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Crystallization Kinetics of LaF 3 Nanocrystals in an Oxyfluoride Glass
Author(s) -
de PablosMartín Araceli,
Hémono Nicolas,
Mather Glenn C.,
Bhattacharyya Sommnath,
Höche Thomas,
Bornhöft Hansjörg,
Deubener Joachim,
Muñoz Francisco,
Durán Alicia,
Pascual Maria J.
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2011.04547.x
Subject(s) - crystallization , materials science , differential scanning calorimetry , crystal (programming language) , transmission electron microscopy , glass transition , crystal growth , nanocrystal , phase (matter) , mineralogy , chemical engineering , crystallography , analytical chemistry (journal) , chemistry , composite material , thermodynamics , nanotechnology , polymer , chromatography , physics , engineering , organic chemistry , computer science , programming language
Nanocrystallization of LaF 3 in a glass of composition 55SiO 2 –20Al 2 O 3 –15Na 2 O–10LaF 3 (mol%) has been achieved by heat treatment above the glass transition temperature. A maximum crystal size of 14 nm has been attained, with the crystalline fraction and crystal size dependent on the time and temperature of thermal treatment. The effect of lanthanum fluoride crystallization is noticeable from the microstructural and compositional changes in the glass matrix, which have been studied using several techniques, including viscosity, dilatometry, X‐ray diffraction, and quantitative Rietveld refinement, transmission electron microscopy, and differential scanning calorimetry. The crystallization mechanism is shown to occur via regions of La‐ and Si‐phase separation in the glass, from which the fluoride crystals develop during heat treatment. The interface between the glass matrix and the crystals in the demixed ranges is enriched in network formers, mainly SiO 2 , creating a viscous barrier, which inhibits further crystal growth and limits the crystal size to the nanometric range.