Effect of content of Ni on wettability and shear strength of BiSbSnNi solder alloy

It is one of difficult problems to research and develop the high temperature lead-free soft solder in the brazing field. Bi5Sb8 Sn solder with the melting point of around 270℃ islimited because its wettability and shear strength could not meet the requirements. A new BiSbSnNi quaternary alloy was prepared by adding different content of Ni in Bi5Sb8 Sn to improve the wettability and mechanical properties of Bi5Sb8 Sn alloy. Results show that adding Ni makes Bi5Sb8 Sn solder alloy spreadability worse than that of matrix solder. However, when the content of Ni is 2%, both the solder intermetallic compounds formation and the spreading area can increase. When the Ni content is 3%, the shear strength of the Bi5Sb8Sn3 Ni alloy reaches the maximum. When the Ni content is 4%, the IMC thickness increases significantly and a lot of strip Bi phase emerges, which has an adverse effect on the shear strength of the soldered joint..