Effect of Bi2O3/CaO addition on mechanical, structural, and radiation shielding properties of Na2O–BaO-Fe2O3-B2O3-SiO2 glass ceramic

This study demonstrates the effect of CaO-enriched multi-elemental boro-silicate glasses of composition 9Na2O-5BaO-1Fe2O3-(25-x)Bi2O3-40B2O3-20SiO2-xCaO (where x = 0, 4, 8, and 12 wt.%), prepared by the meltquench method. X-ray diffraction (XRD) confirmed an amorphous structure, and X-ray fluorescence (XRF) revealed concentrations of the elemental composition, respectively. The density decreased from 3.34 to 2.98 g/ cm3, and the molar volume decreased from 51.26 to 30.94 cm3/mol at 0 and 12 wt.%CaO replacing Bi2O3. The increase in the field strength and ionic concentrations further supports an improvement in the rigidity and compactness of the glass with CaO introduction. The Fourier transform infrared spectroscopy (FTIR) demonstrated that the modification of structural units with increasing Ca2+ results in the formation of non-bridging oxygen (NBO) atoms. The mechanical properties, including Young's and longitudinal modulus, increased from 102.268 to 121.218 GPa and 110.618 to 142.817 GPa. While the Poisson ratio decreases from 0.425 to 0.414 with 0 and 12 wt.%CaO replacing Bi2O3, demonstrating the formation of a stronger bond with the borosilicate glass. The mass attenuation coefficient (MAC) was 5.759 and 4.670 cm2/g, and the half-value layer (HVL) was 0.036 and 0.050 cm at 0.05 MeV with 0 and 12 wt.%CaO replacing Bi2O3. The glass thickness at 0.5 cm revealed a radiation protection efficiency (RPE) of 100 % between photon energies of 0.015 and 0.04 MeV. The radiation shielding effectiveness of the glasses is better than that of some shielding materials, making it a good candidate for shielding radiation where the mechanical strength of glass is of priority.