Structural and Physical Properties Study of Some Phosphate Glasses Used for Radiation Shielding

Abstract

Mossbauer Effect (ME) and Infrared (IR) spectroscopes are used to study the structure of some iron-sodium phosphate glasses containing strontium, with composition [(70-x) mol% P₂O₅. x mol% SrO, 15 mol% Fe₂O₃.15 mol% Na₂O, where x= 3, 6,9,12 and 15]. These glasses can have many interesting applications especially as gamma ray attenuators. The amorphous nature and the glassy state character of these glasses can be confirmed from comparing the experimental and empirical values of both their density and molar volume. It was found that, as SrO was gradually increased the density increased while the molar volume decreased which may be due to the gradual decrease of the number of oxygen ion density in the glass networks. The micro-hardness and magnetic susceptibility are also increased, which can be attributed to the gradual migration of iron from glass network modifier (GNM) to glass network former (GNF) positions, as confirmed by IR and ME results. IR and ME analysis indicated that both ferric and ferrous have tetrahedral and octahedral symmetry respectively and acting as GNF and GNM at different SrO contents. The gradual replacement of P₂ O₅ by SrO force the iron to transfer from GNM to GNF. The gamma-ray mass attenuation coefficient increased with the gradual increase of Sr²⁺ as heavy metal, while the HVL decreased. On the other hand the attenuation coefficient decreased with the increase of gamma-ray photon energy. So, these glasses can be used as transparent shielding materials for low gamma-ray energies and to capsulate the radio-active wastes, while the sample containing 15 mol% SrO, exhibits the highest attenuation coefficient.