Abstract:Effects of trace Ni, P or Ce element additions on the microstructure and the properties of the Sn3.0Ag0.5Cu solder alloy were investigated. Results show that single adding of Ni, P or Ce has little influence on the melting temperature of the Sn3.0Ag0.5Cu solder alloy. P addition can improve the wettability of the solder, i.e. the wetting force of the solder is increased, and the wetting time is decreased. Single adding of Ni or Ce has no significant effect on the wettability of the soldered alloy and the shear strength of the as-reflowed soldered joint, but can remarkably suppress the decrease of the shear strength of the solder joints due to the high-temperature aging. Besides, P addition significantly increases the oxidation resistance of the soldered alloy, but rare earth Ce addition deteriorates it. The property change of the Sn3.0Ag0.5 solder are attributed to the change of the microstructure caused by trace Ni, P, or rare earth Ce additions