Small‐angle X‐ray scattering study of cordierite sol–gel synthesis

摘要: The structure of ceramic materials in the size range a few nanometres to tens is closely related structural features precursor. Here nanostructural development cordierite (2MgO–2Al2O3–5SiO2) material studied by SAXS during its processing sol-gel route. Homogeneous alcogels were prepared at 298 K hydrolysis – condensation mixture made Si(OC2H5)4, sec-Al(OC4H9)3, Mg(NO3)2, water and alcohol. polymeric nature mechanism evidenced. final internal particles depend on quantity used for hydrolysis. In gel state, 7 or 8 nm exhibiting mass fractal with D = 1.9 are observed. Xerogels resulting from classical drying powdered. Firing pellets leads porous solids. small-angle scattered intensity grows strongly Porod plot shows linear behaviour slope −3.5. Sintering full density very difficult. Aerogels obtained supercritical consist primary homogeneous units about 2 nm size, attached into volume aggregates (D 1.8). aerogels exhibit dramatically improved sintering ability. Full dense glasses temperatures less than 1273 K fine-grained glass ceramics without any nucleating agent.