X-ray photoelectron spectroscopy of sodium borosilicate glasses

Citation
Y. Miura et al., X-ray photoelectron spectroscopy of sodium borosilicate glasses, J NON-CRYST, 290(1), 2001, pp. 1-14
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF NON-CRYSTALLINE SOLIDS
ISSN journal
0022-3093 → ACNP
Volume
290
Issue
1
Year of publication
2001
Pages
1 - 14
Database
ISI
SICI code
0022-3093(200109)290:1<1:XPSOSB>2.0.ZU;2-I
Abstract
X-ray photoelectron spectra of RNa2O . B2O3 . KSiO2 (R = 0.2 to 5.0, K = 0. 5 to 6.0) glasses were measured by a monochromatised Al-Ka XPS instrument. Chemical shifts of the core-level photoelectron spectra of the glass consti tuent ions were investigated. Peaks at the higher and lower energy sides of an Ols signal were ascribed to bridging oxide (BO) and non-bridging oxide (NBO) components, respectively. The BO component could not be separated int o the oxide ions with different environment such as Si-O-Si, B-O-Si and B-O -B. Na1s signal could not be separated into two components of Na+ ions asso ciated with [BO4/2](-) tetrahedron and NBO. For the small K values (=0.5 an d 1.0), the NBO fractions measured by XPS agreed very well with the structu ral model proposed by Dell et al. [J. Non-Cryst. Soilds 58 (1983) 1], where NBO did not appear until R = 0.5 regardless of K values. With increasing K , however, the dependence of the NBO fraction upon R gradually came to disa gree with the Dell model. At smaller R values than Rv = 0.5 +K/16, the NBO component already appeared to a considerable extent and the discrepancy bet ween the XPS results and the Dell model became more significant with increa sing K. This fact meant that additional sodium oxides were shared proportio nally between silicate and borate networks even at the small R when K was l arger than 2. A new sharing model was proposed on the basis of an acid-base concept. (C) 2001 Elsevier Science B.V. All rights reserved.