mo, Ti,
The second component is composed of at least one selected from the group consisting of simple substances of Ta, Nb, Zr, Co, Ni and / or carbides, and the total amount of oxygen, hydrogen and nitrogen contained is 150 ppm or less. Contact material characterized by the following. 2. A first component comprising Cu and / or Ag in an amount of 10 to 90% by weight and the balance Cr, W, Mo, Ti,
Ta, Nb, Zr, Co, Ni simple substance and / or a second component consisting of at least one selected from the group consisting of carbides, and oxygen 100p as an impurity
A contact material containing pm or less, hydrogen 20 ppm or less and nitrogen 30 ppm or less. 3. A first component comprising Cu and / or Ag is added to Cr, W, Mo, Ti, Ta, Nb, Zr, C.
o, Ni is brought into contact with a sintered body composed of at least one second component selected from the group consisting of simple substances and / or carbides, and this is kept at 400 ° C. or higher and lower than the melting point of the first component. A first step of rapidly heating to a predetermined temperature; a second step of maintaining the temperature at the predetermined temperature for a predetermined time and then raising the temperature to a temperature equal to or higher than the melting point of the first component; A temperature equal to or higher than the melting point of the first component is maintained until it is infiltrated into the sintered body including the second component, and then gradually cooled to a temperature 100 ° C. or more lower than the melting point of the first component. And a step of manufacturing a contact material. 4. The method for producing a contact material according to claim 3, wherein the rapid heating in the first step is performed by charging in a furnace.