Lead-free solder and soldered article

Abstract

A lead-free solder includes at least one selected from 0.01 to 1% by weight of Co, 0.01 to 0.2% by weight of Fe, 0.01 to 0.2% by weight of Mn, 0.01 to 0.2% by weight of Cr, and 0.01 to 2% by weight of Pd; 0.5 to 2% by weight of Cu; and 90.5% by weight or more of Sn. This solder exhibits a satisfactory solderabiliy in solder joints and shows a high resistance to electrode teaching upon soldering or when the resulting soldered article is left at high temperatures.

1 . a lead-free solder consisting essentially of: 
 0.01 to 1% by weight of Co,    0.5 to 9% by weight of Ag,    0.5 to 2% by weight of Cu; and    94.8% by weight or more of Sn.    
     
     
         2 . A soldered article comprising an article containing a transition metal conductor and being joined through a solder, said transition metal conductor being liable to spread in molten Sn, wherein said solder is a lead free solder according to  claim 1 .  
     
     
         3 . A soldered article according to  claim 2 , wherein said transition metal conductor comprises at least one selected from elementary substances or alloys thereof of the group consisting of Cu, Ag, Ni, Au, Pd, Pt and Zn.  
     
     
         4 . A lead-free solder according to  claim 1 , consisting essentially of: 
 0.1 to 1% by weight of Co,    0.5 to 3.5% by weight of Ag,    0.5 to 1% by weight of Cu; and    94.8% by weight or more of Sn.    
     
     
         5 . A soldered article comprising an article containing a transition metal conductor and being joined through a solder, said transition metal conductor being liable to spread in molten Sn, wherein said solder is a lead free solder according to  claim 4 .  
     
     
         6 . A soldered article according to  claim 5 , wherein said transition metal conductor comprises at least one selected from elementary substances or alloys thereof of the group consisting of Cu, Ag, Ni, Au, Pd, Pt and Zn.  
     
     
         7 . A lead-free solder according to  claim 4  consisting essentially of: 
 0.4 to 1% by weight of Co,  
 3 to 3% by weight of Ag,  
 0.5 to 1% by weight of Cu; and  
 94.8% by weight or more of Sn.  
 
     
     
         8 . A soldered article comprising an article containing a transition metal conductor and being joined through a solder, said transition metal conductor being liable to spread in molten Sn, wherein said solder is a lead free solder according to  claim 7 .  
     
     
         9 . A soldered article according to  claim 8 , wherein said transition metal conductor comprises at least one selected from elementary substances or alloys thereof of the group consisting of Cu, Ag, Ni, Au, Pd, Pt and Zn.  
     
     
         10 . A lead-free solder consisting of: 
 0.01 to 1% by weight of Co,    0.5 to 9% by weight of Ag,    0.5 to 2% by weight of Cu; and    94.8% by weight or more of Sn.    
     
     
         11 . A soldered article comprising an article containing a transition metal conductor and being joined through a solder, said transition metal conductor being liable to spread in molten Sn, wherein said solder is a lead free solder according to  claim 10 .  
     
     
         12 . A soldered article according to  claim 11 , wherein said transition metal conductor comprises at least one selected from elementary substances or alloys thereof of the group consisting of Cu, Ag, Ni, Au, Pd, Pt and Zn.