Superfine copper alloy wire and method for manufacturing same

Abstract

A superfine copper alloy wire has a copper-silver alloy wherein the superfine copper alloy wire has a final wire diameter of 0.05 mm or less, and the copper-silver alloy has a copper-silver eutectic crystal phase whose volume ratio to a whole volume of the superfine copper alloy wire is 3% or more and 20% or less.

1 . A superfine copper alloy wire comprising: 
 a copper-silver alloy;    wherein the superfine copper alloy wire has a final wire diameter of 0.05 mm or less, and    the copper-silver alloy comprises a copper-silver eutectic crystal phase whose volume ratio to a whole volume of the superfine copper alloy wire is 3% or more and 20% or less.    
     
     
         2 . The superfine copper alloy wire according to  claim 1 , wherein: 
 the volume ratio to the whole volume of the superfine copper alloy wire is 5% or more and 15% or less.    
     
     
         3 . The superfine copper alloy wire according to  claim 1 , wherein: 
 the copper alloy comprises a weight ratio of silver to copper that is 1.0 wt % or more and 3.5 wt % or less.    
     
     
         4 . The superfine copper alloy wire according to  claim 1 , wherein: 
 the copper alloy comprises a weight ratio of silver to copper that is 1.5 wt % or more and 3.0 wt % or less.    
     
     
         5 . The superfine copper alloy wire according to  claim 1 , wherein: 
 the superfine copper alloy wire comprises a tensile strength of 800 MPa or more, and an electric conductivity of 80% IACS or more.    
     
     
         6 . A superfine copper alloy wire, comprising: 
 a main wire body comprising a copper-silver alloy; and    a silver film formed around the main wire body,    wherein the superfine copper alloy wire has a final wire diameter of 0.05 mm or less, and    the copper-silver alloy comprises a copper-silver eutectic crystal phase whose volume ratio to a whole volume of the superfine copper alloy wire is 3% or more and 20% or less.    
     
     
         7 . The superfine copper alloy wire according to  claim 6 , wherein: 
 the volume ratio to the whole volume of the superfine copper alloy wire is 5% or more and 15% or less.    
     
     
         8 . The superfine copper alloy wire according to  claim 6 , wherein: 
 the copper alloy comprises a weight ratio of silver to copper that is 1.0 wt % or more and 3.5 wt % or less.    
     
     
         9 . The superfine copper alloy wire according to  claim 6 , wherein: 
 the copper alloy comprises a weight ratio of silver to copper that is 1.5 wt % or more and 3.0 wt % or less.    
     
     
         10 . The superfine copper alloy wire according to  claim 6 , wherein: 
 the superfine copper alloy wire comprises a tensile strength of 800 MPa or more, and an electric conductivity of 80% IACS or more.    
     
     
         11 . A method for manufacturing a superfine copper alloy wire having a final wire diameter of 0.05 mm or less, comprising the steps of: 
 pouring a copper alloy hot metal prepared by allowing 1.0 wt % or more to 3.5 wt % or less of Ag to contain in a copper parent material having a total sum of 10 ppm or less of impurity concentrations into a casting mold to implement metal casting;    cooling an uncoagulated copper alloy hot metal after the pouring at a cooling rate of 400° C./min or more to 500° C./min or less to form a casting;    cold-working the casting for reducing a diameter thereof; and    recrystallizing a wiredrawn material obtained as a result of the cold working.    
     
     
         12 . The method for manufacturing a superfine copper alloy wire as defined in  claim 11 , wherein: 
 the recrystallizing step comprises a heat treatment at a temperature of 300° C. or more to 550° C. or less for 0.5 to 20 hours.    
     
     
         13 . The method for manufacturing a superfine copper alloy wire as defined in  claim 12 , wherein: 
 the wiredrawn material after the heat treatment is quenched.    
     
     
         14 . The method for manufacturing a superfine copper alloy wire as defined in  claim 11 , wherein: 
 the recrystallizing step comprises a rapid heating at a temperature of 600° C. or more to 900° C. or less for 5 to 120 seconds, and a quenching treatment is followed.    
     
     
         15 . The method for manufacturing a superfine copper alloy wire as defined in  claim 11 , wherein: 
 a silver plating is applied to the wiredrawn material after the recrystallizing step.