Effect of Ni on Performances of Sn2.5Ag0.7Cu0.1RE Solder Alloy and Its Creep Properties of the solder Joints for SMT

Summary form only given. With the development of electronic productions based on lead-free solder, SnAgCuRE as a special lead-free solder alloy in our country, which possess better microjoining technological property and higher mechanical property, has been the hot-point of the microjoining research field. To reduce the manufacturing costs of SnAgCuRE lead-free solder alloy and improve or increase its creep and fatigue properties of soldered joints, with reference to the commercial employed Sn3.8Ag0.7Cu solder, taking Sn2.5Ag0.7Cu0.1RE lead-free solder alloy with lower Ag content as a research object, based on the research of microstructure. mechanical and physical performances and wettability of Sn2.5Ag0.7Cu0.1REXNi solder alloy with lower Ag content fabricated by vacuum condition in this paper. And the creep behavior and its rupture life of Sn2.5Ag0.7Cu0.1REXNi soldered joints were separately investigated under constant temperature by a single shear lap creep specimen with a 1 mm² cross sectional area. The result shows that the performances of Sn2.5AgO.7Cu0.1RE solder alloy and its creep properties of the solder joints can be improved with adding Ni, especially the elongation of Sn2.5Ag0.7Cu0.1RE0.05Ni can be obviously improved without degradation its strength, which is 1.4 times more than that of the commercial employed Sn3.8Ag0.7Cu solder alloy. Accordingly the creep rupture life of its solder joints is the longest , which is 13.3 times more than that of Sn2.5AgO.7Cu0.1RE, and is far superior to that of the commercial employed lead-free solder Sn3.8Ag0.7Cu. Therefore, Ni amount added to the Sn2.5AgO.7Cu0.1RE solder alloy under 0.05% is proper. The results are helpful for the practical application of Sn2.5Ag0.7Cu0.1RE lead-free solder.