Effects of Nano-Tio2 Particles Additions on Microstructure Development And Hardness of Sn3.5Ag0.5Cu Composite Solder
The effects of nano-TiO particle additives on the microstructure and microhardness of the 2 Sn3.5Ag0.5Cu composite solder were studied. Results show that alloying with nano-TiO 2 particles dramatically reduced the formation of primary ß-Sn phase,the average size of Ag3Sn phase,and the spacing lamellae in the Sn3.5Ag0.5Cu composite solder. This is attributed to the adsorption of nano-TiO2 particles with high surface free energy on the grain surface during solidification. Microhardness improved with the addition of nano-TiO 2 particles,which refinded Ag Sn INCs. The refined IMCs acted as a strengthening phase in the 3 solder matrix and enhanced the Vicker’s microhardness of the Sn3.5Ag0.5Cu composite solders,which corresponds well with the prediction of the classic dispersion strengthening theory.