DEWETTING OF GLASS-COATED ALPHA-AL2O3 (10(1)OVER-BAR-0) SURFACE

Anisotropy in the wetting behaviour of a silicate liquid in contact wi th the faceted sapphire {10 (1) over bar 0} surface has been demonstra ted using a simple specimen geometry. The shape of the glass pockets i s influenced by the asymmetric faceting of the alpha-Al2O3 {10 (1) ove r bar 0} surface. The glass remains preferentially in contact with the {(1) over bar 012} facets in alpha-Al2O3. Using this approach, which allows control over temperature and composition of the glass, a sequen tial study of the mechanisms of solution-precipitation and facet growt h is possible.