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Crystallization in a Barium‐Containing Magnesium Aluminosilicate Glass‐Ceramic
Author(s) -
Chaim Rachman,
Heuer Arthur H.
Publication year - 1992
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1992.tb04218.x
Subject(s) - crystallization , cordierite , nucleation , materials science , mineralogy , aluminosilicate , chemical engineering , silicate , glass ceramic , cristobalite , annealing (glass) , ceramic , analytical chemistry (journal) , quartz , composite material , chemistry , biochemistry , organic chemistry , engineering , catalysis , chromatography
Crystallization in a Ba‐containing magnesium aluminosilicate (Ba‐MAS) glass‐ceramic was studied using transmission electron microscopy. Ba‐MAS slabs were hot‐pressed at 1000°C to form dense glassy bodies, which were crystallized by further heating in air or argon between 850° and 1300°C. Heterogeneous nucleation of a metastable highquartz solid solution (μ‐cordierite) occurred at crystallization temperatures below 1100°C, followed by dendritic growth; the interdendrite phase was Ba‐rich silicate glass. The high‐quartz solid solution generally acted as a precursor for the nucleation of the stable β ‐phase, which was the final crystallization product. Surprisingly, slower crystallization kinetics were observed in argon than in air. Further morphological changes at the higher temperatures and longer annealing, times resulted from a Rayleigh type instability, which led to breakup of the interdendrite silicate rods, and simultaneous polygonization of β ‐cordierite.