Electricity: conductors and insulators – Conduits – cables or conductors – Conductor structure
Reexamination Certificate
2001-04-16
2003-11-18
Mayo, III, William H. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Conductor structure
C174S126200, C174S128200
Reexamination Certificate
active
06649843
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composite conductor, production method thereof and a cable using the same conductor, and more particularly to a composite conductor used for a core wire or inner conductor (simply defined as “core” hereinafter) of a small-diameter coaxial cable and/or an external or outer conductor (simply defined as “external conductor” hereinafter) and a production method thereof.
2. Description of the Related Art
The small-diameter coaxial cable equal to or less than 36 AWG (7-stranded wires) in conductor size is used for medical probe cable, an insertion cable in catheter, LCD harness cable and the like. Conventionally, a stranded conductor of Cu or Cu alloy of 50 &mgr;m or less in diameter has been used.
In recent years, demand for multiple cores in case of medical probe cable, demand for reduction of the cable diameter in case of catheter insertion cable and demand for use of a single core in case of the LCD harness cable have been increased. That is, in these cables, cable material having a smaller diameter, excellent strength and flexing characteristic is demanded. Considering reduction of the diameter and economic performance, as the core, the single-wire cable is more favorable than the stranded cable. Therefore, instead of the stranded cable composed of the conventional core of Cu alloy having a short service life against flexings and insufficient strength and conductivity, the single-wire cable composed of alloy material (alloy cable material) having excellent strength and flexing resistance has been demanded.
As the conventional alloy wire material having a high strength, copper-metal fiber conductor in which metal such as Nb, Fe, Ag or the like is diffused in Cumatrix thereof (Cu—Nb base alloy, Cu—Nb—Cr base alloy, Cu—Nb—Zr base alloy, Cu—Ta base alloy, Cu—Fe base alloy, Cu—Ag base alloy, Cu—Cr base alloy) can be mentioned. Of the copper-metal fiber conductors, particularly, Cu—Nb base alloy, Cu—Fe base alloy and Cu—Ag base alloy are known to have excellent conductivity, processability and strength.
Further, as another conventional alloy wire material having a high strength and flexing resistance, the core is formed of Cu—Nb base alloy, Cu—Fe base alloy or Cu—Ag base alloy amoung the copper-metal fiber conductors and an external periphery of the core is coated with metal layer composed of Cu and unavoidable impurity, so that a composite cable having excellent conductivity, processability, strength and flexing resistance is produced (see Japanese Patent Application Laid-Open No. 6-290639).
However, because in the copper-metal fiberconductor, the metal fiber is exposed on the surface of the conductor and two kinds of the metals adjoin each other, if water or electrolyte exists, corrosion is likely to occur due to a difference of contact potential. Therefore, the copper-metal fiber conductor has a problem in corrosion resistance.
In the composite cable, the surface of the copper-metal fiber conductor is coated with Cu coating layer so as to prevent a corrosion by a difference of contact potential between different metals. However, if it is used in the atmosphere with the Cu coating layer as it is, it is discolored because of oxidation. If this discoloration is accelerated, copper oxide film is grown so that corrosion resistance reliability of the composite cable drops. For the reason, in the composite cable, a device for preventing discoloration and oxidation corresponding to the environment has been demanded. Generally, to improve corrosion resistance of the Cu cable, the surface of the Cu cable is coated with benzotriazole or plated with Sn, Ag or the like. However, in case where the composite cable is used for application for a small-diameter coaxial cable or the like, if the thickness of the plating layer is small, the Cu is partially exposed so that corrosion resistance reliability drops.
Further, the alloy wire material for use in the small-diameter coaxial cable is demanded to have not only excellent strength, flexing resistance and corrosion resistance but also excellent connectivity in terms of actual use. Here, of the connectivity, reliability (heat resistance) upon coupling at high temperatures by soldering or the like is an important factor.
Further, the alloy wire material used for these applications is demanded to have as small a diameter as possible and to be easy to produce, namely, processed to a long drawn wire. Therefore, this material is demanded to have an excellent processability (particularly, being drawn excellently).
SUMMARY OF THE INVENTION
Accordingly, the present invention intends to solve the above described problems and provide a composite conductor having excellent strength, flexing resistance and corrosion resistance and production method therefor and a cable using the same composite conductor.
To achieve the above object, according to a first aspect of the present invention, there is provided a composite conductor having a corrosion resistant layer 0.5 &mgr;m or more thick constituted of Au, Ag, Sn, Ni, solder, Zn, Pd, Sn—Ni alloy, Ni—Co alloy, Ni—P alloy, Ni—Co—P alloy, Cu—Zn alloy, Sn—Bi alloy, Sn—Ag—Cu alloy, Sn—Cu alloy or Sn—Zn alloy on an external periphery of a core of copper-metal fiber conductor.
According to a second aspect of the present invention, there is provided a composite conductor comprised of a metal coating layer of Cu or Cu alloy on an external periphery of a core of copper-metal fiber conductor and a corrosion resistant layer 0.5 &mgr;m or more thick constituted of Au, Ag, Sn, Ni, solder, Zn, Pd, Sn—Ni alloy, Ni—Co alloy, Ni—P alloy, Ni—Co—P alloy, Cu—Zn alloy, Sn—Bi alloy, Sn—Ag—Cu alloy, Sn—Cu alloy or Sn—Zn alloy on an external periphery of said metal coating layer.
According to a third aspect of the present invention, there is provided a composite conductor according to the first or second aspect wherein the copper-metal fiber conductor is formed of Cu—Nb base alloy, Cu—Ag base alloy or Cu—Fe base alloy.
According to a fourth aspect of the present invention, there is provided a composite conductor according to the third aspect wherein the Cu—Nb base alloy contains Nb of 3-35 mass %.
According to a fifth aspect of the present invention, there is provided a composite conductor according to the third aspect wherein the Cu—Ag base alloy contains Ag of 2-20 mass %.
With the above described structure, the corrosion resistant layer 0.5 &mgr;m or more thick composed of Au, Ag, Sn, Ni, solder, Zn, Pd, Sn—Ni alloy, Ni—Co alloy, Ni—P alloy, Ni—Co—P alloy, Cu—Zn alloy, Sn—Bi alloy, Sn—Ag—Cu alloy, Sn—Cu alloy or Sn—Zn alloy is provided on the external periphery of the cable, thereby ensuring an excellent corrosion resistance.
According to a sixth aspect of the present invention, there is provided a production method for the composite conductor comprising the steps of: applying area reduction processing on a cable of copper-metal fiber conductor; and in the middle of or after the area reduction processing, plating an external periphery of the cable with corrosion resistant layer 0.5 &mgr;m or more thick of Au, Ag, Sn, Ni, solder, Zn, Pd, Sn—Ni alloy, Ni—Co alloy, Ni—P alloy, Ni—Co—P alloy, Cu—Zn alloy, Sn—Bi alloy, Sn—Ag—Cu alloy, Sn—Cu alloy or Sn—Zn alloy.
According to a seventh aspect of the present invention, there is provided a production method for the composite conductor comprising the steps of: forming a cable of copper-metal fiber conductor having Cu or Cu alloy metal coating layer on an external periphery thereof; applying area reduction processing on the cable; and in the middle of or after the area reduction processing, plating an external periphery of the cable with corrosion resistant layer 0.5 &mgr;m or more thick of Au, Ag, Sn, Ni, solder, Zn, Pd, Sn—Ni alloy, Ni—Co alloy, Ni—P alloy, Ni—Co—P alloy, Cu—Zn alloy, Sn—Bi alloy, Sn—Ag—Cu alloy, Sn—Cu alloy or Sn—Zn alloy.
According to an eighth aspect of the present invention, there is provided a production method for the composite conductor comprising the steps of: applying area reducti
Aoyama Seigi
Ichikawa Takaaki
Matsui Hakaru
Nakahigashi Fumitaka
Seya Osamu
Antonelli Terry Stout & Kraus LLP
Hitachi Cable Ltd.
Mayo III William H.
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