J. Phys. Colloques
Volume 50, Numéro C5, Mai 1989Actes de la 7ème Conférence Européenne sur les Dépôts Chimiques en Phase Gazeuse / Proceedings of the Seventh European Conference on Chemical Vapour Deposition
|Page(s)||C5-434 - C5-434|
J. Phys. Colloques 50 (1989) C5-434-C5-434
MORPHOLOGICAL ASPECTS OF SILICON CARBIDE CHEMICALLY VAPOR-DEPOSITED ON GRAPHITEA. PARRETTA1, A. CAMANZI1, G. GIUNTA1, V. ADONCECCHI1, P. ALESSANDRINI1 et A. MAZZARANO2
1 Eniricerche S.P.A., via E. Ramarini, 32, I-00015 Montorotondo, Rome, Italy
2 Centro Sviluppo Materiali, via di Castel Romano 100, I-00129 Rome, Italy
The morphological features of silicon carbide coatings, deposited on graphite from SiCl4, C3H8 and H2 mixtures, were investigated. Based on preliminary thermodynamic calculations, the experiments were performed at atmospheric pressure in a cold wall reactor by varying the deposition temperature TD in the 1473-1673 K range and the deposition time between 10 and 120 min. SEM examinators showed considerable differences in surface morphology depending on the process parameters. A transition from a modular to a faceted structure was observed by moving towards higher TD values. A double layer structure was detected on the thickest coatings due to a sharp columnar-microcrystalline transition. The coatings prepared at TD - 1673 K showed surface microhardness values as high as 4000 HK and an optimum capability to protect graphite substrates against oxidation at 1273 K.