Effect of Er and Ni-CNTs on the interfacial reaction and growth behavior of Sn58Bi/Cu intermetallic compound layers

The interface reaction of Sn58Bi solder with 0.1% Er (0%, 0.01%, 0.03%, 0.05% and 0.1% ni-cnts) was studied after refluxing and solid aging. The results show that the growth of IMC layer is inhibited by Er and Ni-CNTs. After aging at 100 °C for 200 and 400 h, the addition of Er and Ni-CNTs inhibited the growth of total IMC layer and Cu3Sn layer was inhibited by the addition of Er and Ni-CNTs. During aging process, the thickness of interface (Cu,Ni) 6Sn5 layer under Ni-CNTs and Er addition is always thinner than that under Er addition, because Ni-CNTs can effectively reduce the CTE of SnBi solder. The reason why the growth rate of Cu3Sn with Er and Ni-CNTs is lower than that with Er alone is that the stability of (Cu, Ni) 6Sn5 is improved with the increase of Ni content in Ni-CNTs. In addition, the IMC growth rate of composite weld decreases with the increase of Ni-CNTs content.