Correlation study of structural, electrical and mechanical properties of quenched tin-zinc-cadmium solder alloys

It is important, for electronic application, to decrease the melting point of SnZn9 solder alloy because it is too high as compared with the most popular eutectic Pb-Sn solder alloy. Adding Cd causes structural changes such as phase transformations, dissolution of atoms and formation of Cd crystals in the quenched SnZng alloy, and its physical properties are affected by this change. For example, the melting point is decreased towards the melting point of the Pb-Sn eutectic alloy, or even much less. The structure, electrical and mechanical properties of quenched Sn91-xZn9Cdx (x = 0 or x greater than or equal to 5) alloys have been investigated. Adding Cd to a quenched SnZng alloy increases its electrical resistivity and decreases its elastic modulus and internal friction. The Sn71Zn9Cd20 alloy has the lowest melting point (162 degreesC) and electrical and internal frictions as compared with commercial Pb-Sn solder alloys.