Phase Equilibria of the Fe-Sn-Zn Ternary System at 270°C

A clear understanding of the isothermal section of the Fe-Sn-Zn ternary system in the soldering temperature range is necessary to ensure solder joint reliability between Fe and Sn-Zn alloys. To determine the isothermal section of Fe-Sn-Zn ternary system at 270°C, 19 Fe-Sn-Zn alloys with different compositions were prepared. The characterization results, such as optical microscope, scanning electron microscope, energy dispersive spectroscopy and X-ray diffraction, will be discussed in this study. The experimental results confirmed that the FeSn2 phase had up to 2.2 at.%Zn solubility while the other phases exhibited almost no ability to dissolve a third element. Moreover, 9 single-phase, 13 two-phase, and 7 three-phase regions, with no ternary IM Cs were found in this isothermal section. The phase equilibria of the Fe-Sn-Zn ternary system at 270°C were experimentally established.