Equilibrium Shape of Internal Cavities in Ruby and the Effect of Surface Energy Anistropy on the Equilibrium Shape

Published

July 1, 2002

Author(s)

J S. Choi, D Y. Kim, B Hockey, Sheldon M. Wiederhorn, J Blendell, C A. Handwerker

Abstract

vities formed in ruby (99.46Al2O3-0.54Cr2O3) by the healing and annealing of indentation cracks are more equiaxed than similar cavities in sapphire. Surface energies for the observed facet planes (R, S, and A) relative to the surface energy of the basal plane, C, were A/C = 1.00 0.03, R/C = 1.05 0.07 and S/C = 1.02 0.04, with the uncertainty representing 95% confidence limits. Unlike sapphire, P-plane facets were not observed. The substantial rounding of the cavities in ruby indicated that portions of the Wulff shape were above the roughening transition temperature. Thus, even though Cr2O3 and Al2O3 form ideal solutions, Cr+3 ions are sufficiently surface active to modify the relative free energy of the surfaces.

Citation

Journal of the American Ceramic Society

Volume

85

Issue

No. 7

Pub Type

Journals

Keywords

cavities, equilibrium shape, ruby, surface energies, Wulff shape

Citation

Choi, J. , Kim, D. , Hockey, B. , Wiederhorn, S. , Blendell, J. and Handwerker, C. (2002), Equilibrium Shape of Internal Cavities in Ruby and the Effect of Surface Energy Anistropy on the Equilibrium Shape, Journal of the American Ceramic Society (Accessed October 11, 2025)