Kinetics of the solid-phase synthesis of mullite in the presence of topaz

• Published in: Refractories and industrial ceramics Vol. 46; no. 1; pp. 49 - 55
• Main Authors: Vakalova, T V, Ivanchenkov, A V, Pogrebenkov, V M
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01.01.2005
• Subjects: Fluorides; Kinetics
• ISSN: 1083-4877; 1573-9139
• DOI: 10.1007/s11148-005-0048-8

Results of a kinetic study of solid-phase interactions in stoichiometric oxide mixtures of mullite composition are reported. The mechanism of mullitisation, irrespective of the oxide form (crystalline or amorphous), is diffusive in character. Topaz added in small quantities accelerates the process through generating surface and structural imperfections and activating the diffusion of reactants owing to the assistance of gaseous fluorides released by topaz. The secondary mullite produced by thermal degradation of topaz facilitates the formation of nucleation centres for topochemical reactions and activates the mullite crystallisation.