Wettability Studies of Pb-Free Soldering Materials

Abstract

For Pb-free soldering materials, two main substitutes are currently being considered, consisting of Sn-Ag and Sn-Ag-Cu eutectics, both with melting points higher than that of the Sn-Pb eutectic. Therefore, both will require higher soldering temperatures for industrial applications. Also, both eutectics have a higher surface tension than the Sn-Pb eutectic, requiring wettability studies on adding Bi, Sb, and In to the eutectics to decrease the melting points and surface tension. The experimental results for the surface tension were compared with thermodynamic modeling by Butler's method and were used to create the SURDAT database, which also includes densities for pure metals, binary, ternary, quaternary, and quinary alloys. To model the surface tension, excess Gibbs energies of the molten components were taken from the ADAMIS database. For the case of the Ag-Sn system, enthalpies of formation of Ag 3 Sn from solution calorimetry were used for checking optimized thermodynamic parameters. In the study of Sn-Ag-Cu-Bi-Sb liquid alloys, the range of possible Bi compositions for practical applications has been used to formulate a generalized metric of wettability, which was checked by measurements of the influence of In on the Sn-Ag-Cu system.

Effect of Graphene Layers on Phenomena Occurring at Interface of Sn-Zn-Cu Solder and Cu Substrate

“…At present, the commonly applied alternatives are based on Sn-Ag and Sn-Ag-Cu (SAC) eutectics. The properties of these alloys have been widely studied, [1][2][3][4] revealing several disadvantages. Solder alloys based on Sn-Zn are competitive because of their lower manufacturing cost, which is estimated to be approximately 50% lower than in the case of Sn-Ag and Sn-Ag-Cu alloys.…”

Wetting and interface phenomena in the molten Sn/CuFeNiCoCr high-entropy alloy system

“…The values of the contact angle indicate the degree of wettability [17] : (0° <  < 30°) very good wetting, (30° <  < 40°) good wetting, (40° <  < 55°) acceptable wetting, (55° <  < 70°) poor wetting, and ( >70°) very poor wetting. Therefore, the wetting performance of Sn/CuFeCoNiCr HEA system changes from "very poor wetting" to "very good wetting" with increasing of the temperature from 573 K to 923 K, which shows a strong effect of temperature on wettability.…”

Early stages of wetting of copper by Sn–Zn eutectic alloy

“…Concerning the solders employed in electronics the research has been focused mainly on Sn-Ag, Sn-Ag-Cu systems with eutectic composition and with various alloying dopants [7,8]. The properties of these alloys have been widely studied and revealed a number of drawbacks, one of which is the high melting point [9][10][11].…”