US2789187A - Electrical contact devices, particularly for high switching frequency and high current loading - Google Patents

Electrical contact devices, particularly for high switching frequency and high current loading Download PDF

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Publication number
US2789187A
US2789187A US470060A US47006054A US2789187A US 2789187 A US2789187 A US 2789187A US 470060 A US470060 A US 470060A US 47006054 A US47006054 A US 47006054A US 2789187 A US2789187 A US 2789187A
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United States
Prior art keywords
contact
surface layer
current loading
switching frequency
electrical contact
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US470060A
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English (en)
Inventor
Romer Otto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens and Halske AG
Siemens Corp
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Siemens Corp
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Filing date
Publication date
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/20—Contact mechanisms of dynamic converters
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C5/00—Alloys based on noble metals
    • C22C5/02—Alloys based on gold
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C5/00—Alloys based on noble metals
    • C22C5/04—Alloys based on a platinum group metal
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/021—Composite material
    • H01H1/023—Composite material having a noble metal as the basic material

Definitions

  • the material preferably used as contact material in such devices is silver, because this metal has a very low contact resistance.
  • silver when operating at extremely high switching frequencies, the use of silver results in excessive migration and evaporation of material as well as in excessive frictional wear.
  • the frictional wear caused by the mechanical impacts of the contact closing operations increases the contact resistance, and this results in heating the contacts to a high temperature so that they become damaged or destroyed after unsatisfactory short periods of use.
  • the known silver alloys for control purposes also have excessive electrical wear when used at high switching frequencies and are generally inferior ,because of their high specific electrical resistance.
  • a contact piece consisting of a carrier or terminal body of good conducting material such as copper, silver and/oigold, and a surface layer joined with the carrier body and forming the active contact face of the piece; and I form the surface layer of a sintered composition comprising about 20% to about 70% gold, and 80% to 30% of high-melting noble metal selected from iridium and rhodium.
  • FIG. 16 1957 An example of a switching device equipped with contact pieces according to the invention is schematically Patented Apr. 16, 1957 illustrated in the accompanying drawing representing a partly sectional view.
  • the illustrated device has two stationary contact pieces each having a relatively large carrier body 1, 2 of copper, silver or gold and a surface layer 10, 20 intimately joined with the carrier body by soldering, brazing or welding.
  • the contact pieces are mounted on an insulating support 3.
  • the two stationary pieces are periodically interconnected by a movable contact piece also composed of a carrier body 4, for instance of silver, and a surface layer 40 intimately joined with the body 4 in the afore-described manner.
  • the movable contact piece is urged by a spring 5 toward bridging engagement with the stationary contact pieces and is actuated in opposition to the spring 5 by an axially displaceable tappet 6 controlled by a cam 7 on a continuously revolving shaft 8.
  • the shaft 8 revolves at the frequency of the alternating current to be rectified.
  • the electric contact is made and broken between the surface layer 40 and the surface layers 10 and 20 and, as mentioned, these surface layers are composed of a sintered alloy or agglomeration of the highconductance metal, namely gold, with the high-melting noble metal namely indium and/ or rhodium.
  • composition namely the gold and the noble metal, form together the bulk or substantially all of the composition, that is these two constituents together amount preferably to more than 70% of the entire composition.
  • the composition may also comprise a balance of other base metals and/or small amounts of paladin-m or platinum.
  • the corrosion resistant high melting noble metals iridium and rhodium have a relatively small specific electric resistance. These two high-melting noble metals, moreover, are highly resistant to electrically caused attacks as well as to mechanical wear. In combination with gold, the relatively high electrical conductance of or burning away of the materials are still further improved by the good electrical and thermal conductance of the.
  • the contact devices according to the invention are particularly useful in high frequency switching operations at higher Current and power loads than similar devices comprising known contact materials. Compared with the known contact materials, the compositions used according to the invention result in a much longer period of useful life of the contact devices and permit operation of the devices at higher switching frequencies.
  • the compositions for the surface layers according to the invention are of the sintered type. That is, the compositions are produced by powder metallurgl- One way of production is to mix the components in pulverulent form, to compress and mold the mixture and then to fuse and solidify it by subjecting the molded body to sintering temperature. Another way of. producing the composition is to first produce a sintered porous body or skeleton structure of the high-melting noble metal, then. placing the proper quantity of gold onto the molded body, and thereafter heating the body in vacuum to a temperature above the melting point of the high-conductance metal or metals so that thelatter metals penetrate into and form an alloy with the sintered skeleton structure of the high-melting noble metals.
  • the surface layer of the contact piece is to have a particularly high density or hardness
  • one or more metals that form hard alloys with gold may be added to the com-
  • Such additive'metals are, for instance, pal ladium and platinum.
  • the amount of such additions is preferably about 1% up to 20%.
  • the mechanical or frictional wear can be reduced by heating to the contact composition a slight amount of metal selected from indium, tin, cadmium or zinc in accordance with.
  • metal selected from indium, tin, cadmium or zinc in accordance with.
  • indium, but tin, lead, cadmium or Zinc can be used instead or in combination with indium.
  • Preferred limits for additional indium are about 1% to 9%, for cadmium about 3% to for tin or lead about 10% and for zinc about The total amount of such additions should not exceed about 20%.
  • the added quantity of iridium, tin lead, cadmium or zinc is placed upon the contact face of. the surface layer and the contact piece is then. ternpered in order to cause the metal to diffuse into the surface layer. In this manner, the surface layer is converted into a superficial zone in which the above-described composition of high-conductance metal and noble metal forms an alloy with the indiumor other metal used.
  • the above-mentioned metals of the indium group may also be mixed with the constituents of the composition before sintering the composition, or they can be electroplated onto the contact face of the surface layer, preferably with a subsequent heating treatment for the production of a diffusion zone.
  • a contact piece of low electric resistance, particularly for frequent switching operation comprising a carrier 'body' of good conductr ing material and a surface layer joined with said body to provide a contact face for switching operation, said surface layer being formed.
  • a sintered composition comprising about 20% to about of gold, and 80% to 30% of metal selected from the group consisting of iridium and rhodium.
  • a contact piece of low electric resistance, particularly for frequent switching operation under heavy current loading comprising a carrier body of good conducting material and a surface layer joined with said body to provide a contact face for switching operation, said surface layer being formed ofa sintered composition having a skeleton structure of about 30% to about 80% of metal selected from the group consisting of iridium and rhodium, and 70% to 20% of gold interspersed in" and alloyed with said structure.
  • a contact pieceof low electric resistance, particularly for frequent switching operation under heavy current loading comprising a carrier body of good conducting material and a surface layer. joined with. said. body to provide a contact face for switching operation, said larly for frequent switching operation under heavy cur-- rent loading, comprising a carrier body of 7 good conduct-.
  • a sintered composition comprising about 20% to about 70% gold, and 3.0% to 80% of constituent substance selected from the group consisting of iridium and rhodium, and a remainder con sisting essentially of about 1% to about 20% of metal selected from the' group consisting of indium, tin, lead, cadmium and zinc.
  • a contact piece of low electric resistance, particularly for frequent switching operation under heavy current loading comprising a carrier body of good conduct: ing material and a surface layer joined with said body to provide a contact face for switching operation, said surface layer being formed of a sintered compositioncomprising about 20% to about 70% of gold, 30% to 80% of substance selected from the group consisting of provide a contact. face for switching operation, saidsurface layer being formed of. a sintered composition comprising 20% to 65% of gold, 5% to 30% of nickel, the. remainder consisting essentially of 30% to of metal elected from the group consisting of iridium and. rhodium.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Composite Materials (AREA)
  • Power Engineering (AREA)
  • Contacts (AREA)
US470060A 1953-12-03 1954-11-19 Electrical contact devices, particularly for high switching frequency and high current loading Expired - Lifetime US2789187A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES36602A DE1134520B (de) 1953-12-03 1953-12-03 Verwendung von auf pulvermetallurgischem Wege hergestellten Legierungen auf Gold-, Iridium- oder Rhodium-Basis als Werkstoff fuer die kontaktgebenden Teile elektrischer Kontakte

Publications (1)

Publication Number Publication Date
US2789187A true US2789187A (en) 1957-04-16

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US470060A Expired - Lifetime US2789187A (en) 1953-12-03 1954-11-19 Electrical contact devices, particularly for high switching frequency and high current loading

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US (1) US2789187A (de)
DE (1) DE1134520B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3015587A (en) * 1958-09-05 1962-01-02 Technology Instr Corp Of Acton Rhodium germanium film resistor
US3049604A (en) * 1958-07-18 1962-08-14 Jr Edward W Showalter Commutator and method of making same
US3219890A (en) * 1959-02-25 1965-11-23 Transitron Electronic Corp Semiconductor barrier-layer device and terminal structure thereon
US3440062A (en) * 1966-02-28 1969-04-22 Du Pont Metalizing compositions containing critical proportions of metal (pt-au or pd-au) and a specific high density frit
US3876560A (en) * 1972-05-15 1975-04-08 Engelhard Min & Chem Thick film resistor material of ruthenium or iridium, gold or platinum and rhodium

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4062676A (en) * 1976-07-06 1977-12-13 Deutsche Gold- Und Silber-Scheideanstalt Vormals Roessler Gold alloy for firing on porcelain for dental purposes

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1990277A (en) * 1930-09-13 1935-02-05 Feussner Otto Metals of the platinum group and certain alloys
US2048648A (en) * 1932-07-13 1936-07-21 Feussner Otto Alloy and process for making same
US2241262A (en) * 1939-10-26 1941-05-06 Baker & Co Inc Electrical contact
US2417967A (en) * 1944-02-23 1947-03-25 Mallory & Co Inc P R Contact element

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE611709C (de) * 1932-02-02 1935-04-03 Heraeus Gmbh W C Edelmetallformstuecke hoher Haerte
DE708166C (de) * 1937-11-25 1941-07-14 Siebert G M B H G Verwendung von Silberlegierungen fuer Gegenstaende erhoehter Widerstandsfaehigkeit gegen thermische und mechanische Beanspruchung
DE707861C (de) * 1939-10-04 1941-07-05 Heraeus Gmbh W C Elektrischer Kontakt
DE727512C (de) * 1939-11-30 1942-11-05 Heraeus Gmbh W C Elektrischer Kontakt
DE747830C (de) * 1941-06-17 1945-01-20 Verwendung von Goldlegierungen fuer elektrische Kontakte

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1990277A (en) * 1930-09-13 1935-02-05 Feussner Otto Metals of the platinum group and certain alloys
US2048648A (en) * 1932-07-13 1936-07-21 Feussner Otto Alloy and process for making same
US2241262A (en) * 1939-10-26 1941-05-06 Baker & Co Inc Electrical contact
US2417967A (en) * 1944-02-23 1947-03-25 Mallory & Co Inc P R Contact element

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3049604A (en) * 1958-07-18 1962-08-14 Jr Edward W Showalter Commutator and method of making same
US3015587A (en) * 1958-09-05 1962-01-02 Technology Instr Corp Of Acton Rhodium germanium film resistor
US3219890A (en) * 1959-02-25 1965-11-23 Transitron Electronic Corp Semiconductor barrier-layer device and terminal structure thereon
US3440062A (en) * 1966-02-28 1969-04-22 Du Pont Metalizing compositions containing critical proportions of metal (pt-au or pd-au) and a specific high density frit
US3876560A (en) * 1972-05-15 1975-04-08 Engelhard Min & Chem Thick film resistor material of ruthenium or iridium, gold or platinum and rhodium

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Publication number Publication date
DE1134520B (de) 1962-08-09

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