Structure–property relationships of Fe2O3 doped novel oxyfluorophosphate glasses

• Published in: Journal of non-crystalline solids 2014-11, Vol.404, p.151-161
• Main Authors: Johnson, B., Sudhakar, B.K., Rama Krishna Chand, N., Rayapa Reddy, K., Srinivasa Rao, G.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Crystalline state (including molecular motions in solids); Crystallographic aspects of phase transformations; pressure effects; Density; Dissolution; Durability; Exact sciences and technology; Expenses; Glass; Glasses (including metallic glasses); Infrared and Raman spectra; Lattice dynamics; Liquids; Materials science; Molar volume; Networks; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Phosphate glasses; Physics; Specific materials; Structure of solids and liquids; crystallography; Thermal stability
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2014.08.024

The relationship between the network structure and properties of iron containing novel oxyfluorophosphate glasses with the composition 20ZnO–20CaF2–(60−x)P2O5:xFe2O3 with 0≤x≤5mol% has been studied. The density, molar volume, oxygen molar volume and oxygen packing density studies helped to understand the structural changes occurring in these glasses. The dissolution rate and pH of the immersion liquid are measured to explain the chemical durability of the glasses. Differential thermal analysis studies are carried out to analyze the thermal stability of the studied glasses. Deconvoluted infrared and Raman spectra of the glasses are analyzed to determine the relative areas of the vibrational bands corresponding to different structural units. Analysis of the vibrational spectra in conjunction with the other properties reveals that Fe2O3 enters the glass matrix in the form of Fe2+ and Fe3+ ions through the formation of more stable POFe2+ and POFe3+ bonds at the expense of easily hydrated POP bonds. [Display omitted] •DTA indicates the increasing trend of thermal stability against devitrification.•FTIR studies indicate the presence of iron ions in both Fe2+ and Fe3+ states.•Studies show the presence of iron ions both in Oh and Td positions.•Conversion of Qn units is in accordance with the disproportionation reaction.•Fe2O3 doping caused the replacement of POP bonds by stable POFe bonds.