Rate of Solution of Rotating Tantalum Disks in Liquid Tin

Abstract

The dissolution kinetics of tantalum in liquid tin have been investigated under the well‐defined hydrodynamic conditions produced by the rotating‐ disk sample geometry. Dissolution data were obtained under laminar flow conditions (Reynolds No. ) for the temperature range 800°– 1200°C. Much of the experimental data was found to be in a region of mixed transport control; however, for specific conditions of temperature and velocity, both limiting cases for reaction and diffusion control were also observed. The solubility of tantalum in liquid tin was determined over the temperature range 600°–1200°C. The diffusion coefficient of Ta‐182 in liquid tin was also measured at temperatures between 500° and 1100°C by the capillary‐reservoir method. These data were used in the conyective‐diffusion model set forth by Levich to calculate values for the diffusion‐controlled dissolution flux. The model was extended to include the range of Schmidt numbers between 4 and 1000. A Schmidt number of ∼25 in the tantalum‐tin system at 1200°resulted in a 12% reduction in the calculated dissolution flux. Within the limits of error of the experimental diffusion data, the dissolution flux from the model was in agreement with the experimental values in the region of diffusion control.