Effect of γ-Fe2O3 nanoparticles size on the properties of Sn-1.0Ag–0.5Cu nano-composite solders and joints

Abstract

In this study, the Sn1.0Ag0.5Cu–0.5 Fe2O3 (SAC105–0.5 Fe2O3) composite solders reinforced by γ-Fe2O3 nanoparticles with size of 20 nm, 50 nm and 200 nm, respectively, were prepared by alloy melting method. The effect of nanoparticles size on microstructure, melting properties and wettability of the SAC105–0.5 Fe2O3 composite solder alloys, the interfacial intermetallic compounds (IMCs) growth on Cu substrate and the shear strength of the composite solder/Cu joints were investigated. The results indicated that the size of the added γ-Fe2O3 nanoparticles in the composite SAC105–0.5 Fe2O3 solders is critical to the properties of the solder alloys and solder/Cu joints. When the added γ-Fe2O3 nanoparticles size changed from 200 nm to 20 nm, the microstructure of the composite solder refined, the liquidus temperature of the composite solders decreased slightly and the wettability of the composite solder increased. The addition of smaller-size γ-Fe2O3 nanoparticles suppressed the interfacial IMCs formation during reflow and impeded the interfacial IMC growth during thermal aging more effectively. Smaller-size γ-Fe2O3 nanoparticles also improved the shear strength and the ability of plastic deformation of the solder joints more effectively. In addition, the mechanisms of the nanoparticles size effect were discussed.