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Publication numberUS3770497 A
Publication typeGrant
Publication dateNov 6, 1973
Filing dateMar 25, 1971
Priority dateMar 26, 1970
Also published asDE2014638A1
Publication numberUS 3770497 A, US 3770497A, US-A-3770497, US3770497 A, US3770497A
InventorsHassler H, Schreiner H
Original AssigneeSiemens Ag
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of producing a two layer contact piece
US 3770497 A
Abstract
The invention relates to a method of producing a two layer contact piece for high vacuum power switches. An auxiliary metal and a diffusion metal are alloyed by diffusion into a surface of a metallic original body of high electrical conductivity. The auxiliary metal forms a molten phase with the diffusion metal and the metallic original body. The volume of auxiliary metal provides a defined diffusion depth in the original body, at predetermined diffusion conditions.
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United States Patent 1 1 1111 3,770,497 Hassle!- et al. 1 1 Nov. 6, 1973 [54] METHOD OF PRODUCING A TWO LAYER 2,379,232 6/1945 Henscl 29/630 C C N PIECE 3,008,022 11/1961 Lee 200/166 C X 3,610,859 10/1971 Schrcincr et al 200 166 c [75] Inventors: Heinrich Hassler, Wendelstem; 3,502,465 3 1970 Nakaji a 200 166 c x Horst Schreiner, Nurnberg, both of 3,596,027 7/1971 Okutomi et a]. 200/166 C X Germany [73] Assignee: Siemens Aktiengesellschafl, Berlin Primary Examiner Ra|ph Kendall and Mumch Germany Attorney-Curt M. Avery, Arthur E. Wilfond, Herbert 22 i 25 1971 L. Lerner and Daniel J. Tick [21] App]. No.: 128,060

[30] Foreign Application Priority Data [57] ABSTRACT Mai 26, 1970 Germany P 20 14 633-7 The invention relates to a method of producing a two layer contact piece for high vacuum power switches. l l Cl 117/227 An auxiliary metal and a diffusion metal are alloyed by 200/166 CM, 200/144 B, 29/630 C diffusion into a surface of a metallic original body of [51] Int. Cl. HOlh 33/66 high electrical conductivity The auxiliary meta] forms [58] Field of Search 1 17/212, 227, 22; a molten phase with the diff i metal and the metal- 29/622, 630 (3; 200/166 C, 166 CM; 1 lic original body. The volume of auxiliary metal provides a defined diffusion depth in the original body, at [56] References C'ted predetermined diffusion conditions.

UNITED STATES PATENTS 2,049,771 8/1936 Gwyn, Jr 200/166 C X 6 Claims, 5 Drawing Figures METHOD OF PRODUCING A TWO LAYER CONTACT PIECE The present invention relates to a method of producing a two layer contact piece for high vacuum power switches.

Contact materials for high power switches are required to have extremely low amounts of gas, small chopping effects, small welding power and low contact resistance. Also needed is a low burn-off. The chopping effect causes the arc to break or be interrupted during the switching of low currents, whereby voltage peaks occur as a result of the inductivity effect and may result in breakthroughs. To minimize the chopping effect, a small amount of a metal with high vapor pressure is added to the contact material, which reduces the constriction of the are caused by current forces. Bonded materials with a high melting metal skeleton structure, such as tungsten, molybdenum or rhenium are usable up to a limit, as contact materials in vacuum power switches. Due to the high atom weight of these materials, the electrical voltage stability of the switch, based on the diffusion of metal vapor out of the contact gap, is not restored quickly enought. The switching currents are limited to about 4 kA. Metals having an atomic weight 65, as for example, copper,iron, cobalt,

nickel and beryllium, may be considered for use as original metals that yield an action supplement of high vapor pressure, as an antichopping component. Thus, it is known to use copper contact pieces, which are provided with recesses whereinto the copper bismuth rings are inserted. Alloys with the original metal copper and the antichopping supplement, such as, e.g., bismuth, makes it difficult, at the required low gas content, to distribute the bismuth uniformly and in a defined manner, in the contact layer of the copper. Moreover, when a homogenous copper bismuth alloy is used, it is hard to produce a firm connection, which is resistant to temperature changes, between the contact piece and the carrier metal, since the active component, e.g., bismuth, leads to a considerable brittleness of the contact material and the solder layer and to a reduction of the stability.

The object of the present invention is to overcome heretofore encountered difficulties during the production of two layer contact pieces.

To this end and in accordance with the invention, an auxiliary metal and a diffusion metal is alloyed, through diffusion, into a surface of a metallic original body of high electrical conductivity, whereby the auxiliary metal forms a molten phase with the diffusion metal and the metallic original body.

In carrying out the method, the auxiliary metal and the diffusion metal are brought into contact with a surface of the metallic body as an alloy or a power mixture of specified composition, as a loose powder or a pulverulent pressedmass. The alloy, the powder mixture or the pulverulent pressed mass are subsequently alloyed into the metallic original body by means of diffusion, so that the amount of the auxiliary metal provides a defined diffusion depth in the original body at predetermined diffusion conditions.

It is possible to use copper, nickel, iron, cobalt or beryllium, as the original body, and bismuth, lead, tellurium or antimony, for example, as the diffusion metal.

It is preferred to use such metals, as auxiliary metals, which form a liquid phase with said metallic original body and with the diffusion metal, at least 50C below the melting temperature of the metallic original body.

The use of an auxiliary metal offers the advantage that a diffusion temperature may be used which is considerably below the melting temperature of the metallic original body. When the original body consists of copper, the auxiliary metal of silver and the diffusion metal of bismuth, a diffusion temperature between 800 and 1,000 C is suitable in order to obtain, within a period of 10 to 30 minutes, a state of equilibrium and to produce thereby the desired diffusion layer. When pure bismuth is used as a diffusion metal, and copper is employed as the original body, a desired equilibrium Bi content of 2% would result at a diffusion temperature of 1,075 C, without the use of an auxiliary metal. Since this temperature is only 8 C below the melting temperature of the copper, it is virtually impossible to comply with the required temperature in a furnace for the pur pose of manufacture.

The invention will be shown in greater detail with reference to the Drawing, in which there is shown in FIGS. 1 to 5, the steps of carrying out the invention.

A wafer-shaped contact specimen (original body) 11 of mm diameter and a height of 20 mm, is cast from a highly degassed copper, is illustrated in FIG. I.

In FIG. 2, an annular recess 12 with dimensions (1),, 40 mm, (b, 30 mm, depth 5 mm, and corresponds approximately to the future contact area, is provided in a surface of the original body. A pressed mass of powder 13 (FIG. 3) comprising a mixture of 10 g silver, 15 g copper and l g bismuth, and adjusted to a diffusion temperature of l,000 C is inserted into the recess 12. This produces a liquid phase, forming an equilibrium of 10 g silver and approximately 40 g copper, which contains a uniform distribution of the bismuth. The liquid phase which corresponds to the diffusion range 14, is shown in FIG. 4. After the diffusion is completed, the contact piece which consists of the carrier layer 1 1 and the indiffused contact area I5, is produced as shown in FIG. 5. The diffusion zone boundary of the contact area 15 is illustrated by the dashed lines. The contact piece, thus obtained, may be easily connected by eutectic means with the carrier metal copper, through customary solders such as for example, AgCu.

When iron, nickel, cobalt or beryllium are used for the original body, appropriate auxiliary metals are to be selected which form at diffusion temperature a liquid phase with the metal of the original body that melts at lower temperatures than the metal of the original body. The liquid phase produces, in the form of mixed crys tals, an eutectic or peritectic, depending on the solubility rate, and the amount of auxiliary metal and diffusion metal is determined for a desired depth of penetration.

When using Cu as the original metal, the auxiliary metal may be selected from Ag, Cd, Ge, In, Mg, Si, Sn, Zn, Ce and the diffusion metal may be selected from Te, Bi, Pb, and Sb.

When using Fe as the original metal the auxiliary metal may be selected from Cu, Be, Ce, Fe+(l4.5) wt-% C, Ge, Nb, Sb, Si, Ti and the diffusion metal may be selected from Te, Bi and Pb.

When using Co as the original metal the auxiliary metal may be selected from B, Co+Il-3) wt-% C, Ge, Nb, Sb, Si, Sn, Ti and the diffusion metal may be selected from Te, Bi and Pb.

When using Ni as the original metal, the auxiliary metal may be selected from B, Be, Ni+( l2.5) wt-% C,

Ce, Mg, Nb, Sb, Si, Sn and the diffusion metal may be selected from Te, Bi or Pb.

When using Be as the original metal, the auxiliary metal may be selected from Ag, Cu, Si and the diffusion metal may be selected from Te, Bi or Pb.

I claim:

1. A process for preparing a two layer contact piece for high vacuum power switches which comprises alloying a diffusion metal and an auxiliary metal into a surface of a metallic original body of high electrical conductivity, thereby forming a molten phase with the diffusion metal and the metallic original body, said auxiliary metal being a metal which forms a liquid phase with the metallic original body and with the diffusion metal at a temperature at least 50 C below the melting point of the metallic original body.

2. The process of claim 1, wherein the diffusion metal and the auxiliary metal are together brought into contact with the surface of the metallic original body and then diffused into the original body, the amount of the auxiliary metal providing a defined diffusion depth in the original body at the diffusion conditions.

3. The process of claim 2, wherein a body constituting the diffusion metal and the auxiliary metal are brought into an annular recess in the surface of the original body.

4. The process of claim 3, wherein a metal selected from copper, nickel, iron, cobalt and beryllium, is used as the original body.

5. The process of claim 3, wherein a metal selected from bismuth, lead, tellurim and antimony, is used as the diffusion metal.

6. The process of claim 3, wherein a metal selected from copper, nickel, iron, cobalt and beryllium is used as the original body, a metal selected from bismuth, lead, tellurim and antimony is used as the diffusion metal, a metal which forms a liquid phase with the metallic original body and with the diffusion metal at a temperature at least 50 C below the melting point of the original metal, is used as the auxiliary metal.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2049771 *Feb 6, 1935Aug 4, 1936Mallory & Co Inc P RMethod of making silver contacts
US2379232 *Nov 2, 1943Jun 26, 1945Mallory & Co Inc P RMetallic compositions containing bismuth
US3008022 *Jun 15, 1960Nov 7, 1961Gen ElectricContact structure for a vacuum-type circuit interrupter
US3502465 *May 24, 1967Mar 24, 1970Mitsubishi Electric CorpContact alloys for vacuum circuit interrupters
US3596027 *Jul 24, 1969Jul 27, 1971Tokyo Shibaura Electric CoVacuum circuit breaker contacts consisting essentially of a copper matrix and solid solution particles of copper-tellurium and copper-selenium
US3610859 *Jul 29, 1968Oct 5, 1971Siemens AgComposite contact structure for vacuum-type circuit interrupters
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3845543 *Feb 22, 1973Nov 5, 1974Sprecher & Schuh AgMethod of producing a vacuum switch contact
US4129760 *May 27, 1977Dec 12, 1978Tokyo Shibaura Electric Co., Ltd.Aluminum-beryllium containing alloy
US4129761 *May 27, 1977Dec 12, 1978Tokyo Shibaura Electric Co., Ltd.Vacuum circuit breaker
US4530815 *Jun 27, 1983Jul 23, 1985Mitsubishi Denki Kabushiki KaishaSintering to solidify powdered alloy contact material
US4760223 *Oct 14, 1987Jul 26, 1988Kabushiki Kaisha ToshibaVacuum circuit interrupter
US5254185 *Dec 17, 1990Oct 19, 1993Calor-Emag AgPreheating substrate, applying powder additive; wetting
US5334809 *Feb 11, 1993Aug 2, 1994Particle Interconnect, Inc.Particle enhanced joining of metal surfaces
US5653827 *Jun 6, 1995Aug 5, 1997Starline Mfg. Co., Inc.Brass alloys
US5726407 *Mar 7, 1996Mar 10, 1998Kabushiki Kaisha ToshibaContact electrode for vacuum interrupter
US5741377 *Apr 10, 1995Apr 21, 1998Martin Marietta Energy Systems, Inc.Preparing biaxially textured metal alloy article; superconductors
US5835359 *Nov 6, 1996Nov 10, 1998Particle Interconnect CorporationApparatus for coupling power transmission mediums to a contact point
US5898020 *May 22, 1996Apr 27, 1999Goyal; AmitStructures having enhanced biaxial texture and method of fabricating same
US5958599 *Jan 9, 1998Sep 28, 1999Lockheed Martin Energy Research CorporationStructures having enhanced biaxial texture
US5964966 *Sep 19, 1997Oct 12, 1999Lockheed Martin Energy Research CorporationFormed by rolling and annealing a nickel alloy containing specific amounts of a group 5b element, group 6b element, tin, aluminum, copper, zinc and titanium; low curie point, enhanced mechanical properties; superconductor applications
US6022832 *Jan 15, 1998Feb 8, 2000American Superconductor CorporationLow vacuum vapor process for producing superconductor articles with epitaxial layers
US6027564 *Jan 15, 1998Feb 22, 2000American Superconductor CorporationPlacing a crystallographically oriented target surface of a substrate, including contaminant materials in high pressure and heating the substrate surface to greater than the threshold temperature for forming epitaxial layer
US6106615 *Feb 16, 1999Aug 22, 2000Goyal; AmitMethod of forming biaxially textured alloy substrates and devices thereon
US6114287 *Sep 30, 1998Sep 5, 2000Ut-Battelle, LlcOvercoating with ductile buffer; deforming
US6296701Sep 30, 1998Oct 2, 2001Ut-Battelle, LlcMethod of depositing an electrically conductive oxide film on a textured metallic substrate and articles formed therefrom
US6426320Dec 29, 1999Jul 30, 2002American Superconductors CorporationControlling velocity
US6428635Oct 1, 1997Aug 6, 2002American Superconductor CorporationSubstrates for superconductors
US6458223Mar 31, 1999Oct 1, 2002American Superconductor CorporationAlloy materials
US6475311Mar 31, 1999Nov 5, 2002American Superconductor CorporationAlloy materials
US6555256Nov 6, 2000Apr 29, 2003Ut-Battelle, LlcElectroconductive buffer layer epitaxially deposited on a polycrystalline biaxially textured substrate
CN1065068C *Mar 11, 1996Apr 25, 2001东芝株式会社Contact electrode for vacuum interrupter
DE19809306A1 *Mar 5, 1998Sep 9, 1999Abb Patent GmbhKontaktstück für eine Vakuumkammer und Verfahren zur Herstellung des Kontaktstückes
WO1996032201A1 *Apr 10, 1996Oct 17, 1996Lockheed Martin Energy Sys IncStructures having enhanced biaxial texture and method of fabricating same
Classifications
U.S. Classification427/191, 420/497, 420/590, 148/512, 218/132, 419/5, 218/130, 200/266
International ClassificationH01H1/02
Cooperative ClassificationH01H1/0203
European ClassificationH01H1/02D