Abstract:
The electrical and thermal conductivity variations with temperature for lead-free ternary solders, namely
Sn-41.39 at.% Cd-6.69 at.% Sb, Sn-49 at.% In-1 at.% Cu, Sn-50 at.% Ag-10 at.% Bi and Sn-32 at.% Bi-3 at.% Zn
alloys, were measured by the d.c. four-point probe method and radial heat flow apparatus, respectively.
The contributions of electrons and phonons to the thermal conductivity were separately determined by
using the measured values of the thermal and electrical conductivities obtained by the Wiedemann
eFranz law in the lead-free ternary solders. The percentages of the phonon component of thermal
conductivity were found to be in the range of 46e55%, 46e50%, 38e47% and 69e73% for Sn-41.39 at.%
Cd-6.69 at.% Sb, Sn-49 at.% In-1 at.% Cu, Sn-50 at.% Ag-10 at.% Bi and Sn-32 at.% Bi-3 at.% Zn alloys at the
ranges of 318e443 K temperature, respectively. The temperature coefficients (a) of electrical conductivity
for the lead-free ternary solders were found to be 2.47 10 3
, 4.97 10 3
, 1.14 10 3 and
1.00 10 3 K 1
, respectively. The thermal conductivities of the solid phases at their melting temperature
and the thermal temperature coefficients for the lead-free ternary solders were also found to be
47.72 ± 2.38, 68.57 ± 3.42, 73.52 ± 3.67, 37.53 ± 1.87 W/Km and 1.47 10 3
, 1.48 10 3
, 1.85 10 3 and
2.21 10 3 K 1
, respectively