abstract
The structure of glasses with composition x TiO2 center dot(65 - x) P2O5 center dot 35 CaO (x = 0-30 mol%) has been studied and their glass transition temperature, Raman and NMR spectra have been analysed. For TiO2-free glass two phosphate species have been identified as Q(2) and Q(3). Increasing TiO2 content in glass compositions results in the disappearance of the Q3 and Q2 species and in the formation of, mainly, pyrophosphate structure, Q(1). In calcium titanophosphate glass with higher TiO2 content the structure consists of a distorted Ti octahedral linked to pyrophosphate unit through P-O-Ti bonds. In these glass series the structural cohesion increases with TiO2, although a depolymerization in the original P-O-P network occurs. The study of these glasses and the understanding of their structural characteristics can give a valuable contribution for the clarification of their degradation behaviour namely in biological environments. (C) 2009 Elsevier Ltd. All fights reserved.
keywords
SODIUM TITANOPHOSPHATE GLASSES; PHOSPHATE-GLASSES; RAMAN-SPECTROSCOPY; ULTRAPHOSPHATE GLASSES; MECHANICAL-PROPERTIES; CERAMICS; CRYSTALLIZATION; SYSTEM; TIO2; BETA-CA2P2O7
subject category
Materials Science
authors
Silva, AMB; Correia, RN; Oliveira, JMM; Fernandes, MHV
our authors
Ana Margarida Batista da Silva
PhD Student
J. Martinho Oliveira
Coordinator Professor
Maria Helena Figueira Vaz Fernandes
Retired ProfessorGroups
G4 - Renewable Materials and Circular Economy
G5 - Biomimetic, Biological and Living Materials
acknowledgements
The authors acknowledge the Portuguese Foundation of Science and Technology for the financial support through the project POCI/CTM/60761/2004.