engleski

Crystallization studies of cordierite originated from sol-gel precursors

Detailed studies of the crystallization behavior of two sol-gel derived precursors of cordierite have been made by differential scanning calorimetry (RT-1350^oC) and in-situ high temperature X-ray diffraction from RT up to 1165^oC. Powder precursors were prepared using tetraetoxysilane (TEOS), Mg(NO_3)_2&middot ; 6H_2O and two different aluminum sources, Al-sec-butoxide (for precursor BC) and Al(NO_3)_3&middot ; 9H_2O (for precursor NC). The Rietveld method was performed for quantitative phase analysis of the crystallization products and for refinement of their crystal structures. It was found that crystallization occurred at ~800^oC for both precursors. For precursor BC crystallization involves the appearance of stuffed derivative of beta-quartz (containing Mg and Al), alpha-cordierite, mullite and enstatite, while for precursor NC it involves the formation of stuffed derivative of beta-quartz, sapphirine, mullite, alpha-cordierite and beta-cristobalite.

cordierite; stuffed derivatives of quartz; high temperature XRD; Rietveld structure refinement; DSC

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