Classifications

• • 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
  • H01H1/02376—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 containing as major component SnO2
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/10—Alloys containing non-metals
  • C22C1/1078—Alloys containing non-metals by internal oxidation of material in solid state
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
  • C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
  • C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
  • C22C32/0021—Matrix based on noble metals, Cu or alloys thereof

Definitions

• This invention relates to electrical contact materials which are used for electrical contacts employed in electrical apparatuses such as switches, breakers, contactors, and the like.
• Electrical contact materials dealt with in this invention are particularly those made of Ag-Sn alloys which are made by melting Ag and Sn and which are internally oxidized. Those belong to a different category from those which are prepared by mixing Ag and SnO powders and powdermetallurgically sintering them.
• Ag-Sn oxides alloys in which Ag is a matrix and Sn, solute metal thereof is internal-oxidized to Sn oxides are widely used as electrical contact materials for the electrical apparatuses of the kind mentioned above.
• auxiliary solute metals which have higher diffusion velocities or which are more capable to carry oxygen and to convey the oxygen more efficiently into deeper inner areas of Ag matrices.
• Such auxiliary solute metals are typically In and Bi.
• this invention is to provide entirely novel electrical contact materials which are prepared by melting, are consisted of 5-20 weight % of Sn and balance of Ag, only, and are internal-oxidized.
• a Sn amount in this invention its minimum is 5 weight % in order to afford the obtained electrical contact materials with efficient refractoriness, and its maximum is 20 weight %, because if Sn is given in an amount more than 20 weight %, the resultant materials will be too brittle.
• one or more elements selected form iron family elements Fe, Co, and Ni
• iron family elements may be added to said secondary Ag alloys. Such addition is not for the acceleration or assistance of internal-oxidation, but merely for fining or minuting alloy crystalline structures of the resultant alloys. In order to achieve this end, iron family elements will be added at an amount of 0.001-1 weight %.
• This invention is also to provide a novel method for preparing the above-mentioned novel electrical contact materials.
• the heating temperature when the oxygen atmosphere pressure is made comparatively low above 10 atm, the heating temperature will preferably be made high within the above-mentioned range of about 500-750°C. And, on the contrary, it is preferable that when the oxygen atmosphere is comparatively high above 10 atm, the heating temperature will be made low within the above-mentioned range of internal-oxidation heating temperature.
• the heating temperature when the heating temperature is sided low within the above-mentioned range of temperature or near to its minimum temperature of about 500°C, it is better to make the oxygen atmosphere as much as higher.
• the maximum oxygen atmosphere preferably employable in this invention will be up to about 200 atm.
• the lower and upper or minimum and maximum oxygen atmosphere shall preferably be 10 atm and 200 atm, and its heating temperature shall preferably be in a range of about 750°C to about 500 °C.
• the above constituents (1) and (2) were melted and made to ingots of 120mm in diameter and 40mm in length.
• the ingots were hot-extruded into squre bars of 30mm in thickness and 50mm in width.
• the bars were then cut to a length of 500mm each, and their upper and lower surfaces were shaved by a thickness of 3mm each to obtain square bars of 24mm in thickness, 510mm in width, and 500mm in length.
• the disk-shaped contacts were internal-oxidized by heating then to 620°C for 24 hours at a normal oxygen atmosphere of 1 atm.
• the resultant contacts (3) were observed by a microscope, similarly to the contacts (1) and (2). It was found that Sn was completely internal-oxidized in this contacts too, while they were precipitated squamously along Ag grain boundaries, and were noticeably coarse than those of the contacts (1) and (2).
• HRP Hardness
• IACS electrical conductivity
• Amounts of consumption (mg) by ASTM test method were as follows.
• this invention can provide absolutely novel electrical contact materials made of Ag-Sn (5-20 weight %) alloys which has been prepared by melting and internal-oxidized.
• the electrical contact materials made in accordance with this invention are substantially secondary Ag-Sn alloy provided with Sn oxides precipitated extremely finely and evenly in its Ag matrix and, consequently having excellent contact properties including their improved electrical conductivities.

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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)
• Contacts (AREA)
• Manufacture Of Switches (AREA)

Priority Applications (1)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8205287

Family Applications (1)

Country Status (1)

Citations (3)

• 1990
  • 1990-02-09 EP EP90301383A patent/EP0441018A1/fr not_active Withdrawn

Patent Citations (3)

Non-Patent Citations (1)

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