Structure of Titanophosphate Glasses Studied by X-ray and Neutron Diffraction

Abstract

The structure of binary (TiO2)x(P2O5)1−x glasses with x = 0.60, 0.65 and a ternary K2O-TiO2-P2O5 (KTP) glass were studied by X-ray and neutron diffraction. The experiments were performed at the high-energy beamline BW5 of the synchrotron DORIS (Hamburg/Germany) and at the GEM instrument of the neutron source ISIS (Chilton/UK). Gaussian fitting of well-resolved first-neighbor peaks in the correlation functions of the binary glasses with TiO2 contents of 0.65 and 0.60 result in Ti-O coordination numbers of 5.65 ± 0.2 and 5.9 ± 0.2, respectively. Distorted TiO6 octahedra and isolated PO4 units form the glassy networks, with a small number of lower coordinated Ti sites for the 0.65 TiO2 glass. For comparison, only TiO6 octahedra are found for a ternary K2O-TiO2-P2O5 glass. The Ti-O coordination numbers are compared with a structural model where all oxygen atoms occupy sites in Ti-O-Ti, Ti-O-P or P-O-P bridges. The presence of three-coordinated oxygens must be assumed for the binary glasses, whereas a structure with nearly all oxygen atoms forming network bridges exists for the ternary KTP glass.

Department(s)

Materials Science and Engineering

Sponsor(s)

German Research Association
National Science Foundation (U.S.)

Keywords and Phrases

X-Ray Diffraction; Neutron Diffraction/Scattering; Short Range Order; Phosphates; Titanates

International Standard Serial Number (ISSN)

0022-3093; 1873-4812

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2007 Elsevier, All rights reserved.

Publication Date

15 Jun 2007

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