Tin-indium based lead-free solders with zinc addition

Abstract

A new kind of Sn—In based Pb-free solders with Zn addition is disclosed, which includes: 15˜25 wt % In; 0.05˜1.5 wt % Zn; and balance Sn. When the solder of the present invention is used in the assembly of electrical products, the dissolution rates of the substrates and the growth of the intermetallic compounds formed at the interfaces can be reduced; and thereby the properties of joints can be improved.

1 . A lead-free solder, comprising:
 indium of 15-25 wt %;   zinc of 0.05-1.5 wt %; and   balance tin.   
     
     
         2 . The lead-free solder as claimed in  claim 1 , further comprising: a first metal of 0.01-2.0 wt %, selected from the group consisting of Sb, Bi, Ge, Fe, Al, Ag, Cu, Ce and La. 
     
     
         3 . The lead-free solder as claimed in  claim 2 , further comprising: a second metal of 0.01-2.0 wt %, selected from the group consisting of Sb, Bi, Ge, Fe, Al, Ag, Cu, Ce and La. 
     
     
         4 . The lead-free solder as claimed in  claim 1 , comprising: indium of 15-25 wt %, zinc of 0.05-1.5 wt %, and tin of 73.5-84.95 wt %. 
     
     
         5 . The lead-free solder as claimed in  claim 1 , comprising: indium of 20 wt %, zinc of 0.05-1.5 wt %, and tin of 78.5-79.95 wt %. 
     
     
         6 . The lead-free solder as claimed in  claim 1 , comprising: indium of 20 wt %, zinc of 0.5-1.0 wt %, and tin of 79-79.5 wt %. 
     
     
         7 . The lead-free solder as claimed in  claim 1 , comprising: indium of 20 wt %, zinc of 0.5 wt %, and tin of 79.5 wt %. 
     
     
         8 . The lead-free solder as claimed in  claim 1 , comprising: indium of 20 wt %, zinc of 0.7 wt %, and tin of 79.3 wt %. 
     
     
         9 . The lead-free solder as claimed in  claim 1 , comprising: indium of 20 wt %, zinc of 1.0 wt %, and tin of 79.0 wt %.