Grain-boundary grooves and surface diffusion in polycrystalline alumina measured by atomic force microscope

Grain-boundary grooving was studied on polished surfaces of polycrystalline alumina, after it was annealed at 1370 similar to 1600 degrees C in air. The groove angles and the groove widths were measured by AFM and it ,uas determined that surface diffusion is the dominant mechanism for the mass transport and the ratio of grain-boundary energy to surface energy decreased with increasing temperature. The surface diffusion coefficient calculated was D-s = 8.22 x 10(7) x exp[-577 +/- 30 (kJ mol(-1))/RT] which is the smallest among those reported in the literature. (C) 1998 Elsevier Science Limited. All rights reserved.