Thermal conductivity of liquid metals and metallic alloys

Abstract

The aim of this work is to show that the electrical resistivity and the thermoelectric power can be used to determine the thermal conductivity of liquid metals and alloys. We have made this determination for liquid aluminum, tin, lead, copper and metallic alloys Cu–Al, Ag–Ga, Ag–Ge, Cu–Pb, In–Mn, Ga–Ge and Sn–Bi. For these calculations, we used the relations between the transport coefficients that can be simplified to the Wiedemann–Franz law. For the pure metals studied, our calculated thermal conductivities are near experimental determinations from different authors, showing that the Wiedemann–Franz law is valid. We predict that the Al–Cu liquid alloy has a minimum in the thermal conductivity, and in its temperature coefficient versus concentration at 20 at.% of aluminum. This result is in agreement with the magnetic susceptibility data, and with the superficial tension that have unusual magnitudes near this concentration. It is also consistent with the existence of an eutectic near the same concentration. Nevertheless, it is in contradiction with other data also deduced from resistivity measurements. We do not have any explanation of that disagreement. We show that a minimum in the thermal conductivity isotherm is also obtained for other noble-polyvalent liquid metal alloys studied, i.e. Ag–Ga and Ag–Ge. The only exception is the Cu–Pb alloy for which the calculated thermal conductivity varies monotonically with concentration.