Measurements of groove width were performed, at temperatures ranging from 1200 to 1500C, on dense sintered polycrystalline samples. At temperatures of between 1200 and 1350C, grooving was found to proceed via a surface diffusion mechanism and the results could be described by:

D (cm2/s) = 1800 exp[-330(kJ/mol)/RT]

At temperatures above 1450C, grooving occurred via a volume diffusion mechanism.

M.Ceh, D.Kolar: Journal of Materials Science, 1989, 24[12], 4307-10