摘要:
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.2 where "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 .+-.5 ppm, and prevents the oxidation at high temperatures of the carbon fibre. The resulting composite materials can be used at temperatures of up to 1000.degree. C.
摘要:
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.sub.2 O, or a mixture of at least one alkaline oxide with CaO.The fibrous reinforcement consists of ceramic fibres such as SiC, Al.sub.2 O.sub.3, SiO.sub.2, glass, carbon. The addition of alkaline sulphides and alkaline sulphites enables glass fibres to be protected against chemical attack due to the alkalinity of the matrix.
摘要翻译:PCT No.PCT / FR87 / 00396 Sec。 371日期:1988年6月10日 102(e)1988年6月10日PCT PCT日期:1987年10月13日PCT公布。 第WO88 / 02741号公报 公开了一种复合陶瓷陶瓷材料,其具有纤维增强陶瓷和由地质聚合物制成的陶瓷基体,所述地质聚合物包含:(a)聚(唾液酸酯)地质聚合物Mn(-Si-O-Al-O - )n和/或聚(唾液酸酯-Siloxo)Mn(-Si-O-Al-O-Si-O-)n,M表示至少一种碱性阳离子,n表示聚合度; (b)尺寸小于5微米,优选低于2微米的超细硅质和/或铝和/或硅铝质组分,所述地质聚合物通过在20℃至120℃的温度下缩聚得到 的碱性铝硅酸盐反应混合物,所述地质聚合物的主要成分的组成以氧化物的摩尔比表示,其摩尔比在以下值之间或之下:M 2 O / SiO 2 -0.10至0.95,SiO 2 / Al 2 O 3 - 2.50至6.00,M 2 O / Al 2 O 3 -0.25至5.70,代表Na 2 O和/或K 2 O的M 2 O,或至少一种碱性氧化物与CaO的混合物。 纤维增强材料由诸如SiC,Al2O3,SiO2,玻璃,碳等陶瓷纤维组成。 碱性硫化物和碱性亚硫酸盐的添加使玻璃纤维得以保护,防止由于基质的碱度引起的化学侵蚀。
摘要:
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.
摘要:
The geopolymeric alumino-silicates have been grouped in three families depending on the atomic ratio Si/Al which may be 1, 2 or 3. With the most commonly used simplified notation, a distinction is made between______________________________________ poly M.sub.n --(Si--O--Al--O) .sub.n-- or (M)--PS, (sialate) poly M.sub.n --(Si--O--Al--O--Si--O) .sub.n-- or (M)--PSS, (sialate- siloxo) poly M.sub.n --(Si--O--Al--O--Si--O--Si--O) .sub.n-- or (sialate- (M)--PSDS disiloxo). ______________________________________ A process for obtaining a geopolymer of the alkaline poly(sialate-disiloxo) family (M)-PSDS with the ratio Si/Al=3 involves producing geopolymeric resin obtained from a reactional mixture containing:a) an aqueous solution of alkaline silicate with a molar ratio SiO.sub.2 :M.sub.2 O comprised between or equal to SiO.sub.2 :M.sub.2 O 4.0:1 and 6.6:1 the concentration of which is over 60% wt and where the initial viscosity at 20.degree. C. is 200 centipoises, then increases but does not exceed 500 centipoises before 5 hours at 20.degree. C.;b) an alumino-silicate oxide (Si.sub.2 O.sub.5,Al.sub.2 O.sub.2) in which the Al cation is in coordination (IV-V), as determined by the MAS-NMR spectrum for .sup.27 Al, the said oxide being in such a quantity that the molar ratio Al.sub.2 O.sub.3 :SiO.sub.2 is comprised between or equal to Al.sub.2 O.sub.3 :SiO.sub.2 1:5.5 and 1:6.5, and then allowing the geopolymeric resin to cure.As against the prior art, the fact that there is no need to add fillers to prevent the geopolymeric matrix from cracking makes it possible to keep a very low viscosity in the geopolymeric resin and develop its film-forming property, which is a distinct advantage when fibers or other granular materials are to be impregnated.