Abstract
In order to clarify the relative importance of various factors for the solute diffusion in liquid metals as reference data for a theoretical prediction of solute diffusion coefficients the diffusion coefficients of the fifth period solutes (Ru, In, Sn and Sb) in liquid copper have been measured in the temperature range 1100 to 1300°C by the capillary reservoir method. The results obtained are summarized as follows:
(1) The solutes belonging to the fifth period in molten copper diffuse faster than the solvent atom. The diffusion coefficients obtained are in the order of DSn>DRu>DAg>DSb>DIn.
(2) The temperature dependence of diffusion coefficients obtained can be represented by the Arrhenius type equation. The apparent activation energy for diffusion of the solute in molten copper increases with increasing valence of the solute.
(3) There is some correlation between the thermodynamic property and diffusion in these systems. The larger the activity coefficient of the solute, the faster diffuses the solute.
(4) The diffusion coefficients of solutes in molten copper were estimated on the basis of the hard sphere theory originally derived by Enskog. Although the calculated and the observed diffusion coefficients agree well at 1200°C, the apparent activation energies calculated show somewhat poor agreement with the calculated ones.
