The crystallization of stoichiometric barium osumilite (BaMg 2 Al 6 Si 9 O 30 ) glass manufactured by melting or by sol-gel processing using an all-alkoxide route (AAR) or a partial-alkoxide route (PAR) using mixed alkoxides and salts has been characterized by thermal methods, phase analysis, and microstructural analysis. In all glasses, crystallization with heat treatment at a finite heating rate (1 or 10 K/min) occurs via an initial phase separation, leading to regions devoid of and enriched in BaO. In PAR gel glass and melt glass, the BaO-deficient regions crystallize as µ-cordierite, but they appear to remain amorphous in AAR gel glass, in which hexacelsian is the first phase, to crystallize at the interface between the phase-separated regions. With further heat treatment, barium osumilite becomes the dominant phase. Crystallization with isothermal heat treatment at 1250°C leads to direct crystallization of barium osumilite in bulk and powder samples of melt glass, but not in bulk and powder samples of sol-gel glass, which again form precursor phases, such as µ-cordierite, ␣-cordierite, hexacelsian, and mullite. The crystallization mechanisms and morphologies are discussed here.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.