%0 Journal Article
%T ETUDE DE LA DEVITRIFICATION DES VERRES FLUOREES A BASE DE MAGNESIUM
%A C. Benhamideche
%A A. Boutarfaia
%A M. Poulain
%J Journal of Fundamental and Applied Sciences
%D 2013
%I El Oued University
%X The kinetics of devitrification of fluoride glasses stabilized by magnesium fluoride when heated for some time between the glass transition and melting temperatures. The crystallization kinetics of AlF3-YF3-PbF2-CdF2-MgF2 glass prepared by melting the halide powders were studied by differential scanning calorimetry (DSC). The heating rate varied between 2 and 10 Kmim-1. Arami¡¯s exponent (n) obtained by a non-isothermal method was 1.5 and 2.5 for a AlF3-YF3-PbF2-CdF2-xMgF2 (x= 0, 5, 10) and n > 2.5 for a AlF3-YF3-PbF2-CdF2-15MgF2. According to the classical interpretation of n, these magnitudes correspond to diffusion controlled growth of crystals. The activation energies for crystallization, (E), varied from 195-326 KJ/mol. These results confirm the improved stability of these glasses, which could be used as base glasses for low phonon energy fluoride glass fibers.
%K crystallization kinetics
%K glass transition
%K DSC
%K Avrami¡¯s exponent (n)
%K activation energies (E).
%U http://www.jfas.info/index.php/JFAS/article/view/134/pdf