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Compositional effects on the crosslink density of Ca–(Mg)–(Y)–Si–Al–oxyfluoronitride glasses
Author(s) -
Clausell Carolina,
Barba Antonio,
Jarque Juan Carlos,
GarcíaBellés Ángel R.,
Pomeroy Michael J.,
Hampshire Stuart
Publication year - 2018
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/jace.15210
Subject(s) - fluorine , molar volume , yttrium , aluminosilicate , softening point , glass transition , mineralogy , materials science , thermal expansion , analytical chemistry (journal) , nitrogen , indentation hardness , inorganic chemistry , chemistry , thermodynamics , metallurgy , composite material , oxide , organic chemistry , microstructure , physics , polymer , catalysis
The effects of fluorine and nitrogen substitution for oxygen in aluminosilicate glasses, effectively oxyfluoronitride ( OFN ) glasses, modified by calcium, calcium–yttrium or calcium–magnesium on thermal and physical/mechanical properties have been compared. Thus, 42 glasses in the Ca–(Mg)–(Y)–Si–Al–O–(N)–(F) system have been prepared and characterized with respect to density ( ρ ), molar volume ( MV ), compactness (C), free volume ( FV ), glass transition temperatures measured by DTA (T g, DTA ) and dilatometry (T g,dil ), dilatometric softening point ( T DS ), microhardness (μHv) and Young's modulus (E). Gradients of property variation with nitrogen or fluorine substitutions for oxygen are similar for all three different oxyfluoronitride glass systems and are comparable with those reported for other OFN glasses, again indicating independent and additive effects of nitrogen and fluorine. In attempting to further understand how fluorine affects the cross‐link density ( CLD ) in OFN glasses, it becomes apparent that it is necessary to allow for a greater contribution by aluminum in a modifier role as fluorine content is increased. This modified calculation of CLD values results in good linear fits between T g and CLD values. This analysis clearly demonstrates and endorses the concepts that thermal properties are related to CLD while physical/mechanical properties are dependent on glass compactness.