LAUSR

The effect of trace ZrC on the wettability, microstructure and mechanical properties of Sn-9Zn composite solder alloy joints was investigated. The results indicated that the wettability of the Sn-9Zn based composite solder alloy was improved and the microstructure was refined by adding appropriate amount nanoparticle ZrC. The microstructure of Sn-9Zn based composite solder alloys consists of primary Sn and Sn-Zn eutectic, and the excellent wettability and refined microstructure can be obtained by adding about 0.06 wt% ZrC. The interfacial intermetallic compounds (IMC) layer in the Sn-9Zn based composite solder alloy joints consists of Cu5Zn8 and Cu6Sn5. IMC layer thickness of Sn-9Zn based composited solder alloys joints is increased with increasing ZrC content. The tensile strength and the shear strength of Sn-9Zn based composite solder alloys joints relate to the ZrC content, and the maximum mechanical properties of solder joints are obtained by adding about 0.06 wt% ZrC, and the fracture mechanism of the Cu/Sn-9Zn-(0-0.09) ZrC/Cu solder joints is ductile fracture.