JP6068127B2 - Contact material for vacuum valves - Google Patents

Description

  Embodiments described herein relate generally to a contact material for a vacuum valve used in a low surge type vacuum valve.

  Conventionally, Ag-WC-based contact materials are known to suppress a surge voltage generated at the time of interruption. This is supposed to suppress the cutting current by a synergistic effect of the thermoelectron emission effect of WC and the vapor pressure of Ag. On the other hand, in the production by a sintering method or the like, about 1 wt% of a sintering aid such as Co or Ni is added in order to achieve high density and low gas (for example, see Patent Document 1). ).

  However, if the sintering aid is too small, the sinterability is not improved and it is difficult to increase the density. Conversely, when the sintering aid is excessive, the bondability by brazing is reduced. For this reason, although a sintering aid is added to the Ag-WC-based contact material, it has been desired to increase the density and improve the bondability. Note that by increasing the density, it is possible to prevent gas reduction or cracking at the time of interruption, and to improve the interruption characteristics. Further, the bonding strength improves the bonding strength between the electrode and the current-carrying shaft, and can prevent the contact from falling off.

JP-A-5-74284

  The problem to be solved by the present invention is to provide a contact material for a vacuum valve capable of improving the bondability as well as increasing the density, although a sintering aid is added to the Ag-WC contact material. .

In order to solve the above-described problem, the vacuum valve contact material of the embodiment is a vacuum valve contact material used for a vacuum valve having a pair of contactable and separable contacts, and the contact is a first contact surface. An Ag-WC-based alloy layer and a second Ag-WC-based alloy layer connected to the first Ag-WC-based alloy layer and fixed to the electrode made of electrolytic copper by brazing ; A sintering aid is added to each of the first Ag—WC alloy layer and the second Ag—WC alloy layer, and the first Ag—more than the second Ag—WC alloy layer. -The amount of the sintering aid added to the WC alloy layer is increased.

Sectional drawing which shows the structure of the contact using the contact material for vacuum valves which concerns on Example 1 of this invention. The figure explaining the manufacturing method of the contact material for vacuum valves which concerns on Example 1 of this invention. The figure explaining the manufacturing method of the contact material for vacuum valves which concerns on Example 2 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a contact material for a vacuum valve according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a contact using a vacuum valve contact material according to Embodiment 1 of the present invention, and FIG. 2 illustrates a method for manufacturing a vacuum valve contact material according to Embodiment 1 of the present invention. It is a figure to do. In addition, in the vacuum valve which has a pair of contact which can be contacted / separated, it demonstrates using one contact.

  As shown in FIG. 1, the contact 1 includes a disk-shaped first Ag—WC alloy layer 2 serving as a contact surface, and a disk-shaped first Ag-WC alloy layer 2 connected to the first Ag—WC alloy layer 2. 2 Ag—WC alloy layer 3. Each of the alloy layers 2 and 3 uses Ag as a conductive component, WC as an arc-proof component, and a sintering aid is added, so that the first Ag-WC alloy layer is more than the second Ag-WC alloy layer 3. The amount of sintering aid 2 is increased. For example, an electrode 4 made of electrolytic copper that generates a longitudinal magnetic field is fixed to the second Ag—WC alloy layer 3 by brazing. An energizing shaft 5 made of electrolytic copper is fixed to the electrode 4 by brazing at the center in the axial direction.

  Next, a manufacturing method will be described with reference to FIG.

  As shown in FIG. 2 (a), first, a mold 50 having a diameter of 50 mm is prepared. Ag powder having an average particle diameter of 2 μm and WC powder having an average particle diameter of 1 μm are set to a mass ratio of 1: 1. Add 0.5 mass% of Co and mix. The first Ag—WC—Co mixed powder 7 is filled in the bottom of the mold 6. Next, Ag powder having an average particle diameter of 2 μm and WC powder having an average particle diameter of 1 μm are set to a mass ratio of 1: 1, and 3.0 mass% of Co as a sintering aid is added and mixed. The second Ag—WC—Co mixed powder 8 is filled on the first Ag—WC—Co mixed powder 7 so as to form two layers. The mass ratio of the first and second Ag—WC—Co mixed powders 7 and 8 is 2: 3.

  Next, as shown in FIG.2 (b), it pressurizes by 7 ton / cm <2>, and the 1st Ag-WC-Co green compact 9 and the 2nd Ag-WC-Co green compact 10 are obtained. These green compacts 9 and 10 are solid-phase sintered in a hydrogen atmosphere under conditions of 950 ° C. × 2 hours and processed into contacts 1 of φ45 mm × t3 mm. Thickness shall adjust the filling amount of the 1st, 2nd Ag-WC-Co mixed powder 7 and 8. After the processing, the electrode 4 is brazed to the first Ag—WC—Co green compact 9 (corresponding to the second Ag—WC alloy layer 3) side. The contact surface is the second Ag—WC—Co green compact 10 (corresponding to the first Ag—WC alloy layer 2).

  Thereby, in the 1st Ag-WC system alloy layer 2 used as a contact surface, Co of a sintering auxiliary material is as large as 3.0 mass%, and it can accelerate | stimulate densification. And resistance to an arc improves, a crack and a crack can be prevented, gas amount can be suppressed, and the interruption | blocking characteristic can be improved. In the second Ag—WC alloy layer 3, Co is as low as 0.5 mass%, and the bonding property with the electrode 4 can be improved. If the sintering aid is approximately 1 mass% as a boundary, and the amount is higher than this, the density can be increased, and if it is less, the bondability can be improved.

  Further, since the powder is mixed and sintered at the interface between the first Ag—WC alloy layer 2 and the second Ag—WC alloy layer 3, the alloy layers 2 and 3 are firmly connected to each other. be able to. Furthermore, since the thickness of the first Ag—WC alloy layer 2 is larger than that of the second Ag—WC alloy layer 3, it is possible to give a margin to contact wear due to arc.

  According to the contact material for the vacuum valve of Example 1 described above, the second Ag—WC alloy is bonded to the electrode 4 with a large amount of the sintering aid of the first Ag—WC alloy layer 2 serving as the contact surface. Since the sintering aid of the layer 3 is reduced, the densification can be promoted on the contact surface, and the joining property can be improved on the joining surface.

  In Example 1 above, Co is used as the sintering aid, but at least one of Ni, Fe, and Cr can be used.

  Moreover, although WC was used for the arc resistant component, one or more of Mo2C, NbC, TaC, TiC, VC, ZrC, and HfC can be mixed.

  Next, contact materials for vacuum valves according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a view for explaining a method for manufacturing a contact material for a vacuum valve according to Embodiment 2 of the present invention. The second embodiment is different from the first embodiment in the contact manufacturing method. Since the configuration of the contacts is the same as that of the first embodiment, description thereof is omitted.

  As shown in FIG. 3A, first, WC powder having an average particle diameter of 1 μm and Ni powder having an average particle diameter of 2 μm are mixed at a mass ratio of 99: 1 and molded at 3 ton / cm 2. The green compact is sintered in a hydrogen atmosphere at 900 ° C. for 1 hour to obtain a WC—Ni temporary sintered body 11. Next, Ag-Ni mixed powder 12 obtained by mixing Ag powder having an average particle diameter of 2 μm and Ni powder having an average particle diameter of 2 μm at a mass ratio of 97: 3 is placed on the temporary sintered body 11. This is heat-treated in a hydrogen atmosphere under conditions of 1150 ° C. × 1 hour, and the Ag—Ni mixed powder 12 is infiltrated into the WC—Ni sintered body 11. After the infiltration, as shown in FIG. 3B, a first Ag—WC—Ni alloy layer 13 with a low Ni content and a second Ag—WC—Ni alloy layer 14 with a high Ni content can be obtained. it can.

  This is processed into a contact 45 of φ45 mm × t3 mm so that the second Ag—WC—Ni alloy layer 14 side becomes a contact surface. After the processing, the electrode 4 is brazed to the first Ag—WC—Ni alloy layer 13 side. When wet analysis was performed, the Ni content of the first Ag-WC-Ni alloy layer 13 was 0.7 mass%, and the Ni content of the second Ag-WC-Ni alloy layer 14 was 2.5 mass%. . The WC was approximately 60 mass% in the second Ag—WC—Ni alloy layer 14. In addition, the Ag—Ni mixed powder 12 and the like are adjusted so that the second Ag—WC—Ni alloy layer 14 serving as the contact surface is thicker than the first Ag—WC—Ni alloy layer 13.

  As a result, even in the infiltration method, the amount of Ni added to the second Ag—WC—Ni alloy layer 14 (corresponding to the first Ag—WC alloy layer 2) serving as the contact surface can be increased, and the density can be increased. As a result, the amount of Ni added to the first Ag—WC—Ni alloy layer 13 (corresponding to the second Ag—WC alloy layer 3) can be reduced, and the bondability can be improved.

  According to the vacuum valve contact material of the second embodiment, the same effect as that of the first embodiment can be obtained by the infiltration method.

  In Example 2 above, Ni was used as the sintering aid, but at least one of Co, Fe, and Cr can be used.

  According to the embodiment of the present invention, the contact surface has a large amount of sintering aid and can be densified, and the joining surface has a small amount of sintering aid and can improve the joining property. .

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Contact 2 1st Ag-WC system alloy layer 3 2nd Ag-WC system alloy layer 4 Electrode 5 Current supply axis

Claims (6)

In a vacuum valve contact material used for a vacuum valve having a pair of contactable and separable contacts,
The contact, a first Ag-WC alloy layer serving as a contact surface;
The second Ag-WC alloy layer is connected to the first Ag-WC alloy layer and fixed to the electrode made of electrolytic copper by brazing .
A sintering aid is added to each of the first Ag—WC alloy layer and the second Ag—WC alloy layer,
A contact material for a vacuum valve, wherein the amount of the sintering aid added to the first Ag-WC alloy layer is larger than that of the second Ag-WC alloy layer.   The contact material for a vacuum valve according to claim 1, wherein the first Ag-WC alloy layer and the second Ag-WC alloy layer are formed by a sintering method.   The contact material for a vacuum valve according to claim 1, wherein the first Ag-WC alloy layer and the second Ag-WC alloy layer are formed by an infiltration method.   The contact material for a vacuum valve according to any one of claims 1 to 3, wherein the sintering aid is at least one of Co, Ni, Fe, and Cr.   5. The vacuum valve use according to claim 1, wherein the first Ag—WC alloy layer is thicker than the second Ag—WC alloy layer. 6. Contact material.   The contact material for a vacuum valve according to any one of claims 1 to 5, wherein at least one of Mo2C, NbC, TaC, TiC, VC, ZrC, and HfC is mixed with the WC.

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