Effect of Composition on Microstructural Development in MgO–Al ₂ O ₃ –SiO ₂ Glass‐Ceramics

Abstract

The transformation kinetics and microstructures of glass‐ceramics, which deviate from those of a stoichiometric cordierite compound, are greatly dependent on the compositions of the starting glasses. Compositions richer in (MgO,SiO 2 ) than the stoichiometric cordierite compound suppress the formation of μ‐cordierite, yet enhance the crystallization of α‐cordierite, resulting in a higher content of α‐cordierite. In contrast, compositions richer in Al 2 O 3 than the stoichiometric cordierite compound have no effect on the crystallization of α‐cordierite. Thus, most of the glass crystallizes to μ‐cordierite in the initial stage, followed by the slow transformation of μ‐cordierite into an α‐phase, which results in a low content of α‐cordierite.