Influence of Sb on Sn-0.7Cu solder' s melting point and soldering interface

The influences of Sb (0.25%, 0.5%, 0.75% and 1.0%)on Sn -0.7Cu lead-free solder's melting point and soldering interface was studied by scanning electron microscope and differential scanning calorimetry equipment.The result indicates that the melting point raises from 226.38℃ to 227.09℃ as Sb was added into the SnCu solders from 0.25% to 1.0%.But the melting point changed a little when Sb is less than 0.75%, only when its content comes up to 1.0% the melting point changed obviously. When SnCu solder contains 0.5% Sb, the pattern of IMC(intermetallis compound)changes obviously, scalloplike IMC becomes smooth and the thickness of IMC becomes small and big prismatical Cu₆Sn₅ is avoided;the growth of IMC is inhibited and the grain is refined. When more than 0.5% Sb is added into the solder, the big prismatical Cu₆Sn₅ is formed again and IMC becomes thicker.The spiece of IMC wasn't changed when Sb is added into Sn-0.7Cu solder.