such as Y2O3-stabilized ZrO2, CaO-stabilized ZrO2 and Al2O3. The equilibrium groove angles, as measured by means of optical interferometry, exhibited no significant dependence upon annealing temperature or atmosphere. The ratios of grain-boundary energy to surface energy ranged from 0.487 to 0.534 for Y2O3-stabilized ZrO2, from 0.452 to 0.534 for CaO-stabilized ZrO2 and from 0.695 to 0.725 for Al2O3. In the case of Al2O3, it was found that surface diffusion was the predominant mass transport mechanism. At temperatures ranging from 1273 to 1763K, such transport depended mainly upon structural damage in the near-surface region that was caused by mechanical polishing. The surface diffusion could be described by:

D (cm2/s) = 0.48 exp[-256(kJ/mol)/RT]

A.Tsoga, D.Sotiropoulou, P.Nikolopoulos: Materials Science Forum, 1996, 207-209, 565-8