Structure, electrical, mechanical and wettability of quenched lead-free solder alloys

The experimental results obtained from the double bridge method, Vickers microhardness tester and dynamic resonance technique are used to evaluate the electrical resistivity, hardness, internal friction and elastic properties of binary, ternary and quaternary tin based lead-free solder alloys. In addition, structure and wettability of these solder alloys have been studied and analyzed. The quenched Sn91Zn9 Bi1Cu2 lead-free solder alloy has better properties than the others as a soft solder, such as a low melting point of 194.7 degrees C, low electrical resistivity, high strength, adequate wettability and low internal friction for low temperature solder applications. In addition, the SnAg5 quenched alloy has good properties as a hard solder, such as a high melting temperature 228.17 degrees C, high elastic modulus and low internal friction for high temperature solder applications. Adding Bi and Cu to SnZn9 improves its soldering physical properties.