UNSPECIFIED (1999) The structure of sodium iron silicate glass - a multi-technique approach. In: 18th International Congress of Glass, JUL 05-10, 1998, SAN FRANCISCO, CALIFORNIA.

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Abstract

Sodium iron silicate glasses of formula 0.3Na(2)O . xFe(2)O(3).(0.7-x)SiO2 (0.0 less than or equal to x less than or equal to 0.20) have been prepared by melt-quenching and their structures have been studied using X-ray photoelectron spectroscopy (XPS), neutron diffraction and Mossbauer spectroscopy. XPS of surfaces fractured in ultra-high vacuum showed the presence of both Fe2+ and Fe3+ in the glasses but the proportion of the smaller oxidation state is <20% for larger x. The O 1s spectrum can be fitted by bridging and non-bridging oxygen contributions but properties show that this description is inadequate and there are contributions from bridging oxygens, Si-O-Si, from non-bridging oxygens, Si-O Na+ and also directionally bonded Si-O-Fe. The neutron diffraction and Mossbauer data indicate that iron, irrespective of oxidation state, is 4-coordinated by oxygen. The Fe-O bond length decreases and the O-O bond length increases with increasing Fe2O3 content. Mossbauer spectroscopy confirms the predominance of the Fe3+ state in these glasses and indicates smaller Fe2+ concentrations than does XPS. possibly due to restructuring at the glass fracture surfaces examined in XPS, The effective Debye temperatures for Fe2+ and Fe3+ are 258 and 312 K, respectively, a consequence of the different M-O bond strengths of the two oxidation states. (C) 1999 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
ISSN:	0022-3093
Date:	August 1999
Volume:	253
Number of Pages:	11
Page Range:	pp. 192-202
Publication Status:	Published
Title of Event:	18th International Congress of Glass
Location of Event:	SAN FRANCISCO, CALIFORNIA
Date(s) of Event:	JUL 05-10, 1998
URI:	http://wrap.warwick.ac.uk/id/eprint/14233

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