Kinetics of surface area changes in glasslike carbon: reanalysis of the data

Abstract

Previous small-angle scattering measurements of the kinetics of changes of the surface area of pores in an annealed glasslike carbon have been reanalyzed in terms of the Lifschitz, Slyozov, and Wagner coarsening theory in which the surface area is used to obtain an average spherical pore size. When the data are corrected for the transient heat-up time to reach the annealing temperature, the reanalysis leads to an activation energy of 75 ± 7.2. kcal/mol, in agreement with recent results (75 ± 3.6 kcal/mol) obtained using direct measurements of changes in pore size as determined by the pore radius of gyration. The best value for the activation energy for vacancy migration in carbon is therefore estimated at 75 ± 3.2 kcal/mol.