Preparation and characterization of a powder precursor, consisting of oxides of Li–Al–Si in the form of hydroxyhydrogel for synthesis of β-spodumene ceramics

Powder precursors of different compositions in the system Li2O–Al2O3–SiO2 were prepared in the hydroxy-hydrogel form by wet interaction technique in aqueous medium for ultimate synthesis of low expansion ceramics. Properly processed powder precursors were characterized. It was found that the powder precursor produced by this process was in meta-stable state with the aluminium in the tetrahedral as well as in the octahedral co-ordination sites. The confirmation of this finding was made by IR analysis of the prepared powder precursors as well as the heat treated samples. It was further found that the complete dehydroxylation did not occur even after heat treatment at 700 °C. The XRD analysis of the samples, when heat treated at 700 °C confirmed the detection of β-spodumene phase and the formation of this phase was almost complete when the samples were heat treated at 1000 °C.