Structural, physical and ultrasonic studies on bismuth borate glasses modified with Fe2O3 as promising radiation shielding materials

Abstract

Fe-bismuth borate glass systems of composition; (70-x) B2O3+ 5 Bi2O3+15 MgO+ 5 Na2O+5 Al2O3+x where x = 0, 0.5, 1, 1.5 mol% Fe2O3 were prepared thru the known melting annealing procedure. Some of their structural, optical, physical and ultrasonic properties were measured and interpreted towards gamma irradiation up to 60 kGy. FTIR spectra display vibrations of the main triangular BO3 and tetrahedral BO4 units, BiO6 polyhedral and AlO4 units. The deconvoluted spectra diplay limited changes in the glasses structural units. UV–visible absorption spectra show peaks at∼ 220, 248 and 270 for Fe-free glass with a cutoff shift to ~ 320 and 360 nm for Fe-containing glasses. The UV peaks are correlating to absorption of the triplet Fe3+ ions and trivalent Bi3+ions. Either the optical or vibrational bands obtain an apparent moral stability against gamma irradiation doses especially before 60 kGy. Density, molar volume, optical energy band gap (Eopt), other physical parameters and ultrasonic properties e.g. longitudinal and shear ultrasonic velocities, elastic moduli, microhardness and ultrasonic attenuation coefficient (α) reveal also high stable performance against irradiation process. Presence of the polarizable Bi3+ ions helps in blocking radiation photons passage and Fe2+/Fe3+ enhances the absorption of defect color centers caused by irradiation. Additionally, the condensed AlO4 units provide the glasses structures and compactness. The stable behavior and superior optical visibility of the prepared Fe-bismuth borate glasses properties against ionizing radiation, recommend their promising usage as suitable radiation shielding candidates for protecting specialists and patients in healthcare, dentistry, veterinary and industrial environments.