▎ 摘　　要

Sn-3.5Ag lead-free solder an appropriate candidate for soldering due to its reasonable cost. In this study, 0.07 wt % graphene nanosheets were added into the Sn-3.5Ag solder to improve the intermetallic layer growth and the solder was prepared using powder metallurgy route. The composite solder was soldered on copper substrate at 250 degrees C for one minute and aged until 500 h at 100, 125, 150 and 180 degrees C. Cu6Sn5 intermetallic layer was the first layer formed at the interface and Cu3Sn formed at higher aging conditions. The composite solder shows lower total intermetallic thickness, hence lower intermetallic growth rate. The growth rate was used to calculate the activation energies for total intermetallic layers growth and reported as 65.9 and 77.0 kJ/mol for Sn-3.5Ag and Sn-3.5Ag-0.07GNSs solder joints, respectively.