Abstract: A composite material containing a matrix and a fibrous reinforcement, in particular a textile embedded in the matrix. The matrix includes a geopolymer of the poly(phospho-sialate) type having the following formula I: (1) (—P—O—Si—O—Al—O—)n in which n is greater than 2. The matrix further includes zirconium covalently bonded to the matrix, especially in the —ZrO form and/or in the —O—Zr—O form. The matrix has a melting temperature greater than 700° C., especially equal to or greater than 1200° C.

Abstract: A composite material containing a matrix and a fibrous reinforcement, in particular a textile embedded in the matrix. The matrix includes a geopolymer of the poly(phospho-sialate) type having the following formula I: (1) (—P—O—Si—O—Al—O—)n in which n is greater than 2. The matrix further includes zirconium covalently bonded to the matrix, especially in the —ZrO form and/or in the —O—Zr—O form. The matrix has a melting temperature greater than 700° C., especially equal to or greater than 1200° C.

Abstract: A matrix for a thermostructural fibrous composite material obtained by geopolymer synthesis based on nanocrystalline cristobalite resulting from the crystallization of geopolymer micelles of potassium polysiloxonate K—(Si—O—Si—O)n. The nanocrystalline cristobalite is in the form of micelles and/or microspheres having dimensions of less than 1 micron, preferably of less than 500 nanometers, connected together by an amorphous phase. The matrix contains at least 85 percent by weight of oxide SiO2 with at most 15%, preferably at most 10%, by weight of alkali metal oxide K2O. The nanocrystalline cristobalite results from the crystallization of geopolymer micelles of potassium polysiloxonate by a heat treatment at a temperature preferably between 600° C. and 800° C., for a time of less than 30 minutes. The fibrous composite material impregnated with this matrix is thermostructural.

Abstract: A matrix for a thermostructural fibrous composite material obtained by geopolymer synthesis based on nanocrystalline cristobalite resulting from the crystallization of geopolymer micelles of potassium polysiloxonate K—(Si—O—Si—O)n. The nanocrystalline cristobalite is in the form of micelles and/or microspheres having dimensions of less than 1 micron, preferably of less than 500 nanometers, connected together by an amorphous phase. The matrix 4 contains at least 85 percent by weight of oxide SiO2 with at most 15%, preferably at most 10%, by weight of alkali metal oxide K2O. The nanocrystalline cristobalite results from the crystallization of geopolymer micelles of potassium polysiloxonate by a heat treatment at a temperature preferably between 600° C. and 800° C., for a time of less than 30 minutes. The fibrous composite material impregnated with this matrix is thermostructural.

Abstract: A composite material resistant to high temperatures including at least one layer of a fibrous textile reinforcement composed of metallic fibers of a diameter smaller than about 30 microns, and a thermosetting ceramic matrix impregnating the fibrous textile reinforcement, which matrix is based on a sialate or polysialate resin.

Abstract: An alkali aluminosilicate geopolymeric matrix for the production of composite materials with a fiber reinforcement has a composition, after dehydration, expressed as oxides, as follows:yM.sub.2 O:Al.sub.2 O.sub.3 :xSiO.sub.2where "x" is 6.5-70, "y" is 0.95-9.50 and M is Na, K or Na+K. The geopolymeric matrix comprises a nanocomposite material with at least two phases, with (a) a first nodular silicious phase composed of nanospheres with diameters of less than 1 micron, preferably less than 500 nm, and (b) a second polymeric phase essentially composed of alkali poly(aluminosilicate) having one or more sialate bridge (--Si--O--Al--O) cross-linking sites of total formula M.sub.4 Si.sub.2 AlO.sub.10 to M.sub.2 Si.sub.4 AlO.sub.16, such that, in the alkali poly(aluminosilicate), the ratio of Si(O.sub.4) to Al(O.sub.4) is >3.5, preferably >5. The geopolymeric matrix has a spectrum of .sup.29 Si MASNMR with three resonance regions: -87.+-.5 ppm, -98 .+-.5 ppm, -107 .+-.

Abstract: A geopolymeric fluoro-alumino-silicate binder is provided which makes it possible to manufacture items with excellent mechanical and heat resistance at temperatures between 250.degree. C. and 650.degree. C. with a variable coefficient of thermal expansion 5.10-6/.degree.C.<.DELTA..lambda.<35.10.sup.-6 /.degree.C. After curing, the geopolymeric compound thus obtained is a solid solution comprising:a) a geopolymer of the fluoro-alkaline poly(sialate-disiloxo) type (M,F)-PSDS of formula ##STR1## b) an alkaline-alumino-fluoride M.sub.3 A1F.sub.6 such as elpasolite K.sub.2 NaAlF.sub.6 ;c) a silicious phase SiO.sub.2 of the Opal CT type, hydrous SiO.sub.2 ;where "M" represents the cations Na and/or K, and "n" the degree of polymerisation.The process for obtaining fluoro-alumino-silicate geopolymer binders consists of reacting a geopolymeric resin obtained from a reactional mixture containing:a) an aqueous solution of alkaline silicate with a molar ratio M.sub.2 O:SiO.sub.2 comprised between or equal toM.sub.

Abstract: A composite ceramic-ceramic material is disclosed having a fibrous reinforcing ceramic and a ceramic matrix made of a geopolymeric compound containing:(a) a poly(sialate) geopolymer M.sub.n (--Si--O--Al--O--).sub.n and/or poly(sialate-siloxo) M.sub.n (--Si--O--Al--O--Si--O--).sub.n, M representing at least one alkaline cation, and n the degree of polymerization;(b) ultrafine silicious and/or aluminous and/or silico-aluminous constituents, of size smaller than 5 microns, preferably lower than 2 microns,the said geopolymeric compound being obtained by polycondensation at a temperature between 20.degree. C. and 120.degree. C. of an alkaline alumino-silicate reaction mixture, the composition of the principal constituents of the said geopolymeric compound expressed in terms of mole ratios of the oxides being between or equal to following values:M.sub.2 O/SiO.sub.2 --0.10 TO 0.95,SiO.sub.2 /Al.sub.2 O.sub.3 --2.50 TO 6.00,M.sub.2 O/Al.sub.2 O.sub.3 --0.25 TO 5.70,M.sub.2 O representing either Na.sub.2 O and/or K.