Thermodynamic Assessment of Interaction Relation between Lanthanum and Constituent Elements in Sn-Pb Alloy

The interaction relation between lanthanum and the constituent elements of Sn Pb alloy system was analyzed by using the thermodynamic models including Miedema formation energy model for binary system, Tanaka modification by excess entropy and the Chou geometric model for ternary system. The thermodynamic calculaton results show that lanthanum has higher affinity for Sn in the Sn Pb system. This is an important foundation for the improvement of the metallurgical properties of Sn Pb solder alloy by adding rare earth elements.