Experimentally determined self-diffusion coefficients were reported for carbon in type-IaA diamond under pressure and temperature conditions within the diamond stability field at 10GPa and 2075 to 2375K (table 11, figure 5). The results could be described by:

D (m2/s) = 4.1 x 10-5exp[-6.8(eV)/kT]

The activation energy was approximately 30% lower than results predicted previously from ab initio calculations.

Carbon Self-Diffusion in a Natural Diamond. Koga, K.T., Walter, M.J., Nakamura, E., Kobayashi, K.: Physical Review B, 2005, 72[2],

 024108

Figure 5

Diffusion of C in diamond