Non-isothermal crystallization kinetics of La2CaB10O19 from glass

The non-isothermal crystallization kinetics of La2CaB10O19 (LCB) from a La2O3-CaO-B2O3 glass was studied. Differential thermal analysis methods were performed on three glass powders to obtain the kinetic parameters of LCB crystallization mechanism. The activation energies for overall crystallization (E), obtained by the methods of Kissinger and Ozawa, were in the range of 479-569 kJ/mol. Multiple (five) analysis methods were used to estimate the Avrami exponent (n), which could consequently be reduced into the single value of n=3.1 +/- 0.3. The growth morphology index (m) of LCB was corroborated by microscopy (optical and electron) images, which revealed a three dimensional growth. Energy dispersive spectroscopy confirmed that LCB is the crystallizing phase from the glass by an interface controlled mechanism. The parameters of the Johnson-Mehl-Avrami kinetic model for the analysis of LCB crystallization from glass were found to be n = m = 3. (C) 2011 Elsevier B.V. All rights reserved.