title: In situ crystallization of barium zinc silicate in glass-ceramics studied by hot stage scanning electron microscopy.
abstract: Glasses with the mol% composition 30ZnO, 10Na(2)O, 10BaO and 50SiO(2) were annealed at 700°C and 760°C ex situ as well as in situ using a hot stage scanning electron microscope (SEM). The formed crystal phase (BaZn(2)Si(2)O(7)) was proved ex situ by X-ray diffraction. Annealing the glass samples in the SEM resulted in a strong surface crystallization, which was monitored for 1 h and 21 min and 2 h and 2 min at the temperatures 700°C and 760°C, respectively. The crystal growth velocities for these two temperatures were determined from a series of micrographs. It is experimentally shown that during the course of the crystallization in this non-isochemical system, the residual glassy phase changes its composition, and hence, the crystal growth velocity depends on time. Furthermore, it is shown that the electron beam irradiation directly affects the nucleation and crystal growth velocities.
authors.affiliation: Otto-Schott-Institut, Jena University, Fraunhoferstrasse 6, Jena, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Bocker
authors.forename: Marlen
authors.initials: M
authors.lastname: Michaelis
authors.forename: Christian
authors.initials: C
authors.lastname: Rüssel