Comment on "The effects of buoyancy convection on the measured solute diffusion coefficients in dilute metallic liquids" [ J. Appl. Phys. 96 , 6213 ( 2004 ) ]

Two main problems have been identified with this recently published paper: (1) The authors claim that the terrestrial and microgravity experiments were performed under isothermal conditions to render any thermotransport insignificant. Close examination of the problems encountered during processing of the capillary diffusion couples on the MIR space station reveals that this claim cannot be justified. (2) On the basis of experimental results, the authors conclude that the diffusion coefficients of gold and silver in lead measured on the ground are much higher than those obtained under microgravity. This conclusion is questionable because the methodology used to determine the processing time and temperatures on the MIR space station does not seem to be scientific.