Journal of Materials Research


Initial stages of silicate growth on and oxidation of graphite: A model for composites

Dawn A. Bonnella1, Darrin Jirona1 and Timothy Flinna1

a1 Department of Materials Science and Engineering, The University of Pennsylvania, Philadelphia, Pennsylvania 19104

The initial stages of silicate growth on graphite are characterized with atomic force microscopy. The morphological development indicates that decomposition of tetra ethyloxysilane at low pressure produces films of 3 nm clusters located at undercoordinated carbon sites. Clusters eventually cover the surface, at which point a second layer grows. In higher pressure deposition multiple layers of clusters grow simultaneously. A comparison of the oxidation behavior of surfaces with defects completely and incompletely terminated with SiOx shows that edge recession is the primary oxidation mechanism and that the site specificity of SiOx is effective in inhibiting oxidation.

(Received October 12 1995)

(Accepted June 15 1997)