US3880777A - Composite electrical contact material comprising Ag and intermetallic compounds - Google Patents

Composite electrical contact material comprising Ag and intermetallic compounds Download PDF

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Publication number
US3880777A
US3880777A US320888A US32088873A US3880777A US 3880777 A US3880777 A US 3880777A US 320888 A US320888 A US 320888A US 32088873 A US32088873 A US 32088873A US 3880777 A US3880777 A US 3880777A
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Prior art keywords
contact material
silver
electrical contact
composite electrical
alloy
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US320888A
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English (en)
Inventor
Akira Shibata
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Chugai Electric Industrial Co Ltd
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Chugai Electric Industrial Co Ltd
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    • 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
    • H01H1/0237—Composite material having a noble metal as the basic material and containing oxides
    • H01H1/02372—Composite material having a noble metal as the basic material and containing oxides containing as major components one or more oxides of the following elements only: Cd, Sn, Zn, In, Bi, Sb or Te
    • 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

Definitions

  • ABSTRACT Process for the preparation of a composite electrical contact material consisting of an alloy composed of 84 to 90 weight percent of silver, 1.0 to 4.0 weight percent of the components consisting of at least two of zinc, tin or antimony, and less than 0.5 weight percent of the intermetallic compound of one of the group 2A elements of the Periodic Table with nickel or cobalt. the balance being cadmium, said alloy being formed into a strip or contact form and subjected to an internal oxidation at a temperature of 700 to 750C.
  • SHEET 2 [IF 2 COMPOSITE ELECTRICAL CONTACT MATERIAL COMPRISING AG AND INTERMETALLIC COMPOUNDS This invention relates to a composite electric contact material and method of preparing the same.
  • Electrical contact material of the silver/cadmium oxide alloy has a superior physical property in point of anti-weld characteristic. low contact resistance and long service life.
  • the compound alloy material obtained by internal oxidation is advantageous economically and has an excellent property compared to that obtained by powder metallurgical methods.
  • the property of the contact material obtained by internal oxidation depends considerably on the kind and property of the oxides precipitated by internal oxidation, and the shape and capacity ofprecipitation particles.
  • the nonfusibility and current breaking performance of the contact material are governed markedly by the volume and refractory characteristics of the oxides. It was recently realized that the refractoriness and anti-weld characteristic of the silver alloy. mixed and melted with tin, zinc or antimony to provide non-fusible oxide. could be improved through oxidation. Addition of nickel and cobalt in a trace amount to the silver alloy is effective to prevent coarse particles of precipitated oxides from forming in the course of internal oxidation.
  • This invention aims, therefore, at the provision of electrical contact material capable of retaining its structure and high strength up to a higher temperature and withstanding larger electrical impulse through the combination of the strengthened grain boundaries of polycrystalline structure and local strains produced in the matrix.
  • this invention provides a process for the preparation of a composite electrical contact material consisting of an alloy composed of 84 to 90 weight percent of silver. 1.0 to 4.0 weight percent of the components consisting of at least two of zinc. tin, or antimony. and less than 0.5 weight percent of the intermetallic compound of one of the group 2A elements of the Periodic Table with nickel or cobalt. the balance being cadmium, said alloy being formed into a desired configuration and subjected to an internal oxidation at a temperature of 700 to 750C.
  • FIG. 1 is a photomicrograph at a magnification of 200 X of a cross section of a contact of the cadmium oxide-silver type in accordance with the present invention.
  • FIG. 2 is a photomicrograph at a magnification of 200 X of a cross section of a contact of the cadmium oxide-silver type made in accordance with a conventional internal oxidation,
  • FIG. 3 is an enlarged explanatory view of the contact obtained in accordance with the present invention, in which the letter P indicates minute particles and the letter 1 the width of crystalline silver grain,
  • FIG. 4 is a photomicrograph similar to FIG. 1, in which the internal oxidation of the alloy was made at a temperature below 700C, and
  • FIG. 5 is a photomicrograph similar to FIG. 4, in which its internal oxidation was conducted at a temperature above 750C.
  • Elements belonging to group 2A of the Periodic Table have the property of comminuting the crystals of the metallic alloy. while nickel and cobalt have the property of retarding the growth of precipitated particles and hence lowering the velocity of diffusion thus contributing to the formation of minute precipitated particles. It has been found out that addition of less than 0.5 percent in weight of the intermetallic compound of Be, Mg or Ca with Ni or C0 leads to the retarded growth of the silver crystalline grains and to the precipitation of the oxides in the grain boundaries, thus preventing the diffusion of the internal solute metal into the grain boundaries and the macroscopic difference in concentration of the oxides in the outer and inner zones. It was also found that addition of such compound in higher than 0.5 weight percent lead to embrittled alloy material and segregation in its structure.
  • Minute particles (P in FIG. 3) of the convenient size of l to 3 ,u are precipitated in the grains (of the size I in FIG. 3).
  • Precipitation of too fine particles leads to marked decrease in the silver volume and aggravated conductivity and generation of excessive heat. thus leading to worsened current breaking characteristics.
  • the temperature of internal oxidation in the range of 700 to 750C is convenient for the reason that the precipitated oxide particles otherwise will become so fine that they can not be observed under the microscope, causing temperature increase and aggravated nonfusibility and resistance to consumption of the contact material, at a temperature below 700C (See FIG. 4), while the growth of silver crystal grains will be enhanced at a temperature higher than 750C thus promoting the diffusion of solute metal into the grain boundaries and self-diffusion of silver. but will result in enhanced silver concentration in the silver crystal grain boundaries, but extinction of oxide walls at boundaries and larger difference of oxides at the surface and inner zones (See FIG. 5).
  • Sublimation of CdO occurs at 760C, while the sublimation temperatures or melting points of ZnO, SnO and SbO are varied. It is therefore evident that contact material consisting of silver/cadmium oxide and only one of ZnO, SnO' and SbO has its nonfusibility lowered for a certain intermediate current range. On the other hand. the contact material of the present invention has an improved resistivity to such temperature range and has an excellent characteristic as contact material for a current breaker which has to be frequently opened or closed.
  • the composition of the present invention compound material is selected so as to correspond to the required refractoriness and also to be convenient for formation of the intermetallic compound.
  • SnO or SbO is added in view of the evaporation characteristics of such oxides in the higher temperature range and resultant nonfusibility and refractoriness of such oxides at higher temperatures. Where current interruption characteristics is required exclusively. SnO and SbO are used as these constitutents. For high-voltage conductors, SbO is employed in addition to ZnO and SnO, because SbO readily forms an intermetallic compound with SnO and ZnO. Other applications can also be considered within the scope of the present invention.
  • Comparative test samples 5, 6, 7, and 8 were prepared as shown below.
  • the samples were further tested for refractoriness by measuring the following values.
  • Item A The decrease in the outside diameters as observed when the samples were maintained at 1,000C for 10 minutes in the atmosphere.
  • Item B The weight change as observed when the samples were used as contacts in a circuit (200V, 5,000A), the circuit being closed and opened 10 times.
  • Item l The times of 200V-10000A, 10 times.
  • a composite electrical contact material as claimed in claim 1 which has a polycrystalline structure comprising crystalline silver grains provided with grain boundaries of highly concentrated hard oxides and contained by refractory compound oxide particles precipitated in the grains.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Contacts (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Manufacture Of Switches (AREA)
  • Conductive Materials (AREA)
US320888A 1972-02-15 1973-01-04 Composite electrical contact material comprising Ag and intermetallic compounds Expired - Lifetime US3880777A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47015453A JPS4883392A (enrdf_load_stackoverflow) 1972-02-15 1972-02-15

Publications (1)

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US3880777A true US3880777A (en) 1975-04-29

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JP (1) JPS4883392A (enrdf_load_stackoverflow)
DE (1) DE2303050C3 (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4115325A (en) * 1977-05-31 1978-09-19 Texas Instruments Incorporated Electrical contact material
US4168519A (en) * 1976-09-23 1979-09-18 Erie Technological Products Inc. Capacitor with tin-zinc electrodes
US4479892A (en) * 1983-05-16 1984-10-30 Chugai Denki Kogyo K.K. Ag-Metal oxides electrical contact materials
DE3728328A1 (de) * 1986-08-26 1988-03-10 Matsushita Electric Works Ltd Kontaktmaterial und verfahren zu seiner herstellung
DE3810218A1 (de) * 1987-03-25 1988-10-06 Matsushita Electric Works Ltd Leitfaehiges verbundmaterial und verfahren zu seiner herstellung

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55134146A (en) * 1979-04-04 1980-10-18 Tokuriki Honten Co Ltd Silver-cadmium oxide type electrical contact material
JPS56130094A (en) * 1980-03-17 1981-10-12 Tanaka Precious Metal Ind Rectifier or brush material
JPS58107445A (ja) * 1981-12-18 1983-06-27 Tanaka Kikinzoku Kogyo Kk 摺動接点材料
DD218806A3 (de) * 1982-11-15 1985-02-13 Funk A Bergbau Huettenkombinat Abbrandfestes schaltstueck

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1257654A (enrdf_load_stackoverflow) * 1969-04-11 1971-12-22

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2007490A1 (en) * 1968-04-22 1970-01-09 Mallory & Co Inc P R Electrical contact of cdo/ag with integrally bonded layer - of ag or other metal
JPS5413405B1 (enrdf_load_stackoverflow) * 1969-03-20 1979-05-30
DE2011002C3 (de) * 1970-03-09 1978-10-05 Fa. Dr. Eugen Duerrwaechter Doduco, 7530 Pforzheim Schmelzmetallurgisch hergestellter innenoxidierter Kontaktwerkstoff auf Silber-Kadmiumoxid-Basis

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1257654A (enrdf_load_stackoverflow) * 1969-04-11 1971-12-22

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Hara et al., Silver and Base Metal Alloy Contact Materials, in Proc. Holm. Sem. on Elec. Contact. Phenomena. (1969). *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4168519A (en) * 1976-09-23 1979-09-18 Erie Technological Products Inc. Capacitor with tin-zinc electrodes
US4115325A (en) * 1977-05-31 1978-09-19 Texas Instruments Incorporated Electrical contact material
US4479892A (en) * 1983-05-16 1984-10-30 Chugai Denki Kogyo K.K. Ag-Metal oxides electrical contact materials
DE3728328A1 (de) * 1986-08-26 1988-03-10 Matsushita Electric Works Ltd Kontaktmaterial und verfahren zu seiner herstellung
DE3810218A1 (de) * 1987-03-25 1988-10-06 Matsushita Electric Works Ltd Leitfaehiges verbundmaterial und verfahren zu seiner herstellung
US5022932A (en) * 1987-03-25 1991-06-11 Matsushita Electric Works, Ltd. Rapid solidification of metal-metal composites having Ag, Au or Cu atrix

Also Published As

Publication number Publication date
DE2303050C3 (de) 1980-01-17
DE2303050A1 (de) 1973-08-23
DE2303050B2 (de) 1978-04-06
JPS4883392A (enrdf_load_stackoverflow) 1973-11-07

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