TITLE:
Thermal and Structural Characterization of Transparent Rare-Earth Doped Lead Fluoride Glass-Ceramics
AUTHORS:
Chaouki Bensalem, Michel Mortier, Daniel Vivien, Patrick Gredin, Gilles Patriarche, Madjid Diaf
KEYWORDS:
Glass-Ceramic; Rare-Earth; Thermal Analysis; Devitrification; Nanocrystallite; X-Ray Diffraction
JOURNAL NAME:
New Journal of Glass and Ceramics,
Vol.2 No.2,
April
23,
2012
ABSTRACT: The devitrification of glasses with composition 50GeO2-40PbO-10PbF2-xREF3, RE = Gd, Eu, 0 3+: β-PbF2 nanocrystals embedded in a glassy oxide matrix. This transformation is investigated using thermal analysis, X-ray diffraction and electron microscopy. A comparison with RE3+: β-PbF2 ceramics prepared by standard ceramic techniques is performed. The Rare Earth cations show a strong nucleating effect for the precipitation of the RE3++: β-PbF2 nanocrystals. The evolution of the unit cell parameters of the REF3: β-PbF2 solid solution results from a combined effect of Pb2+-RE3+ substitution and interstitial F– introduction. In the glass ceramics, RE3+: β-PbF2 nanocrystals are constrained by the glassy matrix when they form with a pressure equivalent to 1.6 GPa. The constrained nanocrystals can return to a relaxed state by chemical dissolution of the embedding glassy matrix, followed by thermal treatments.