Structure and physical properties of Li2O–Fe2O3–P2O5 glasses

Abstract

The structure and physical properties of (50−x)Li2O·xFe2O3·50P2O5 glasses (0 ≤ x ≤ 25 mol%) have been studied by different techniques. The amorphous nature of the glasses has been affirmed by x-ray diffraction. By increasing Fe2O3 content, the Fe/P ratio increases, and the covalent P–O–Fe bonds also increase, which leads to a more durable structure. For Fe2O3 ≤ 15 mol%, Fe ions enter the network as a network modifier breaking P–O–P and P = O bonds and act as a network former for Fe2O3 > 15 mol%. Hardness (H v) increases with increasing Fe2O3 content because of the strengthening of the network. Studying the chemical durability of the investigated glasses has shown that the compositions containing high content of iron oxide are more water−resistant. Moreover, density and molar volume increase with different rates with Fe2O3 content. It is believed that the conduction in these glasses is predominantly ionic and dominated by Li+ ions as the main charge carriers. The contribution of the polarons to the conduction process has a negligible impact compared to that of the ionic conduction by Li+ ions. Regarding the shielding properties, the mass attenuation coefficient was calculated by the XCOM program and other photon shielding properties like mean free path (λ), and half value layer (HVL) were calculated within the energy range of 0.335 MeV-9 MeV. The effect of replacing lithium oxide by iron oxide has been analyzed which proved that iron is more efficient than lithium in attenuating and removing fast neutrons.