On the faceting of ceramic surfaces

A model is proposed by which ceramic surfaces change from flat vicinal surfaces into those of a faceted hill-and-valley structure. This model is based on scanning electron microscopy, transmission electron microscopy and atomic-force microscopy observations of facet formation on annealed ( 10 10 ) α-alumina surfaces. The progression of surface faceting starts with the nucleation and growth of an individual facet. The growth of this facet creates local surface disturbances that promote the nucleation of adjacent facets; thus, domains of faceted surface form on the otherwise smooth surface. Through time, these domains coalesce and the facets coarsen into the final hill-and-valley morphology.