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This study examined the influence of iron oxide incorporation on the durability of phosphate glasses with the following formula 50P2O5 -33·33K2O-(11·11-x/2)CaO-(5·56-x/2)MgO-xFe2O3 with 0=x=2 mol%. Indeed, the effects of adding iron on the glass structure, physicochemical properties, thermal properties, and especially, dissolution behaviours were investigated. The glasses were prepared using the classical melt quenching technique at 1000°C. The characterisation was performed using differential thermal analysis, x-ray diffraction, density measurements, Raman spectroscopy and Fourier transform infrared spectroscopy. Dissolution behaviours were followed by measuring weight loss and pH. The substitution of calcium and magnesium for iron increased the characteristic temperatures (Tg, Tc, Tf) and reduced the molar volume, showing a more compact phosphate glasses network. Structural characterisation showed that the glass network is composed mainly of metaphosphate chains. The dissolution behaviours of the processed glasses revealed that the introduction of Fe2O3 to the phosphate glasses can improve the chemical durability due to the ionic crosslinking between the nonbridging oxygen atoms of the phosphate chains, which explains the changes in their physicochemical properties. [ABSTRACT FROM AUTHOR]

In this work, manganese was suggested to improve the durability of 50P2O5-33·33K2O-(11·11-x/2) CaO-(5·56-x/2) MgO -xMnO glasses with 0≤x≤ 2 mol%. Indeed, its effect on the glass structure, thermal properties, physicochemical properties, and in particular, dissolution behaviours have been studied. The conventional melt-quenching technique was used to produce glasses at 1000°C and they were characterised by differential thermal analysis, density and molar volume measurements, x-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy. Dissolution behaviours were tracked by measuring weight loss and pH. Molar volume measurements showed that phosphate glasses become more compact by incorporating MnO. Structural characterisation using Raman and infrared spectra proved that the glass network is composed mainly of metaphosphate chains. The dissolution results showed that incorporating manganese was an effective method to change the phosphate glasses' chemical durability due to their ionic crosslinking between the nonbridging oxygen atoms of the phosphate chains, corresponding to the change in thermal properties (Tg, Tc and Tf). [ABSTRACT FROM AUTHOR]