Thermodynamic properties of the liquid Ag–Cu–Sn lead-free solder alloys

The electromotive force measurement method was employed to determine the thermodynamic properties of liquid Ag–Cu–Sn alloys using solid electrolyte galvanic cells as shown below:Kanthal+Re,   Ag–Cu–Sn,   SnO2|Yttria   stabilized   Zirconia|air,   Pt,   pO2=0.21 atmMeasurements were carried out for three cross-sections with constant Ag/Cu ratio equal to: 1/3, 1 and 3 and for tin compositions ranging from 10 up to 80 at.%, every 10%, resulting in a total of 24 different alloy compositions. The temperature of the measurements varied within the range from 973 to 1325 K. A linear dependence of the e.m.f. on temperature was observed for all alloy compositions and the appropriate line equations were derived. Tin activities were calculated as function of composition and temperature. Results were presented in tables and figures.