Lead (Pb) free solder has been developed to satisfy EU requirements (ROHS) to keep lead out of electronic products.
All lead free solders have a higher melting point than the traditional lead based solders, and does not result in the same smooth shiny surface as we are used to. A lead free solder joint usually gets a gray matte surface.
Several mixtures have been developed to create a solder with low melting point and good wetting.
Sn99.3/Cu0.7 has a melting point of ~ 227°C
Sn95.8/Cu0.7/Ag3.5 has a melting point of ~ 217˚C
Sn96.35/Cu0.5/Ag3.0/Sb0.15 has a melting point of ~ 215 ˚C