Alpha uranium dicarbide disks coated with pyrolytic carbon migrate, relative to the carbon, up a temperature gradient, leaving behind a layer of rejected graphite. A model for the migration process based on solution of carbon at the hot UC2‐C interface, transport across the UC2phase by thermal diffusion, and rejection as graphite at the cool UC2‐C interface was developed. The rate of migration may be described by:The apparent activation energy for migration is 76.5±9 kcal/mol, compared to a literature value for carbon self‐diffusion inα‐UC2of 90.2 kcal/mol. This difference in temperature dependence may be considered preliminary evidence that the heat of transport decreases with increasing temperature. The average value of the heat of transport, calculated using literature values for carbon self‐diffusion inα‐UC2, is