Journal of the european ceramic society vol:27 issue:2-3 pages:1805-1809
This work presents the most important aspects of the devitrification behaviour of a barium magnesium aluminosilicate (BMAS) glass-ceramic with the Ba-osumilite stoichiometry. The melt-derived BMAS glass-ceramic was first pulverised and subsequently hot pressed to produce sintered powder compacts, some of which were subjected to post-sintering heat treatments in air. The BMAS glass devitrification behaviour was studied by means of scanning electron microscopy (SEM), electron probe microanalysis (EPMA), transmission electron microscopy (TEM), and X-ray diffraction (XRD). This study revealed that at temperatures < 1000 degrees C, the BMAS glass crystallisation yielded several metastable crystalline phases (i.e. celsian, hexacelsian, alpha/beta-cordierite, andP-quartz,s) instead of the thermodynamically stable Ba-osumilite. On the other hand, annealing of the BMAS glass at temperatures >= 1000 degrees C caused the transformation of all metastable phases to Ba-osumilite. Understanding the crystallisation behaviour of the BMAS glass-ceramic is essential in order to use this material as matrix in fibre-reinforced composites suitable for high-temperature structural applications. (c) 2006 Elsevier Ltd. All rights reserved.