Rational Design of Dy2O3-Doped Bi2O3–B2O3–K2O Radiation Shielding Glasses through Alkaline-Earth Modifier (MgO, ZnO, or BaO) Engineering: Structural Speciation Analysis and Mechanical Property Optimization

Abstract

This study explores the role of MgO, ZnO, and BaO additions in tuning the structural features and radiation shielding efficiency of Dy³⁺-doped B₂O₃–Bi₂O₃–K₂O glasses fabricated by melt quenching, with emphasis on photon energies corresponding to Cs-137, Co-60, and Na-22 sources. The parent composition (64.5 B₂O₃–15 Bi₂O₃–20 K₂O–0.5 Dy₂O₃, mol %) was modified by substituting 10 mol % of B₂O₃ with MgO, ZnO, or BaO. The density increased from 4.07 g cm^–3 in the Mg-containing glass to 4.21 g cm^–3 in the Ba-containing sample, indicating a clear enhancement. By using XRD, infrared spectroscopy, UV–Vis tests, and computational modeling, the relationship between structural changes and functional performance was systematically examined. The results indicate that by enhancing [BO₄] formation with its potent charge compensation, the inclusion of Mg²⁺ enhanced the network’s integrity, resulting in improved mechanical strength (elastic modulus = 103 GPa; shear modulus = 41 GPa). In contrast, although Ba²⁺ reduces mechanical strength, it provides superior radiation shielding performance, requiring only a 0.433 cm half-value layer at 0.284 MeV. While the radiation shielding properties vary across the prepared glasses, each composition demonstrates improved performance relative to conventional tellurite- and lanthanum oxide-based glasses, underscoring the role of precise compositional design in achieving multifunctionality. The results confirm that all prepared glasses have potential as radiation shielding materials, with the Mg²⁺-containing composition being particularly well-suited for uses demanding superior mechanical strength and structural robustness.