Density measurement of Sn-40Pb, Sn-57Bi, and Sn-9Zn by indirect Archimedean method

By the indirect Archimedean method, the density and the density-temperature relationship of the Sn-40Pb eutectic alloy and two rho b-free solders, Sn-57Bi and Sn-9Zn eutectic alloys, were measured from room temperature to about 250 degrees C. The results showed that the density-temperature dependence for each alloy in both solid and melting states can be fitted linearly as rho s(Sn-40Pb) = 8.51 - 8.94 x 10(-4) (T-25(degrees)C), rho L(Sn-40Pb) = 8.15 - 13.8 x 10-4 (T-T-m); rho s(Sn-57Bi) = 8.54 -5.86 X 10(-4) (T-25 degrees C,rho L(Sn-57Bi) = 8.51 - 10.9 x10-4 (T-Tm); and rho s(Sn-9Zn) = 7.22 - 7.78 x 10(-4) (T-25 degrees C), rho L(Sn-9Zn) = 6.89 - 5.88 x 10(-4) (T - T-m), where the density unit was g/cm(3). At the melting point, density of the melt of these solders is 8.15 g/cm 3, 8.51 g/cm(3), and 6.89 g/cm(3), respectively. The density decreased 2.6% for Sn-40Pb eutectic alloy during melting, and 2.7% for Sn-9Zn eutectic alloy, but increased 0.5% for Sn-57Bi eutectic alloy. The excess molar volume for these alloys after mixing at their melting point is 0.03 cm(3)/mol for Sn-40Pb, 0.09 cm(3)/mol for Sn-57Bi, and 0.21 cm(3)/mol for Sn-9Zn.