Non-Isothermal Crystallization Kinetics and Phase Transformation of Bi2O3-Sio2 Glass-Ceramics
2011
The Bi2O3-SiO2 (BS) glass-ceramics were prepared by melt-quench technique,
and the crystallization kinetics and phase transformation behavior were
investigated in accordance with Kissinger and Johson-Mehl-Avrami equation,
DSC, XRD and SEM. The results show that in the heat treatment process (or
termed as re-crystallizing process) Bi2SiO5 and Bi4Si3O12 crystals were found
consequently. Respectively, the crystallization activation energies of the
two crystals are Ep1=14.8kJ/mol and Ep2=34.1kJ/mol. And the average
crystallization index of n1=1.73 and n2=1.38 suggested volume nucleation,
one-dimensional growth and surface nucleation, one-dimensional growth from
surface to the inside respectively. The meta-stable needle-like Bi2SiO5
crystals are easily to be transformed into stable prismatic Bi4Si3O12
crystals. By quenching the melt and hold in 850°C for 1h, the homogenous
single Bi4Si3O12 crystals were found in the polycrystalline phase of the BS
glassceramics system.
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