Early stages of crystallisation of lithium disilicate glasses containing P2O5 - An NMR study
UNSPECIFIED (1998) Early stages of crystallisation of lithium disilicate glasses containing P2O5 - An NMR study. In: 7th International Conference on the Structure of Non-Crystalline Materials (NCM7), SEP 15-19, 1997, CAGLIARI, ITALY.Full text not available from this repository.
The Si-29 nuclear magnetic resonance (NMR) spectra of glasses with a 1:2 molar ratio of Li2O : SiO2, containing P2O5, showed contributions from Q(4), Q(3) and Q(2) species, consistent with a disproportionated binary distribution and with removal of Li+ from the silicate network. to form lithium phosphate units. Crystallisation in the 0% P2O5 glass was defected by X-ray diffraction before it was observed by nuclear magnetic resonance. The crystalline Q(3) resonance grew largely at the expense of the glassy Q(3), the amounts of glassy Q(4) and Q(2) remaining constant. The width of the crystalline Q(3) resonance is related to the formation of metastable lithium disilicate phases which are precursors to the stable lithium disilicate. The presence of glass-in-glass phase separation, undetectable by transmission electron microscopy, was inferred from the chemical shift and relaxation time of the Q(4) species. Lithium disilicate was observed at shorter limes, as the P2O5 content was increased, and lithium metasilicate was also formed in glasses containing 2% or more P2O5. Crystalline Li3PO4 was not observed prior to formation of the lithium disilicate. (C) 1998 Elsevier Science B.V. All rights reserved.
|Item Type:||Conference Item (UNSPECIFIED)|
|Subjects:||T Technology > TP Chemical technology
T Technology > TA Engineering (General). Civil engineering (General)
|Journal or Publication Title:||JOURNAL OF NON-CRYSTALLINE SOLIDS|
|Publisher:||ELSEVIER SCIENCE BV|
|Number of Pages:||7|
|Page Range:||pp. 140-146|
|Title of Event:||7th International Conference on the Structure of Non-Crystalline Materials (NCM7)|
|Location of Event:||CAGLIARI, ITALY|
|Date(s) of Event:||SEP 15-19, 1997|
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