Polished polycrystalline samples were annealed at high temperatures, and the resultant grain boundary grooving behavior was monitored. From these observations, the surface diffusion coefficient was calculated to be given by:

D(cm2/s) = 9.39 x 106exp[-3.09(eV)/kT]

W.M.Robertson: Journal of the American Ceramic Society, 1981, 63[1], 9-13