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Doping of a high calcium oxide metaphosphate glass with titanium dioxide

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Published
  • Ensanya A. Abou Neel
  • Wojciech Chrzanowski
  • Sabeel P. Valappil
  • L. A. O'Dell
  • David M. Pickup
  • Mark E. Smith
  • Robert J. Newport
  • Jonathan C. Knowles
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<mark>Journal publication date</mark>1/06/2009
<mark>Journal</mark>Journal of Non-Crystalline Solids
Issue number16-17
Volume355
Number of pages10
Pages (from-to)991-1000
Publication StatusPublished
<mark>Original language</mark>English

Abstract

This study investigates the effect of doping a high calcium oxide containing metaphosphate glass series (CaO)(40)(Na2O)(10)(P2O5)(50) with TiO2 (1, 3, and 5 mol. TiO2 incorporation increased the density and glass transition temperature while reduced the degradation rate (5 mol% in particular) by twofold compared with (CaO)30 system reported previously. This has been confirmed by ion release and the minimal pH changes. TiP2O7, NaCa(PO3)(3) and CaP2O6 phases were detected for all TiO2-containing ceramics. XPS showed that the surface is composed of Ca, h, and Ti. Ti was recognized mainly as TiO2, but its total amount was lower than theoretical values. P-31 magic angle spinning (MAS) NMR showed a downfield shift of the P-31 lineshape with increasing TiO2, interpreted as an effect of the titanium cation rather than an increase in the phosphate network connectivity. FTIR showed that incorporation of TiO2 increased the strength of the phosphate chains, and the O/P ratio while introducing more Q(1) units into the structure at the expense of the Q(2) units. There were no differences, however, in surface topography roughness and free energies between these glasses. These results suggested that TiO2 and CaO were acting synergistically in producing glasses with controllable bulk and structural properties.