Formation of a Metastable Celsian-Cordierite Eutectic Structure During the Crystallization of a Ba-Osumilite Glass–Ceramic


  • L. Pickney—contributing editor

  • Supported by the European Commission under Grant No. BRE2-CT93-3004, and the K.U. Leuven Research Council under Grant No. DB/97/26.

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This work addresses the formation conditions and stability of a celsian-cordierite eutectic structure produced during the crystallization of a barium magnesium aluminosilicate (BMAS) glass–ceramic with the Ba-osumilite stoichiometry. The melt-derived BMAS glass–ceramic was pulverized and subsequently hot pressed to produce sintered powder compacts, some of which were subjected to post-sintering heat treatments in air. The study of the devitrified BMAS glass revealed that a metastable celsian-cordierite eutectic structure resulted from the prolonged annealing of the BMAS glass–ceramic between 860° and 1000°C. The celsian-cordierite eutectic structure transformed to the thermodynamically stable Ba-osumilite phase when annealed at temperatures >1000°C.