Sol-gel quaternary reactive powders in the pseudo-ternary MgO•Al2O3-Al2O3•TiO2-3Al2O3•2SiO2 system

Quaternary reactive oxide powders in the pseudo-ternary system MgO.Al2O3-Al2O3.TiO2- 3Al(2)O(3).2SiO(2), have been obtained using sol-gel method, alkoxide route, by simultaneous gelation of all four cations. The powders were characterised, comparatively with ternary sol-gel powders from Al2O3-TiO2-MgO and Al2O3-TiO2-SiO2 systems, previously reported, by the following methods: XRD, IR spectroscopy, DTA/TGA, TEM, EDAX and BET specific surface area measurements. In the selected experimental conditions, amorphous, and nano-sized powders have been prepared. The formation of M-O-M'-O-M" bonds in solution, during the preparation of samples, has been evidenced. The large value of the specific surface area and the great tendency of crystallisation underlines the high reactivity of these powders. The powders were tested as precursors for nanocrystalline ceramics preparation of tialite (Al2TiO5) type.