JPS60131723A - Method of producing contact material for vacuum breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to vacuum pulp, and more particularly to an improvement in a method for manufacturing a contact material thereof.

[Technical overview of the invention and its problems]

As is well known, Shin-Ame 1 and the circuit breaker have superior characteristics compared to other circuit breakers such as being small, lightweight, maintenance-free, and environmentally friendly, so the scope of their application has rapidly expanded. %, zru. The basic requirements for such a vacuum breaker contact 1i are (1) low weldability;
(2) high withstand voltage, (3) good disconnection performance, and in addition, low disconnection current value;
Low contact resistance, low beam stability, and good wear resistance are also requirements for military spending.

However, these requirements are inevitably contradictory, and it is impossible to satisfy all of them with a single metal. Therefore, as a single material that can be put into practical use, it is a combination of two or more elements that mutually compensate for the lacking properties, and a contact that is limited to a specific application such as for large current or withstand voltage. Monthly products have been developed, and products with excellent properties are being commercialized, but even more
At present, a contact material that fully satisfies the requirements for Hatake withstand voltage or Tenryu current has not yet appeared. □゛For example, bismuth (Di
) Copper-bismuth (Cu-Bi) alloys containing 5% or less of bath adhesion prevention components are known (Japanese Patent Publication No. 41-1
2131 (Publication), because the solubility of bismuth (Bi) in the copper (CI) matrix is extremely low, segregation often occurs1, and the surface of the breaker becomes slightly larger, making it difficult to process and form the cylinder. Contains some problems. .

In addition, as another contact material different from the above, copper-terel (Cu
-Te) alloy is also known (Japanese Patent Publication No. 44-23751
Publication No.). In this alloy, Cu-11i
) type contact materials have been alleviated, but compared to copper-bismuth (Cu-Bi) type contact materials, they are more sensitive to the atmosphere, resulting in poor stability in terms of contact resistance, etc. Lacking. Furthermore, these copper-bismuth (Cu-Bi
), Cu-Te 7% alloys have excellent adhesion resistance, but their voltage resistance characteristics are not suitable for applications up to the conventional medium voltage class. , is sufficient, but it has become clear that it is not necessarily satisfactory for application to higher pressure fields (in other words, miniaturization of vacuum breakers, especially vacuum valves).

Among the above-mentioned drawbacks, tungsten (W), tungsten carbide (WC,
) and effectively utilizes copper (cu) and silver (Ag) to improve conductive properties.
), tungsten carbide-silver (WC-Ag), and other alloys are known. These alloys have excellent recovery voltage characteristics against currents that exceed 0 to 20, but above this current value, tungsten (W), which has become hot due to arc heat, etc. A large amount of thermionic electrons are emitted from tungsten carbide (W, etc.), which inhibits recovery of dielectric strength after current extinction.

On the other hand, chromium (C''), titanium (Ti), vanadium (
copper, zirconium (Zr), etc., copper (Cu), silver (Ag), etc.
) etc., the above-mentioned tungsten (W)
, thermionic emission is reduced compared to tungsten carbide (WC), so the problems caused by it are reduced.

Among the above-mentioned contact materials, copper-His-Q (Cu-Bi) manufactured by a melting method 1. Copper-te L/ /
In l/(Cu-Te) based alloys, the crucible-like container that houses the material or alloy during melting is often made of carbon, aluminum oxide, silicon oxide, etc., and is used repeatedly.

On the other hand, any one of chromium (Cr), titanium (Ti), vanadium (T), or zirconium (Zr)
For contact materials containing two elements, in any one of heat treatment, sintering, or infiltration, the container such as a crucible or boat containing the contact material, mixture, or molded material may contain carbon, aluminum oxide, silicon oxide, Silicon nitride exhibits a reaction or wetting phenomenon, and repeated use is often difficult and uneconomical, as well as damage to the contact material, mixture, or molded object, and reaction products. This change may cause changes in the characteristics of the contact material or cause fluctuations. p' 豐＜Requested ・Vacuum breakers have been expanded to include power supply systems such as magnetic networks and large plants, especially in congested urban areas, where high reliability is most required. Therefore, the emergence of a contact alloy with stable contact characteristics without any variation has become an important issue, including its manufacturing method.

[Purpose of the invention]

The present invention has been made in view of the above points, and is based on copper (Cu).
) and silver (Ag), chromium ('')
, titanium (Ti), vanadium (T), or zirconium (Zr), which can be manufactured with high quality and economically. [Summary of the Invention] The present invention provides at least one of copper (Cu) and silver (Ag), chromium (Or), titanium (Crt), and vanadium (V
) or zirconium (Zr) is subjected to at least one of heat treatment, sintering, or infiltration in hydrogen or vacuum, the above mixture or molded body and the container that houses them,
Aluminum oxide (A4 Om), magnesium oxide (Mg0), acid oxide (Cry 0B), zirconium oxide (ZrO,), silicon nitride (si, Na), boron nitride (Cry 0B), preheated at at least 400 °C. The main component is one of heat-resistant inorganic particles selected from aluminum nitride (A/N), aluminum nitride (A/N), etc.
This is a method for producing an economical and high quality contact material for a vacuum breaker using an intermediate object having an average particle size of 0IIm.

[Embodiments of the invention]

The present invention will be explained in detail below.

Copper-Ti 0 A (Cu-Cr), Copper-Ti y (Cu
It is known that contact materials such as -Ti), copper-vanadium (Cu-V), and copper-zirconyla A (Cu-Zr) yarns inherently have excellent withstand voltage characteristics in terms of material composition. Due to its particularly active nature, the manufacturing conditions influence the material properties; The inventors' research has revealed that material variations occur due to the reaction of . This reaction is related to the atmospheric conditions during manufacturing (purity of hydrogen or degree of vacuum), the purity of the contact material and container, the degree of surface contamination (oxidation), the degree of built-in gas or adsorbed gas, etc., but most The desired contact material cannot be obtained due to reaction or stagnation with the material of the container. According to the observations of the present inventors, when the above-mentioned atmospheric conditions and other conditions are met, complete swirling or reaction results in firm adhesion. In particular, it has been observed that significant wetting or reaction occurs when there is direct contact over a large area, such as when contact materials, mixtures or molded bodies come into contact with a plate-shaped container. This suggests the importance of reducing the formation or presence of active substances such as oxide films that promote turbidity or reactions between the two. At the same time, it also suggests the necessity of preventing direct contact between the two over a large area. - Based on this knowledge, the present invention provides a predetermined gap between contact materials, mixtures, or molded bodies that have been heat-treated at least at 400°C in advance, in order to prevent direct contact over a large area with the container. The heat treatment is performed using a heat-resistant inorganic intermediate having an average particle size of . More specifically, it is a mixture or molded material consisting of at least one of copper (Cu) and silver (Ag) and any one of chromium (''), titanium (TM), vanadium (%Q) or zirconium (Zr). In the case where the body is subjected to at least one of heat treatment, sintering, or infiltration in hydrogen or vacuum, a carbon dioxide heat treatment at at least 400 ° C. Aluminum oxide (
AI! t 0s ) X magne oxide and ram (Mg0),
Chromium oxide (Cr, 01), zirconium oxide (z
rom), silicon nitride (si, Na), boron nitride (
The main component is heat-resistant inorganic particles ')1' selected from aluminum nitride (BN) or aluminum nitride (A/N), etc.
An intermediate object having an average particle size of 0.00 μm is interposed.

As mentioned above, chromium (Cr) containing active properties,
Titanium (T')% Vanadium (V) or Zirconium (
Contact materials containing any one of Zr) are significantly affected by the atmosphere during manufacturing, and if not adequately controlled, bores easily remain inside.

In such contact materials, it is recognized that the disconnection performance and withstand voltage characteristics are significantly deteriorated, and eliminating this bore is an important problem to be solved by the present invention. According to the research conducted by the present inventors, when manufacturing the contact material according to the present invention, when sintering or reaction occurs between the sintered body or molded body and these tight containers, a large number of Boa exists. This phenomenon is due to the fact that during the sintering or infiltration process, the gas present inside the contact alloy surface layer during manufacture is trapped by the progress of sintering before it is fully released to the outside. This is thought to be a major cause of the deterioration of the properties of contact materials and the occurrence of variations in quality.For this reason, the present invention aims to effectively prevent the reaction between contact materials and the container in which they are processed. It can be said that the problem is solved.

On the other hand, in powder metallurgy, heat treatment by immersing the sintered body in aluminum oxide (A4 On ) powder has been adopted as a technique to alleviate the thermal strain that the sintered body undergoes during the sintering process. In the present invention, the kneading technique is utilized and further improved, and the heat-resistant inorganic particles constituting the intermediate object in the present invention have an appropriate particle size to obtain a stable contact material of high quality. The intermediate object is arranged so that the container does not come into direct contact with the contact material, mixture or molded object, and the molten infiltration material (Ql)
Alternatively, it is necessary to provide a sufficient amount (thickness) of the tongs in the molded body to prevent them from reaching the storage container through the gaps between the heat-resistant inorganic particles constituting the intermediate body.

Further, it is necessary to arrange an intermediate object on the side surface of the molded body so as not to obstruct the removal of the gas inside the molded body or the gas on the surface. As a typical example of this arrangement, when placing the infiltrant (Cu) on the lower side and a molded body etc. on the upper side, the above-mentioned intermediate object is placed between the container and the infiltrant, and then It is desirable to have only a portion of the immersion material (Ql) on the side surface and to minimize the amount as much as possible.

The reason for limiting the particle size of the heat-resistant inorganic particles constituting the above-mentioned intermediate object will be explained below with reference to Examples and Comparative Examples.

Comparative Examples 1 to 5 Same as chromium (Cr) with an average particle size of 125 μm
A mixture of copper (Cu) with an average particle size of μm was mixed at 15TON/
An infiltration material made of copper (Ou) was placed on the underside of the pre-sintered body obtained by molding at a pressure of 1,150 °C for 1 hour in a hydrogen atmosphere, and Infiltration is carried out for 1 hour at ℃. At this time, the storage container (boat) for the pre-sintered body was carbon in Comparative Example 1 and aluminum oxide (in Comparative Example 2).
A4 On), Comparative Example 3 is magnesium oxide (Mg
0), Comparative Example 4 is silicon oxide (8i0.), Comparative Example 5
In each case, silicon nitride (si3Na) was used, and in each case, the container, the molded body, and the temporary sintered body were arranged so as to be in direct contact with each other. In all cases, the contact material obtained as a result could not be taken out unless the container f was destroyed. Further, when looking at the metal structure of the cross section, there were many huge pores ranging from several tens of microns to several hundreds of microns, and the material properties were also unfavorable.

Comparative Examples 6 and 7, Examples 1 to 3 The infiltration material was applied to the remaining pores in the same manner as in Comparative Examples 1 to 5 above using a molded body in which the composition of the contact material after infiltration was Cu-50cr. Infiltrate Cu. Temperature and time during temporary sintering and infiltration were 1150°C and 1 hour, and infiltration material C
The temporary sintered body was placed in close contact with u, and between the infiltrant material Cu and the container, aluminum oxide (A4 Om) with an average i of 1 μm was used in Comparative Example 6, and magnesium oxide (A4 Om) with an average i of 125 μm was used in Example 2. In Example 3, 300 μm magnesium oxide (Mg0), and in Comparative Example 7, 600 μm magnesium oxide (Mg0) were placed.

As shown in Table 1, the particle size of the inorganic particles ♦ is 300 μm per day.
In the range of m, the basic properties as a contact material are excellent in terms of the number of bores and the amount of gas formed by the method described later (Examples 1 to 3). On the other hand, it was found that when the inorganic particles were even finer, the amount of gas in the contact material was greater (Bi Kabura 6).

The reason for this is that the surface area (per unit volume) is extremely large due to the fine particles, and there is also a lot of surface adsorption, which causes temporary condensation or partial progress before it is sufficiently removed.
It is presumed that the oxidation of the oxidized body and contact point □ caused gas to remain and the pores to be generated inside.On the contrary, when the inorganic particles were gigantic and had a diameter of 600 μm, 1
However, the gap between the particle and the tube is not filled sufficiently, and the infiltrated copper (Ql) flows out through the gap, and this copper (Cu) reaches the storage container, and the chromium (Cr) in the contact material flows out. ) was used as a medium to react between the infiltrant (Cu) and the container. possible (Comparative Example 7).

For this reason, as in the case of the first gate, pores were present in the contact material and the amount of gas was relatively large.

As described above, there is a suitable particle size for inorganic particles, and by selecting this particle size, it is possible to produce a healthy contact material in the form of a light gray crystal.

The above-mentioned Examples 1 to 3 and Comparative Examples 1 to '7 are applicable to dicopper-chromium (Cu-Cr) alloys, but the present invention applies to other contact assemblies, that is, those shown in Table 2. Child example 4
(7) Copper-titanium (Cu-Ti) alloy, collection of "Copper-1 and Cu-V alloys" in Example "'5" and copper-1 di material in Example 6, Aluminum oxide (A/l O
Similar effects can be obtained not only with zirconium oxide (Zr0.), silicon nitride (SisN4), boron nitride (BN), and aluminum nitride (AI!N).

The above-mentioned method for manufacturing the contact material, in which the mixture is molded and then pre-sintered, and the remaining pores of this sintered body are infiltrated with an infiltrant material, has been shown. Pre-sintering was carried out in hydrogen at 1030°C for 3 hours, followed by sintering at a pressure of 7 TON/ci. +: Obtained by heating in vacuum for 2 hours at 1030 υ after heating, and when aluminum oxide (Ale 0s) particles are not used, contact advantages such as residual pores and gas welfare are obtained as in Comparative Examples 1 to 7. It was found that the basic characteristics of the spines were inferior (Comparative Example 8). On the other hand, when aluminum oxide (Ale On) particles were used, improvements in the basic properties of the contact material such as residual pores and gas amount were observed (Example 9). Therefore, it can be seen that similar effects can be obtained also in solid phase sintering.

In addition, the static withstand voltage characteristics of the contacts are stable at around 70 kV, and the number of sudden sparks observed during the measurement of the static withstand pressure characteristics is small and stable.

This is done by heating the inorganic particles to 400°C (preferably 1000°C).
By using a material that has been heat-treated to a temperature above ℃), variations in material properties and static abrasive pressure properties are reduced and stabilized.
This is thought to be the effect of sufficiently removing adsorbed moisture, etc.

(The following is a blank space) [Note] Evaluation conditions for material properties
Insert into a carbon capsule and extract.

Number of bores; specified area (1
Count the number of bores within 130 μm x 880 μm).

Characteristics of static withstand voltage: A Ni needle electrode finished by separate cloth polishing is used as an anode, and a sample flat plate also finished by separate cloth polishing is used as a cathode, and the voltage is gradually increased in a vacuum of 10 mHH to generate a spark. The voltage value was measured and taken as the voltage at breakdown (kV). The number of sudden (pulse-like) sparks observed until the breakdown voltage was reached was defined as the number of sparks.

[Effects of the Invention] Since the present invention is configured as described above, it is possible to obtain a high quality and economical contact material for a vacuum breaker.

Claims (1)

[Claims] A mixture or composite body consisting of at least one of copper (Cu) and silver (Ag) and any one of chromium (''), titanium ('l'i), vanadium υ or zirconium (Zr), In the case where at least one treatment of heat treatment, sintering or infiltration is performed in hydrogen or vacuum, the soul 4-
Aluminum oxide CAet'os), magnesium oxide A (Mg0), oxidized oxide (Crto3), zirconium oxide'(Z'r0.),'nitrided Silicon (S
The main component is one of heat-resistant inorganic particles selected from boron nitride (BN) and emptied aluminum (AeN), and has an average particle size of 1 to 300 μm. A method for manufacturing a contact material for a vacuum breaker, which is characterized by simply interposing an intermediate object with a container and performing at least one treatment of heat treatment, sintering, or infiltration.