| 摘要 |
A composite carbon-carbon article adapted for resisting a degradation due to the surrounding medium at elevated temperatures. This article comprises a carbon-carbon composite substrate to which a coating has been applied, comprising an inner layer of SiC produced by a conversion process where Si is diffused into the carbon substrate, and an outer layer of Si3N4 applied by chemical vapour deposition. Such a coating provides an exceptional resistance to oxidation at 1371 DEG C and above, in the case of carbon-carbon materials. Optionally, preliminary SiC coatings applied by the chemical vapour deposition process or of pyrolytic graphite can be applied before the application of the inner SiC layer. The invention applies particularly for the manufacture of articles employed in the aerospace industry. <IMAGE>
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