W. Winter et al., TEM INVESTIGATION OF CORDIERITE CRYSTALLIZATION FROM A GLASS POWDER WITH COMPOSITION MG2AL4SI11O30, Journal of the European Ceramic Society, 15(1), 1995, pp. 65-70
The crystallization of a glass powder with composition Mg2Al4Si11O30 t
o beta-quartz(ss) and the transformation of beta-quartz(ss) to alpha-c
ordierite were investigated by means of SEM and TEM. Crystallization o
f beta-quartz(ss) starts at the surfaces of the glass grains. At first
growth proceeds nearly isotropically, but due to mutual hindrance gro
wth perpendicular to the surface is preferred when the beta-quartz(ss)
crystals impinge on each other. Tile transformation of beta-quartz(ss
) to cordierite starts at the surfaces of the beta-quartz(ss) crystals
. In a first stage the cordierite nuclei grow over long distances only
along the grain boundaries of several beta-quartz(ss) crystals. On pr
olonged annealing the cordierite rims grow dendritically, into the cor
es of beta-quartz(ss), maintaining the same crystallographic orientati
on.