JP2009113089A - Joining material for vacuum valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a joining material for a vacuum valve which can firmly join stainless parts composing a vacuum valve. <P>SOLUTION: In the joining material for a vacuum valve, which joins stainless parts composed of an arc shield 11, a support 12, bellows 10, and sealing fittings 2, 3 in a vacuum valve having a pair of contacts 6, 7 which can freely approach/separate in a vacuum, an Ni-containing substance is made present in the brazing filler metal in the vicinity of the stainless parts when a brazing filler metal is melted at a prescribed temperature, so as to be solidified and brazed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a joining material for a vacuum valve for brazing stainless steel parts such as arc shields and bellows and copper parts such as current-carrying shafts.

  Conventionally, for joining stainless steel parts of vacuum valves, 1 to 10% by weight of Sn, 2.5 to 10% by weight of Cu, the balance being made of Ag, and 1 to 10% by weight of Sn, 2.5 There is known a joining technique using a brazing material composed of -10 wt% Cu, 6 wt% or less Mn, and the balance Ag.

Further, the bonding phase is at least one of 90% by weight or more of Ag and 10% by weight or less of Cu, 8% by weight or less of Ag, 5 to 35% by weight of Cu, and the balance being Ni or Sn. There is known a joining technique comprising a second phase comprising (for example, see Patent Document 2).
JP 2002-361478 A (3rd page, FIG. 1) JP 2005-209578 A (Page 4, FIG. 1)

  In order to fully exert the function of the vacuum valve, it is desirable that the joint portion by brazing does not peel or separate due to mechanical and thermal shocks when the electrode is opened and closed. However, with conventional joints, there is little consideration for the phenomenon of crack growth from the brazing filler metal edge during frequent opening and closing, resulting in misalignment of the joints and the inability to maintain airtightness. In some cases, required properties such as For this reason, this invention paid attention to Ni contained in a brazing material, and examined bondability.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vacuum valve bonding material capable of firmly bonding a bonded portion.

  In order to achieve the above object, the vacuum valve bonding material of the present invention is a vacuum valve bonding material for bonding stainless steel parts constituting the vacuum valve, and is brazed by melting and solidifying the brazing material at a predetermined temperature. In some cases, a material containing Ni is present in the brazing material in the vicinity of the stainless steel part.

  According to the present invention, when the brazing material is melted and solidified, since the substance containing Ni supplied from the brazing material or stainless steel is present in the joint portion, the affinity with the stainless steel is increased, and the wetting spreads. As a result, it is possible to improve the reliability of the vacuum valve.

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

  A vacuum valve bonding material according to an embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view showing a configuration of a vacuum valve according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a configuration of one contact of a vacuum valve according to an embodiment of the present invention, and FIG. It is an expanded sectional view explaining the junction part of the vacuum valve which concerns on an Example.

  First, a vacuum valve using a vacuum valve bonding material will be described. As shown in FIG. 1, a fixed-side sealing fitting 2 and a movable-side sealing fitting 3 are sealed by brazing on both end opening surfaces of a cylindrical vacuum insulating container 1. A fixed-side energizing shaft 4 is fixed through the fixed-side sealing fitting 2, and a fixed-side electrode 5 and a fixed-side contact 6 are fixed to the ends. Opposite to the fixed side contact 6, a movable side contact 7 that can be contacted and separated is fixed to the movable side electrode 8. The movable side electrode 8 is fixed to the end of the movable side energizing shaft 9 movably penetrating the central opening of the movable side sealing fitting 3. An expandable / contractible bellows 10 is sealed between the opening of the movable side energizing shaft 9 and the movable side sealing fitting 3 by brazing.

  Thereby, the movable contact 7 can be brought into contact with and separated from the fixed contact 6 while keeping the inside of the vacuum insulating container 1 in a vacuum. An annular support 12 is brazed to the outer periphery of the cylindrical arc shield 11 that surrounds the contacts 6 and 7, and is fixed to a protruding portion that protrudes from the inner surface of the vacuum insulating container 1.

  As shown in FIG. 2, the stationary contact 6 is fixed to the stationary electrode 5 by a brazing portion 13. The fixed side electrode 5 and the fixed side energizing shaft 4 are fixed by a brazing portion 14 or are crimped and connected by caulking. The movable side has the same configuration.

  Here, the arc shield 11, the support 12, the bellows 10, and the sealing fittings 2 and 3 are made of stainless steel or an alloy containing stainless steel, and these are called stainless steel parts of the vacuum valve.

  Next, a method for assembling such a vacuum valve will be described. The vacuum valve seals the vacuum insulating container 1 and the sealing fittings 2 and 3 by combining the process of partially assembling the contacts 6 and 7 and the electrodes 5 and 8, the arc shield 11 and the support 12, and the partially assembled parts. It is manufactured in the whole sealing process. The partial assembling process and the entire sealing process may be manufactured by two-stage brazing using brazing materials having different melting temperatures, or may be manufactured by brazing these processes simultaneously. Here, the partial assembly process and the entire sealing process were performed simultaneously.

  Next, a method for evaluating a brazing material as a bonding material will be described. As shown in FIG. 3, the copper plate 15 and the stainless steel plate 16 are joined by the brazing material 17 composed of various materials shown in Table 1, and the brazing material matrix and stainless steel existing in the vicinity of the stainless steel plate 16 in the brazing material 17 are apparent. A substance 18 containing Ni having a different tissue form was examined with an electron microscope and an attached semi-quantitative analyzer. In addition, after performing mechanical opening and closing 1000 times with a vacuum valve joined with a brazing material of the same material, the to-be-joined part was observed with X-rays, and the withstand voltage characteristics were obtained in order to investigate the airtightness.

  Hereinafter, the results when the components in the brazing material 17 and the heat treatment conditions are changed will be described with reference to Table 1.

(Comparative Examples 1 and 2 and Examples 1 to 3)
In Comparative Example 1, BPd-2 (Ag-31.5 wt% Cu-10 wt% Pd, hereinafter omitted wt%) containing 10 wt% of Pd which is a noble metal element was used as the brazing material 17 and 900 Heat treatment was performed in a vacuum at 0 ° C. The stainless steel plate 16 was subjected to Ni plating, but no substance containing Ni was detected in the brazing material 17. Further, in the evaluation of the vacuum valve, the joining of the arc shield 11 / support 12 plated with Ni was good, and the withstand voltage characteristics after the open / close test were also good. This withstand voltage value was defined as a reference value (1.0), and was shown as a relative value in the following comparative examples and examples. The stainless steel plate 16 is made of the same material as the arc shield 11 or the like.

  In Comparative Example 2, Ag-28Cu (eutectic silver brazing) was used as the brazing material 17 and heat treatment was performed in a vacuum at 900 ° C. On the unplated stainless steel plate 16, a substance containing Ni was not detected, and the arc shield 11 of the unplated arc shield 11 / support 12 was dropped immediately after manufacture in the evaluation of the vacuum valve.

  In Examples 1 to 3, Cu-10Ag, Cu-25Ag, and Cu-50Ag were used as the brazing material 17, and heat treatment was performed in a vacuum at 900 ° C. In the vicinity of the unplated stainless steel plate 16, a substance 18 containing Ni was detected, and its component was Cu-Ni. This is what Ni was supplied from stainless steel. In the evaluation of the vacuum bulb, the arc shield 11 / support 12 without plating was good and did not fall off in the open / close test, and the withstand voltage characteristics were 1.1 times each. The term “no plating” means that the stainless steel substrate is exposed.

(Examples 4 to 6)
In Example 4, Cu-15Sn was used as the brazing material 17, Ag-20Sn was used in Example 5, Ag-28Cu-1Ni was used in Example 6, and heat treatment was performed in a vacuum at 900 ° C. In the vicinity of the stainless steel plate 16, a substance 18 containing Ni was detected, and its components were Cu—Ni—Sn and Ni—Sn. In this case, Ni is supplied from a brazing material or stainless steel. In the evaluation of the vacuum valve, the arc shield 11 / support 12 without plating did not fall off in the open / close test, and the withstand voltage characteristics were 1.1 times each.

  In Examples 4 to 6, Sn and Ni have been described as additive elements, but the same effect can be expected by adding one or more of four types of elements including In and Ti. In particular, if the total amount of the additive elements is 20% by weight or less, the strength reduction of the brazing material 17 itself can be suppressed, so that the effect is significant.

(Examples 7 to 9)
In Examples 7 to 9, Ag-28Cu-1Sn-1Ni was used as the brazing material 17 and heat treatment was performed in an inert atmosphere such as a hydrogen atmosphere at 900 ° C., an argon atmosphere, and a nitrogen atmosphere. In the vicinity of the stainless steel plate 16, a substance 18 containing Ni was detected, and its component was Cu—Ni—Sn. In the evaluation of the vacuum valve, the unshielded arc shield 11 / support 12 did not fall off in the open / close test, and the withstand voltage characteristics were each 1.0 times or more. Moreover, the appearance of the brazing material 17 was good and showed a metallic luster.

(Comparative Examples 3-4, Examples 10-12)
In Comparative Example 3, Ag-28Cu-1Sn-1Ni was used as the brazing material 17 and was heat-treated in a vacuum at 955 ° C. In Examples 10 to 12, Ag-28Cu-1In-1Ni was used as the brazing material 17 and heat treatment was performed in a vacuum at 950 to 700 ° C. In Comparative Example 4, Ag-28Cu-1In-1Ni was used as the brazing material 17 and heat treatment was performed in a vacuum at 680 ° C.

In Comparative Example 3, a trace of partial melting of the surface of the silver-based part constituting the vacuum valve was observed, and it was determined that it was not suitable for the product, and the evaluation of the vacuum valve was stopped. This is presumed that the heat treatment temperature of 955 ° C. was close to the melting temperature of pure silver of 961 ° C. and was influenced by this. (A combination of the fact that the true temperature rises due to overheating even when the heat treatment temperature is 955 ° C., and the melting temperature is lowered due to the incorporation of impurities into the silver-based parts)
In Examples 10-12, the substance 18 containing Ni was detected in the vicinity of the stainless steel plate 16, and the component was Cu-Ni-In. In the evaluation of the vacuum valve, the arc shield 11 / support 12 without plating did not drop off in the open / close test, and the withstand voltage characteristics were 1.1 times or more respectively. In Comparative Example 4, the melting temperature was low, the arc shield 11 dropped during the open / close test, and the withstand voltage characteristics were not required due to irregular discharge.

(Examples 13 to 16)
In Examples 13 to 16, Cu-25Ag-1Ti-1Ni was used as the brazing material 17, and heat treatment was performed in a vacuum at 900 ° C. In Example 13, the non-plated stainless steel part bellows 10 and the copper part movable side energizing shaft 9, in Example 14, the unplated bellows 10 and the stainless steel movable side metal fitting 3, and in Example 15, the fixed side sealing. The metal fitting 2 and the fixed-side energizing shaft 4 for the copper part, in Example 16, the sealing metal fittings 2 and 3 and the vacuum insulating container 1 (sealing treatment of the sealing surface with Mo-Mn metallization and Ni plating) were joined. In both cases, a substance 18 containing Ni was detected in the vicinity of the stainless steel plate 16, and the component thereof was Cu—Ni—Ti. In the evaluation of the vacuum valve, each part did not fall off in the open / close test, and the withstand voltage characteristics were 1.1 times each.

According to the vacuum valve bonding material of the above embodiment, when the brazing material 17 is melted and solidified, the substance 18 containing Ni supplied from the brazing material 17 and the stainless steel plate 16 exists in the brazing material 17. As a result, the affinity with the stainless steel plate 16 is increased, the joining properties such as the wet spreadability and the joining strength are improved, and the joining parts such as the stainless parts, the copper parts, the ceramics can be firmly joined, A vacuum valve having good opening / closing characteristics and withstand voltage characteristics can be provided.

Sectional drawing which shows the structure of the vacuum valve which concerns on the Example of this invention. Sectional drawing which shows the structure of one contact of the vacuum valve which concerns on the Example of this invention. The expanded sectional view explaining the junction part of the vacuum valve which concerns on the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum insulation container 2 Fixed side sealing metal fitting 3 Movable side sealing metal fitting 4 Fixed side energizing shaft 5 Fixed side electrode 6 Fixed side contact 7 Movable side contact 8 Movable side electrode 9 Movable side energizing shaft 10 Bellows 11 Arc shield 12 Support 13 , 14 Brazing part 15 Copper plate 16 Stainless steel plate 17 Brazing material 18 Material containing Ni

Claims (8)

A joining material for a vacuum valve for joining stainless steel parts constituting a vacuum valve,
A bonding material for a vacuum valve, characterized in that a substance containing Ni is present in the brazing material in the vicinity of the stainless steel part when the brazing material is melted and solidified at a predetermined temperature.   2. The bonding material for a vacuum valve according to claim 1, wherein the brazing material is either Cu or Ag as a main component.   The said brazing | wax material contains at least 1 sort (s) of Sn, Ni, In, Ti, The joining material for vacuum valves of Claim 1 or Claim 2 characterized by the above-mentioned.   4. The bonding material for a vacuum valve according to claim 1, wherein the substance containing Ni is a Cu—Ni system or a Cu—Ni—Sn system. 5.   The said brazing material is used in inert atmosphere, The joining material for vacuum valves of any one of Claim 1 thru | or 4 characterized by the above-mentioned.   The joining material for a vacuum valve according to any one of claims 1 to 5, wherein the brazing material is heat-treated at a temperature of 700 to 950 ° C.   The said stainless steel part is an arc shield, a support, a bellows, and a sealing metal fitting, The joining material for vacuum valves of any one of Claim 1 thru | or 6 characterized by the above-mentioned.   The joining material for a vacuum valve according to any one of claims 1 to 7, wherein the stainless steel part is not plated with Ni.

Images