Abstract
In this study, for the first time, diamagnetic 5d0 Ta5+ ions and Ta2O5 nanocrystals were utilized to enhance the structural, mechanical, magnetic, and radiation shielding of heavy metal oxide glasses. Transparent Ta2O5 nanocrystal-doped heavy metal oxide glasses were obtained, and the embedded Ta2O5 nanocrystals had sizes ranging from 20 to 30 nm. The structural analysis of the Ta2O5 nanocrystal displays the transformation from hexagonal to orthorhombic Ta2O5. Structures of doped glasses were studied through X-ray diffraction and infrared and Raman spectra, which reveal that Ta2O5 exists in highly doped glass as TaO6 octahedral units, acting as a network modifier. Ta5+ ions strengthened the network connectivity of 1–5% Ta2O5-doped glasses, but Ta5+ acted as a network modifier in a 10% doped sample and changed the frame coordination units of the glass. All Ta2O5-doped glasses exhibited improved Vicker’s hardness, magnetization (9.53 × 10−6 emu/mol), and radiation shielding behaviors (RPE% = 96–98.8%, MAC = 32.012 cm2/g, MFP = 5.02 cm, HVL = 0.0035–3.322 cm, and Zeff = 30.5) due to the increase in density and polarizability of the Ta2O5 nanocrystals.
Highlights
Transition metal oxides have been widely incorporated in vitreous materials due to optical changes and property enhancements to vitreous networks
Transparent glasses were fabricated by using reagent grade PbO, Bi2O3, H3BO3, and as-synthesized Ta2O5, which was prepared at 600 ◦C with a size of around 30 nm
Tion Bands 1 to 3 are sharp and intense in Ta2O5 prepared at 1000 °C, while these bands prepared at 600 ◦C and 800 ◦C. These results indicate that the Ta polyhedral and Ta6O126+ clusters existed in Ta2O5 prepared at 1000 ◦C due to the higher temperature
Summary
Transition metal oxides have been widely incorporated in vitreous materials due to optical changes and property enhancements to vitreous networks. Transition metal oxides strongly increase the chemical and thermal stabilities of glass formers because of their intermediary behavior related to a high coordination number of the metallic ions, resulting in higher connectivity of the glass network [1]. Ta2O5 has been found to be a modifier, in most cases, at a higher content, which exists as TaO6 units [13,14] In this case, the empty or unfilled d-orbital (outer electronic configuration 5d06s0 of Ta5+ ions strongly contribute to the large ionic refraction (23.4) and large refractive index and polarizability [15]. Ta2O5 nanocrystals were synthesized using the hydrothermal method, and their influence on glass structure, their mechanical, magnetic, and radiation shielding of Ta2O5-doped heavy metal oxide diamagnetic glasses, was investigated. The off-white final product was thermally treated at 600, 800, and 1000 ◦C by 10 ◦C/min and residual for 5 h
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