Thermal and Structural Characterization of Transparent Rare-Earth Doped Lead Fluoride Glass-Ceramics

• 作者: Chaouki Bensalem Daniel Vivien Gilles Patriarche Madjid Diaf Michel Mortier Patrick Gredin
• 来源期刊: 玻璃与陶瓷期刊(英文)
• 学科: 化学
• 关键词: GLASS-CERAMIC RARE-EARTH THERMAL Analysis DEVITRIFICATION NANOCRYSTALLITE X-Ray Diffraction
• 年，卷（期）: 2012,（2）
• 页码范围: 65-74
• 页数: 10页
• 分类号: O6

摘要

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.