Societe Europeenne De Propulsion

Marc Lacoste

Jacques Thebault

Michel Laxague

Alain Nale

The method comprises forming a coating on the product of composite material to be protected. The coating contains a mixture of a non-oxide refractory ceramic in finely-divided form, at least one refractory oxide in finely-divided form and providing healing properties by forming a glass, and a binder constituted by a polymer that is a precursor of a non-oxide refractory ceramic. The polymer is transformed into a ceramic to obtain a protective layer comprising a non-oxide refractory ceramic phase and a healing phase which together constitute two interpenetrating lattices. After the ceramic precursor polymer has been transformed, a final heat treatment step may be performed at a temperature higher than the softening or melting temperature of the healing phase.

Method of protecting products of composite material against oxidizing

Anti-oxidation protection for a silicon compound under both an active oxidation condition and a passive oxidation condition is achieved by forming an intermediate layer devoid of the element silicon between the surface of the silicon compound ceramic, such as SiC, and a silica based vitreous outer layer, such as SiO.sub.2, to be subsequently deposited. The intermediate layer is made of alumina (Al.sub.2 O.sub.3) or an alumina precursor, so as to constitute a reaction barrier between the silicon compound and the silica outer layer on the one hand, and trap any amount of silica that may be formed by an oxidation of the silicon compound.

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Villenave D'Ornon, France

Marc Lacoste