The Variations of Electron and Phonon Contributions to the Thermal Conductivity with Temperature in the Sn–Bi–In–Zn Alternative Lead-Free Solder Alloys

The goal of this paper is to measure the electrical and thermal conductivity variations with temperature in the unidirectional solidified quaternary Sn–Bi–In–Zn lead-free solder alloys for nine different compositions to determine the phonon thermal conductivity variation with temperature. The measurements of electrical and thermal conductivity variations with temperature were put into practice with the methods of four-point probe and longitudinal heat flow, respectively, and the electron and phonon thermal conductivity variations with temperature for the alloys were plotted. In addition, the temperature coefficient values for electrical and thermal conductivity were calculated.