JPS6316849B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vacuum shield breaker electrode, and more particularly to an improved vacuum shield breaker electrode for low surge use and a method for manufacturing the same. Conventionally, Cu or Cu-Co alloy with Bi,
Added a large amount of low melting point/high vapor pressure elements such as Pb, Te or Se, and manufactured by powder metallurgy.
Ag-Wc or Ag-Wc-Co materials are known. The former Cu alloy-based electrode is
In the initial state before the short-circuit current dies out, it exhibits low surge characteristics, but after the short-circuit current dies down, low-melting-point, high-vapor-pressure elements such as Bi and Pb seep out and evaporate, resulting in a decline in surge characteristics. It is not practical because it tends to have a tendency and is unreliable. On the other hand, the latter Ag-based material exhibits good low surge properties both before and after rupture, but its rupture performance is not very good, so there is a limit to increasing capacity, and the material is brittle, so machinability is poor. There is a manufacturing problem such as not being good. The present inventors conducted research to overcome the defects of the conventional products and proposed a new and improved low-surge type electrode (Japanese Patent Application No. 81425/1982). The proposed Co--Ag--Te or Se-based electrode not only has excellent low surge properties before and after shearing, but also has high large current shearing performance. However, Co-
Since Ag-based molten metal is of a two-liquid phase separation type, it cannot be manufactured by ordinary melting, so it is manufactured by means such as sintering and impregnation. is Co sintered body with Ag,
A method of impregnating Te, Se, etc. had to be adopted. However, the formability of Co powder is not so good, and disadvantages include extremely poor workability, such as ridge edges and corners being chipped, and inconvenient phenomena such as cracking occurring during sintering of the compact. There is. In addition, the base metal is pure Co.
If this method is used, the cost of raw materials will be too high, and it will be extremely disadvantageous industrially. The present inventors have conducted further research in order to eliminate such drawbacks, and have developed an improved electrode that has performance equivalent to or better than the Co-Ag-Te and Se-based electrodes described above, and that can be manufactured easily and at low cost. We have discovered an electrode and its manufacturing method. That is, an object of the present invention is to provide an electrode for a vacuum shield breaker having improved low surge properties and high surge resistance. Another object of the present invention is to provide a new method for manufacturing a vacuum shield or disconnection electrode that is easy to manufacture and inexpensive. Other objects and excellent effects of the present invention will become clearer from the following description. The present inventors have developed Fe
- As a result of research into electrodes based on the combination of Co and Co, we have arrived at the present invention. According to the invention, powdered Fe and Co mixture or
In the sintered compact of Fe-Co alloy powder, Ag-Te,
After forming a vacuum shield electrode impregnated with Ag-Se or Ag-Te-Se alloy and a powdered Fe and Co mixture or Fe-Co alloy powder dissolved in a non-oxidizing atmosphere, The molded body is fired in a non-oxidizing atmosphere, and a molten metal of Ag-Te, Ag-Se or Ag-Te-Se alloy, which has been previously melted in a non-oxidizing atmosphere, is infiltrated into the fired molded body. A manufacturing method is provided. In the present invention, the fired compact is produced by molding and firing a powder mixture of Fe and Co or Fe--Co alloy powder. However, it is more preferable for the electrode according to the present invention to have a skeleton made of a fired compact of an alloy. The skeleton composed of Fe and Co is
A material containing 25 to 75% by weight of Co is used. If the amount exceeds this range, the object of the present invention will not be achieved, which is disadvantageous. In the case of Fe-Co alloys, although the reason is unknown, the electrical resistivity value decreases in the range of about 26 to 76% by weight of Co, and in such materials, the Fe and Co It is thought that a regular lattice is formed and the regularity of atoms at the points of the sintered crystal lattice improves, resulting in less scattering of free electrons that govern electrical conduction, resulting in a lower specific resistance. In particular, a composition with a Co content of 50 to 76% by weight has a resistivity value lower than that of pure Fe or pure Co at room temperature, making it desirable as a so-called conductive material. Fe--Co alloys can be easily produced by heating and melting both metals, but it is more effective to heat and melt them in a non-oxidizing atmosphere. In the case of alloys, oxidation of Fe can be prevented, which is convenient for controlling the quality of the powder. In the present invention, for such a skeleton,
The melting and infiltration of Ag-Te, Ag-Se or Ag-Te-Se alloys into the skeleton is highly desirable for achieving the objectives of the present invention, and that such molten alloys are also carried out in a non-oxidizing atmosphere. The infiltration step is also carried out in a non-oxidizing atmosphere. In the present invention, the above-mentioned Ag alloys melted and infiltrated into the skeleton are Ag alloys containing 3 to 70% Te and/or Se relative to Ag, and if it is less than 3% by weight, the low surge properties will be insufficient. Undesirable. 70 again
If the weight percentage is exceeded, Te or Se alone tends to be liberated and vapor is likely to be generated.Therefore, arcing is likely to occur and the vacuum capacity is reduced, which is disadvantageous. Ag and Te or
Se seems to be stabilized in the compound states of Ag ₂ -Te and Ag ₂ -Se. In the present invention, electrodes are manufactured by infiltrating the skeleton with the above-mentioned Ag-based alloy, but this is based on the fact that metal Co and metal Ag do not form a solid solution. Pressure impregnation can be advantageously used. Further, the amount of Ag-based alloy to be permeated and impregnated is 10 to 80% by weight based on the skeleton. If it is less than 10% by weight, the low surge property and vacuum shredding current effect will be poor, and if it exceeds 80% by weight, arcing will occur through the steam when the shriveling current occurs, making shredding impossible, which is disadvantageous. . The electrode according to the present invention has extremely low surge properties and high vacuum resistance, and is highly practical.
Fe-Co alloys generally have good conductivity at room temperature, but
It has the properties of a current-limiting material whose electrical resistance rapidly increases and its conductivity decreases at high temperatures. Therefore, the increase in electrical resistance at high temperatures causes the temperature of the electrode surface to rise. However, this property actually stabilizes the Ag-based infiltrated alloy,
It is presumed that the effect of reducing the cutting current can be obtained. In manufacturing the electrode according to the present invention, Fe--Co alloy powder can be easily made gas-free by reduction, degassing, etc., and has excellent formability and machinability. Furthermore, it was confirmed that the molten metal of the Ag-based infiltration alloy has good permeability, easily penetrating into the pores of the skeleton, and filling and impregnating approximately 96 to 98% of the pores with the molten metal. Although the porosity of the skeleton used for manufacturing the electrode of the present invention is not so important, it is generally 15 to 60%, preferably 30 to 55% for ease of manufacture. Porosity is the particle size of skeleton molding powder,
It can be easily controlled by molding temperature, especially molding pressure. In order to obtain a skeleton with high porosity, molding can be performed at low molding pressure;
It is more effective to add Ag powder to the skeleton molding powder in advance. Adding Ag powder is effective in increasing infiltration properties, but it is not a good idea. The infiltration alloy is preferably made into a master alloy in order to be gas-free. For example, mother alloying can be done by melting Ag in a vacuum, immediately filling it with Ar gas, and adding Te, Se, etc. in the Ar gas atmosphere.
This can be done while preventing their evaporation loss. This method is possible when the content of Te and Se relative to Ag is 10% or less; if the content exceeds 10%, the evaporation of the added metals is severe and difficult. If the amount is 10% or more, a method is used in which Ag, Te, and Se raw materials are placed in a vacuum-sealed quartz tube and heated and melted and solidified within the tube. The electrode according to the present invention, which has a skeleton with a porosity of 40 to 50% impregnated with an infiltration alloy, is extremely practical because of its performance and ease of manufacture. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 Electrolytic Fe 1.5 kg and electrolytic Co 1.5 kg 1 to 5 times
It was high frequency melted under a vacuum of 10 ^-5 torr and cast into all molds. This alloy was ground into powder of 200 mesh under. This powder is 30mm in diameter x 30mm in height.
It was placed in a mold and compression molded at a pressure of 1.5 to 2.0 ton/cm ² , sintered in hydrogen gas at a temperature of 900 to 950°C, and then vacuum degassed at a temperature of 950 to 1000°C. The residual porosity of the obtained Fe-50Co alloy powder compact was approximately 45%. On the other hand, an alloy containing Ag and Te in a weight ratio of 9:1 was placed in a graphite crucible and melted by high-frequency heating under vacuum. After confirming the melting point, the molded skeleton was lowered and immersed in the molten alloy. After pressurizing Ar gas and holding it for about 20 minutes, the skeleton was lifted to the top and cooled in the furnace. The skeleton impregnated molded body obtained in this way has approximately 98% of the pores.
was filled with infiltrated alloy. Figure 1 of the attached drawings shows Fe obtained by the above method.
This is a 125x microscopic photograph of the surface of a -25Co-45Ag-5Te impregnated molded body. In the photo, the large gray-white flat particles are Fe-50Co particles, and the white background is Ag.
The black crystallized substance surrounding Ag is
It is an As ₂ Te compound. The obtained electrode material has a maximum breaking current of
The current was 1.8A, the average value was 0.85A, and the shearing limit was 170%. Examples 2 to 6 and Comparative Examples 1 to 6 Various electrode materials were manufactured in the same manner as in Example 1, but with different metal compositions or amounts of the skeleton and impregnated alloy. For comparison, the electrical performance was examined along with conventionally used electrode materials, and the results are summarized in Table 1 below. The electrical performance test was conducted in the following manner. The electrode shape used for Tetos is 20 mm in diameter x 25 mm in height.
It is. [Severing current] Measured 100 times with a 100V circuit, the largest value among them was shown as the maximum value, and the average of the 100 times was calculated and used as the average value. [Sheathing limit] Apply so that the shearing current increases in steps of about 500 to 1000A, find the current that reaches the shearing limit,
The shearing limit current value of comparison material Ag-70Wc is 100
% (reference value), limit value of other electrode materials as %
It was shown in The test atmosphere was an evacuation set that simulated a vacuum valve.

[Table] From Table 1, Fe-Co-Ag-Te and Se-based electrodes are
It can be seen that the material has lower cutting current characteristics and higher height and cutting performance than comparative electrode materials other than those of the present invention. In particular, Ag- in the (Fe-25Co) skeleton
Materials infiltrated with Te and Se have approximately the same shearing performance as conventional comparative materials, but both the maximum and average values of shearing current are low, and therefore have excellent low surge properties. The electrode of the present invention also has excellent voltage resistance, welding resistance, abrasion resistance, etc., and also has good machinability. In addition, it is extremely advantageous industrially because a large amount of iron can be used as the skeleton and the amount of cobalt can be reduced to half or less.
Further, the metal powder used in the electrode of the present invention has good moldability and has the feature that it can be easily made gas-free by reduction and degassing treatment. In addition, the infiltration amount of Ag-Te and Se in the infiltration molded product is effective when it is 10% by weight or more, and up to about 80% by weight is good.
- By containing one or more of Te and Se in the Te, Se alloy in a range of 3% by weight or more and 70% by weight or less, it is possible to have both low surge properties and high breakability.

[Brief explanation of the drawing]

FIG. 1 is a partial micrograph showing the metal structure of one example of the electrode of the present invention. In the photo, the gray areas are Fe-50Co particles, the white areas are Ag particles, and the black areas are Ag ₂ Te compounds.

Claims (1)

[Claims] 1 Ag-Te, Ag-Se or Ag-Te-Se in powdered Fe and Co mixture or Fe-Co alloy powder sintered body
An electrode for vacuum insulation and disconnection, characterized by being impregnated with an alloy. 2. After molding powdered Fe and Co mixture or Fe-Co alloy powder dissolved in a non-oxidizing atmosphere,
The sintered body is sintered in a non-oxidizing atmosphere, and Ag--Te, Ag which has been previously dissolved in the non-oxidizing atmosphere is added to the sintered body.
- A method for manufacturing a vacuum shield or disconnection electrode characterized by infiltrating a molten Se or Ag-Te-Se alloy. 3 The sintered body is Fe-Co containing 25 to 75% by weight of Co.
The amount of infiltration of the Ag alloy containing Fe and/or Se3 to 70% by weight into the molten compact is
3. The method of manufacturing a vacuum shield electrode for a breakout according to claim 2, wherein the sintered body is impregnated with the sintered body in an amount ranging from 10 to 80% by weight. 4. The vacuum chamber according to claim 2 or 3, characterized in that the penetration of the molten Ag alloy into the Fe-Co sintered body is carried out by forced pressure impregnation using a non-oxidizing gas. and a method for manufacturing disconnector electrodes.