JPH04154017A - Manufacture of copper/chrome electrode material - Google Patents

Abstract

PURPOSE:To obtain a homogeneous Cu-Cr electrode material without cavity by determining grain diameter and grain size distribution of Cu powder, and filling the powder, naturally, and carrying out sintering, and infiltrating the Cu powder. CONSTITUTION:After a mixed powder 1 of Cu powder having grains of 50mum and less in diameter by 60% or more, and Cr powder is filled in a container 2, it is heated at a temperature not lower than the melting point of Cu in an inactive atmosphere, and a Cu-Cr ingot 1a is obtained thereby. Copper 3 for infiltration is then set on the Cu-Cr ingot 1a, and it is heated, and the copper 3 for infiltration is infiltrated in the void in the Cu-Cr ingot 1a. The copper is deposited airtight in the mixed powder 1 of Cu powder and Cr powder, while the copper 3 for infiltration is not oozed around, and an electrode material of homogeneous composition without cavity can thus be obtained.

Description

[Detailed description of the invention] Human industrial application field The present invention relates to a method of manufacturing a copper-chromium electrode material.

SUMMARY OF THE INVENTION The present invention provides l! (hereinafter referred to as Cu) and chromium (hereinafter referred to as Cu)
In manufacturing an electrode material consisting of Cr (expressed as
The mixed powder is naturally filled into a container and heated at a temperature higher than the melting point of Cu in an inert atmosphere to form Cu-
After obtaining a Cr ingot, a Cu-Cr electrode material is obtained by infiltrating Cu into the voids of the Cu-Cr ingot, or by placing Cu on a mixed powder and performing Cu infiltration along with sintering. .

2. Description of the Related Art One of the important properties required of electrode materials for vacuum interrupters is high current interrupting performance.

In recent years, as an electrode material with good current interrupting performance, Cr is used as a high melting point material and Cu is used as a conductive material.
-Cr electrode materials have been developed.

Conventionally, this Cu--Cr electrode material has been manufactured by an infiltration method or a sintering method.

In the infiltration method, Cr powder is heated and degassed at a temperature above 1000°C in a vacuum or an inert atmosphere such as hydrogen to obtain a Cr skeleton, and Cu is placed on this skeleton. In this method, Cu is heated at a temperature higher than the melting point of Cu to dissolve Cu into the voids of the Cr skeleton to obtain a Cu-Cr alloy.

In addition, in the sintering method, a mixed powder obtained by mixing Cr powder and Cu powder in a desired ratio is mixed at 981 to 6867 MPm (100
0 to 7000 kgf/ej), and then heated in a vacuum or in an inert atmosphere such as hydrogen at a temperature below the melting point of Cu to fuse the powders together. This is the method that the invention seeks to solve! ! However, the porosity of the skeleton is determined by the physical properties of the Cu powder, such as the particle size, bulk density, and particle size distribution of the Cu powder. Electrode materials with a Cr ratio are particularly advantageous (i) When infiltrating Cr into a Cr skeleton, if the Cr surface is oxidized, the infiltration will be insufficient and cavities may occur on the electrode surface or inside. There are problems such as.

In addition, the sintering method has problems such as: ■ Requires advanced technology during manufacturing; ■ Depending on the manufacturing conditions, cavities may remain inside the electrode; ■ Requires expensive equipment such as a press molding machine. There is a point.

Means for solving MM In view of the above circumstances, a mixed powder of Cu powder and Cr powder -
tIJ! We tried to infiltrate this with Cu, or to infiltrate it with Cu, by filling it into a container under its own weight and sintering it to form a skeleton. At this time, in order to examine the influence of the particle size of the Cu powder, electrode materials were produced by changing the particle size of the Cu powder, and the production process and the produced electrode materials were observed.

As a starting material, the following Cu powder was mixed with a Cr powder whose particle size was 80% distributed between 100 and 60 μm, and the dependence of the Cu particle size was investigated.

The above powders were weighed and mixed sufficiently so that Cr was 25% by weight and Cu was 75% by weight, and 250g of this mixed powder was filled into an alumina container with an inner diameter of 80m.
Heated to 1130° C. for 1 hour in a vacuum of orr.

During heating, the mixed powder (shrinks significantly) due to the melting of Cu. The outer diameter of the obtained skeleton was as shown in the table below.

Next, place enough Cu lumps on the skeleton to fill the voids (a sintered body with the same particle size and distribution ratio as Arashi 3,
35 m in diameter, 8 thicknesses, and 70 g in weight), and 10-
The skeleton was heated to 1130° C. for 1 hour in a vacuum of Torr to infiltrate Cu into the skeleton.

&1. In the ingot (electrode material) using Na2 Cu powder, Cu protruded around the skeleton. When we cut the ingot and examined the inside, we found that there were nests inside the ingot.In the ingot using C11 powder of &3, there was no excess Cu protruding into the surrounding area, and no nests were found inside. There wasn't.

The above result is k'3. Like the Cu powder of jMl 2, the particle size of the Cu powder is large b) and the shrinkage when obtaining the skeleton is small, so when Cu is infiltrated in the infiltration process, the C
This is because u penetrates the void in the skeleton and seeps out into the surrounding area.

When we conducted similar trial production and investigation for N113 Cu powder with different particle size distributions, we found that the particle size distribution was 60%.
If the amount decreases, Cu powder with a large particle size increases, causing cavities in the ingot and causing the copper for infiltration to ooze out.

Note that almost the same results were obtained not only when Cu was infiltrated after producing the skeleton as described above (also when infiltration was performed simultaneously with sintering of the mixed powder).

From the above, it can be seen that the method for producing a Cu-Cr electrode material according to the first invention uses Cu having a particle size of 60% or more under 50 μm.
After filling a container with a mixed powder of Cu powder and Cr powder, it is heated at a temperature higher than the melting point of Cu in an inert atmosphere to convert it to Cr powder.
The method is characterized in that a u-Cr ingot is obtained, copper for infiltration is placed on top of the Cu-Cr ingot, and heated to infiltrate the copper for infiltration into the voids of the Cu-Cr ingot.

Further, the method for producing a Cu-Cr electrode material according to the second invention is a method for producing a Cu-Cr electrode material having a particle size of 60% or less of 50 μm or less.
This method is characterized by filling a container with a mixed powder of powder and Cr powder, placing IW immersion copper on top of the mixed powder, and heating it at a temperature equal to or higher than the melting point of Cu in an inert atmosphere.

Function: In the above method, since the mixed powder of Cu powder and Cr powder is closely welded, the copper for infiltration does not seep into the surroundings, and an electrode material with a dense composition without voids can be obtained.

26 Example vacuum interrupter is an example of its schematic structure: e! ! As shown in FIG. 5, electrodes 13 and 14 are integrally provided on the opposing surfaces of a pair of lead storages 11 and 12 that are in a -is shape with each other. These electric currents [13,1
A central portion of the outer periphery of a cylindrical shield 15 surrounding the shield 15 is held between a pair of insulating cylinders 16 and 17 surrounding the shield 15.

One of the lead rods 11ζ is integrally fixed to the metal end plate 18 joined to one end of the insulating tube 16 while being passed through the metal end plate 18 in a secure manner. The other lead l112, which is connected to a mold movement device (not shown), is connected to the other metal end plate 1 which is securely joined to the other end of the other insulating cylinder 17.
9 via the Befouz 20, and as the drive device operates, the movable electrode 14 can open and close the fixed electrode 13 in a direction opposite to the electrodes 13 and 14. ing.

The above electricity! The electrode material for forming 113 and 14 is manufactured as follows.

First, Cr powder with a particle size of 80% to 60 μm and Cu powder with a particle size of 80% below 50 μm are mixed in weighed amounts so that the weight of Cr and the weight of Cu are 75%, respectively. As shown in FIG.
Fill with 0g.

Next, the container 2 is placed in a vacuum furnace and heated to 10-'Tor.
11 while degassing in a vacuum of r or in an inert gas.
Heat and hold at 30°C for 1 hour. During heating, Cu melts, so the skeleton 1a becomes greatly shrunken as shown in FIG. 1 (bl).

Place #i43 for infiltration 1 m above this skeleton as shown in FIG. 1(0). The infiltration l1lI3 is a round rod (or disk) with a diameter less than 80% of the diameter of the skeleton 1a, and the amount thereof is sufficient to fill the voids in the skeleton 1a.

Here, C with a particle size of 50 μm or less is distributed at 80%.
A sintered body of U powder with a diameter of 35 mm, a thickness of 81 mm, and a weight of 70 g was used.

With the infiltration 113 placed on the skeleton la, 10
The sample was placed in a vacuum of -' Torr and heated and maintained at 1130° C. for 1 hour in an inert gas to infiltrate Cu into the voids of the skeleton 1a. Cu in the surrounding area: A tight electrode material was obtained that did not seep out and had no cavities inside. For example, a density ratio of 98% can be obtained4.The lower limit of the infiltration temperature is set to be equal to or higher than the melting point of Cu, and the upper limit is set to the melting point of Cu.
The melting point of +60°C.

This is because if the infiltration temperature is too high, cavities may occur due to seepage of Cu.

As mentioned above, the Cu powder contains 60% or more of particles with a particle size of 50 μm or less. 41 above.
If the particle size is larger than that or if the particle size distribution is less than 60%, as in the case of Na2, as shown in Figure 2, the voids 4 in the skeleton 1& will become larger, and when Cu is immersed, the voids will disappear. A problem arises in that Cu seeps out through 4. In the figure, the diameter of the infiltrated copper 3 should be placed on the skeleton 1a.The diameter of the infiltrated copper 3 should be less than 80% of the diameter of the skeleton 1a (for example, the diameter should be 580% or more). As shown in FIG. 3, the W43 for infiltration protrudes from the outer edge of the skeleton 1a and does not penetrate into the rear part of the skeleton.

In addition, the component ratio of Cu in the electrode material is 80 to 40
Weight%. If Cu is 80% by weight, Cu may ooze out during the production of skeleton 1a, leaving cavities inside after infiltration, and if Cu is < OIi amount % or less than
This is because the performance as an electrode cannot be maintained.

The component ratio of Cr is 60 to 20% by weight.

The electrode material obtained as described above is machined,
The electrodes are referred to as 13 and 14.

Method 1 of the above example, after the skeleton, which is a sintered body, is produced! Although S immersion is performed, sintering and infiltration may be performed simultaneously. The example method is shown in FIG.
Cr powder with 80% of ~60 μm and particle size 5
A Cu powder in which 80% of particles having a diameter of 0 μm or less is present is used, and the respective powders are weighed and thoroughly mixed so that the Cr content is 25% by weight and the Cu powder is 75% by weight.

As shown in Fig. 4 (al), this mixed powder 1 has an inner diameter of 8G-
250g of alumina is filled horizontally into the alumina volume iIz using its own weight.

Place infiltration powder @3 on top of shoulder powder 1. For infiltration @3, a sintered body of Cu powder in which 80% of the particles had a particle size of 50 μm or less was used, which had a diameter of 35 layers, a thickness of 8 layers, and a weight of 70 g.

The infiltration wI3 was placed on the cloudy powder 1 and these were set in a vacuum furnace, and heated and held at 1130°C for 1 hour in a vacuum of 10 Torr or in an inert gas.Mixed powder 1
At the same time, Cu and Cr are fused together, and the immersed copper 3'a is melted and penetrates into the Cu-Cr void. The state after sintering and infiltration is shown in Atsushi 4 Figure 1b), 3b is the obtained implant) 1
This is the residual Cu of b.

As described above, in the method of the present invention, after obtaining the skeleton, C
The method of infiltrating Cu is a method of performing sintering and infiltration in one step, but when manufacturing a large electrode with an electrode diameter of 70 mm or more, it is necessary to infiltrate Cu after obtaining the skeleton. is more suitable. This is because when infiltration copper is placed on powder, cavities may form.

Effects of the Invention According to the method for manufacturing a Cu-Cr electrode material according to the present invention, the particle size and particle size distribution of the Cu powder are defined, and after being filled all at once, Cu is infiltrated or sintered and infiltrated. As a result, a uniform and void-free @rich Cu-Cr electrode material can be obtained.

Further, according to the method of the present invention, the electrode material obtained is Cu-
There is a wide range of Cr composition options, making it possible to obtain an electrode material with any Cu/Cr ratio.

Furthermore, compared to conventional sintering methods, no high-pressure process is required, so the manufacturing process is easy to manage, and manufacturing equipment can be simplified and costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the Cu-Cr electrode material manufacturing process according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of how copper for infiltration seeps out, and Fig. 3 is an illustration of how copper for infiltration overflows. An explanatory diagram of the flow,
Figure 4 is an explanatory diagram of another example method, and Figure 5 is a sectional view of an example of a vacuum interrupter. In the drawings, 1 is a mixed powder, 1a is a skeleton, 1b is an ingot, 2 is an alumina container, 3 is copper for infiltration, 13.141 is electrode. Patent application agent Akira Co., Ltd.

Claims (2)

[Claims] (1) After filling a container with a mixed powder of copper powder and chromium powder with a particle size of 60% or less of 50 μm or less, the mixture is heated at a temperature above the melting point of copper in an inert atmosphere to form a copper-chromium ingot. A method for producing a copper-chromium electrode material, characterized in that copper for infiltration is placed on the copper-chromium ingot and heated to infiltrate the copper for infiltration into the voids of the copper-chromium ingot. (2) Fill a container with a mixed powder of copper powder and chromium powder with a particle size of 60% or less of 50 μm or less, place copper for infiltration on top of the mixed powder, and place the copper powder on top of it. A method for producing a copper-chromium electrode material, characterized by heating at a certain temperature.