Espectroscopia vibracional das fases cristalográficas da mulita em função do trattamento térmico

Abstract

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A theoric model to obtain the vibrational energies of mullite (3Al2O3∙2SiO2) based on the subdivision of the crystalline structure in basic units of symetry AlO4, SiO4 and AlO6 is presented. The crystallografic phase evolution of mullite (3Al2O3∙2SiO2) prepared from polimeric and colloidal gels is studied as a function of the thermal treatment. Shifts and bands formation which occur in the infrared range of the absorption spectrum confirm the change in coordination of Si and Al atoms as the mullite orthorrombic structure is established.