Ultrafine copper alloy wire, stranded copper alloy wire conductor, extrafine coaxial cable, and process for producing ultrafine copper alloy wire

Abstract

A wire rod comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass is drawn to an ultrafine copper alloy wire with a diameter of not more than 0.08 mm. According to this constitution, since the content of foreign matter, causative of breaking of wires, in a base material has been minimized, excellent wire drawability and bending properties can be realized. Further, since silver is used as an additive element, the ultrafine copper alloy wire possesses excellent tensile strength. This constitution can further realize a stranded copper alloy wire conductor, and an extrafine coaxial cable possessing excellent tensile strength, wire drawability, and bending properties.

What is claimed is:  
     
         1 . An ultrafine copper alloy wire with a diameter of not more than 0.08 mm, 
 said ultrafine copper alloy wire being formed of a copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass.    
     
     
         2 . An ultrafine copper alloy wire with a diameter of not more than 0.08 mm, 
 said ultrafine copper alloy wire being formed of a copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.5% by mass of magnesium having a purity of not less than 99.9% by mass.    
     
     
         3 . An ultrafine copper alloy wire with a diameter of not more than 0.08 mm, 
 said ultrafine copper alloy wire being formed of a copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.3% by mass of indium having a purity of not less than 99.99% by mass.    
     
     
         4 . The ultrafine copper alloy wire according to  claim 1 ,  2 , or  3 , wherein said copper alloy wire has thereon a tin plating, a silver plating, a nickel plating, a tin-lead solder plating, a tin-silver plating, a tin-copper plating, a tin-silver-copper plating, or a tin-silver-copper-bismuth plating.  
     
     
         5 . A stranded copper alloy wire conductor comprising a plurality of copper alloy wires with a diameter of not more than 0.08 mm stranded together, 
 said copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass.    
     
     
         6 . A stranded copper alloy wire conductor comprising a plurality of copper alloy wires with a diameter of not more than 0.08 mm stranded together, 
 said copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.5% by mass of magnesium having a purity of not less than 99.9% by mass.    
     
     
         7 . A stranded copper alloy wire conductor comprising a plurality of copper alloy wires with a diameter of not more than 0.08 mm stranded together, 
 said copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.3% by mass of indium having a purity of not less than 99.99% by mass.    
     
     
         8 . An extrafine coaxial cable comprising a copper alloy wire with a diameter of not more than 0.08 mm provided for constituting an inner conductor or an outer conductor, 
 said copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass.    
     
     
         9 . An extrafine coaxial cable comprising a copper alloy wire with a diameter of not more than 0.08 mm provided for constituting an inner conductor or an outer conductor, 
 said copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.5% by mass of magnesium having a purity of not less than 99.9% by mass.    
     
     
         10 . An extrafine coaxial cable comprising a copper alloy wire with a diameter of not more than 0.08 mm provided for constituting an inner conductor or an outer conductor, 
 said copper alloy wire comprising high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass and, added to the high-purity copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.3% by mass of indium having a purity of not less than 99.99% by mass.    
     
     
         11 . The extrafine coaxial cable according to  claim 8 ,  9  or  10 , wherein the inner conductor comprises a plurality of the copper alloy wires stranded together.  
     
     
         12 . A process for producing an ultrafine copper alloy wire, comprising the steps of: 
 melting a high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass in a carbon crucible installed in a vacuum;    replacing an atmosphere surrounding the melted copper by an argon gas atmosphere and adding 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass to said copper;    casting said copper with silver added thereto in a carbon mold into a wire rod; and    drawing said wire rod to a diameter of not more than 0.08 mm.    
     
     
         13 . A process for producing an ultrafine copper alloy wire, comprising the steps of: 
 melting a high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass in a carbon crucible installed in a vacuum;    replacing an atmosphere surrounding the melted copper by an argon gas atmosphere and adding, to said copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.5% by mass of magnesium having a purity of not less than 99.9% by mass;    casting said copper with silver and magnesium added thereto in a carbon mold into a wire rod; and    drawing said wire rod to a diameter of not more than 0.08 mm.    
     
     
         14 . A process for producing an ultrafine copper alloy wire, comprising the steps of: 
 melting a high-purity copper having a total unavoidable impurity content of not more than 1 ppm by mass in a carbon crucible installed in a vacuum;    replacing an atmosphere surrounding the melted copper by an argon gas atmosphere and adding, to said copper, 1.0 to 5.0% by mass of silver having a purity of not less than 99.99% by mass and 0.01 to 0.3% by mass of indium having a purity of not less than 99.99% by mass;    casting said copper with silver and indium added thereto in a carbon mold into a wire rod; and    drawing said wire rod to a diameter of not more than 0.08 mm.