Effect of Ni and TiO2 particle addition on the wettability and interfacial reaction of Sn20Bi lead-free solder

In this paper, the powder samples are mechanically ball-milled by powder metallurgy, cold pressed and shaped, then melted, and finally, the samples are wire cut to the proper size and wetted to obtain composite solder joints under the action of reflow. The effects of Ni and TiO2 powders on the microstructure and wettability of Sn-20Bi composite solder joints were investigated, and the morphological growth of interfacial intermetallic compounds (IMCs) was evaluated and analyzed. The results show that the addition of appropriate amounts of Ni and TiO2 powders can refine the microstructure of the composite solder and improve the wettability. The addition of Ni particles could not inhibit the growth of the Interfacial intermetallic compounds (IMCs) layer. In contrast, the addition of TiO2 particles could effectively inhibit the growth of the IMCs layer of Sn20Bi composite solder.