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Early Stages of Crystallization in Canasite‐Based Glass Ceramics
Author(s) -
Kanchanarat Naruporn,
Miller Cheryl A.,
Hatton Paul V.,
James Peter F.,
Reaney Ian M.
Publication year - 2005
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.1551-2916.2005.00589.x
Subject(s) - nucleation , fluorapatite , crystallization , materials science , transmission electron microscopy , chemical engineering , ceramic , stoichiometry , phase (matter) , supercooling , crystallography , mineralogy , apatite , composite material , nanotechnology , chemistry , thermodynamics , organic chemistry , physics , engineering
Previous work by Miller et al . (2000–2004) has demonstrated that canasite‐based glass ceramics have potential for use as biocompatible glass ceramics in hard‐tissue augmentation. Several compositional modifications with respect to the stoichiometric formula (K 2 Na 4 Ca 5 Si 12 O 30 F 4 ) were studied and biocompatibility in simulated body fluid was reported. However, the mechanism(s) of crystallization were not investigated in detail. The purpose of this study was to examine the early stages of nucleation and growth in four glass compositions using X‐ray diffraction and transmission electron microscopy. In stoichiometric compositions (CAN1), laths of predominantly frankamenite homogeneously nucleate throughout the glass at ∼700°C without the presence of a nucleating phase. However, in Na 2 O‐deficient compositions (CAN2), CaF 2 particles (650°C) act as nucleating sites for canasite laths (700°C). In CaO‐rich compositions (CAN3), CaF 2 particles (650°C) once again act as nucleating sites but for xonotlite (700°C) rather than canasite laths. Instead, frankamenite and canasite crystallize to become the dominant phases at >700°C. In P 2 O 5 ‐modified compositions (CAN4), CaF 2 and fluorapatite, present on cooling, act as nucleating agents for canasite (750°C).