On the Interpretation of the Heat of Transport of Substitutional Impurities in Noble Metals

Abstract

Abstract The heats of transport of several substitutional impurities (such as Sb, Sn, In, Ag, N i and Co) in copper and silver are discussed in terms of atomic quantities. They are considered as consisting of essentially two parts. The first one, the so-called intrinsic heat of transport, can be derived from the electrostatic potential generated by the impurity at the site of a normal lattice atom in excess over the potential of the host lattice. This interpretation is com patible with the therm­odynamic definition of the heat of transport. The calculations were carried out for fee lattices but, in principle, may be easily extended to other alloy structures. The second part, calculated by Gerl, is due to the electronic scattering potential of the impurities. From comparison of theore­tical and observed data of heats of transport one finds the agreement to be very good. This is taken to be an indication of the validity of the theoretical models used and of the vacancy mechanism as the dominating mass transport mechanism in these systems, not only in a uniform temperature field but also in a temperature gradient