METHOD FOR PRODUCING A COMPOSITE MATERIAL WITH A CARBIDE MATRIX
A method of densifying a porous substrate with a matrix, includes subdividing the pores present in the porous substrate so as to form in the substrate a network of micropores, the subdividing being performed with a filler composition comprising at least one carbon-containing phase or carbide-containing phase that is accessible via the network of micropores; and infiltrating the network of micropores formed by the filler material by reactive chemical vapor infiltration, the infiltration being performed with a reactive gas composition that does not contain carbon and that includes at least one element suitable for reacting with the carbon of the filler composition in order to form a carbide.
1 . A method of densifying a porous substrate with a matrix, said method comprising:
subdividing the pores present in the porous substrate so as to form in said substrate a network of micropores, said subdividing being performed with a filler composition comprising at least one carbon-containing phase or carbide-containing phase that is accessible via the network of micropores; and
infiltrating the network of micropores formed by the filler material by reactive chemical vapor infiltration, the infiltration being performed with a reactive gas composition that does not contain carbon and that includes at least one element suitable for reacting with the carbon of the filler composition in order to form a carbide.
2 . A method according to claim 1 , further comprising making a fiber structure corresponding to the porous substrate that is to be densified.
3 . A method according to claim 2 , wherein the fiber structure is made from carbon 25 fibers or from silicon carbide fibers.
4 . A method according to claim 1 , wherein the subdividing of the pores comprises introducing a powder into the porous substrate, the powder being constituted by micrometer or submicrometer particles of carbon-containing or carbide-containing material, or including at least a surface layer of carbon-containing or carbide-containing material.
5 . A method according to claim 1 , wherein the subdividing of the pores comprises impregnating the porous substrate with a liquid precursor for carbon or carbide, or for a carbon-containing or carbide-containing material, and transforming the precursor by pyrolysis.
6 . A method according to claim 1 , wherein the subdividing of the pores comprises forming in the porous substrate an aerogel or xerogel of a precursor material for carbon or carbide or for a carbon-containing or carbide-containing material, and transforming the precursor by pyrolysis.
7 . A method according to claim 1 , wherein the reactive gas composition comprises at least one of the reactive elements selected from: titanium, zirconium, hafnium, tantalum, silicon, and boron.
8 . A method according to claim 7 , wherein the reactive gas composition comprises at least one halide gas selected from at least: TiCl 4 , ZrCl 4 , HfCl 4 , SiH 4 , TaI 4 , TaCl 5 , SiCl 4 , BCl 3 , and BF 3 .
9 . A method according to claim 1 , wherein the reactive chemical vapor infiltration is performed under pulsed pressure.
10 . A method according to claim 2 , wherein prior to subdividing the pores, the method comprises forming a layer of a carbide or of pyrolytic carbon on the fibers of the fiber structure.
11 . A method according to claim 10 , further comprising forming a layer of nitride having no carbon on the layer of carbide or of pyrolytic carbon formed on the fibers of the fiber structure.