Is there a lead-free solder with a low melting point?
There are lead-free alloys for solder paste with 35-58% Bi content and others containing a variety of elements such as zinc with a lower bismuth contents, example Sn89Zn8Bi3. Bi is effective to lower the melting point but it also makes solders weak and brittle. Bismuth does lower the melting point and improves wetting but has limitations. Zn oxidizes very quickly and needs extreme caution when used due to its electrolytic corrosion potential. Primarily consumer electronic assemblers use these alloys.
