Ternary Borosilicate Glasses Research Articles

Electron irradiation-induced elements depletion and macroscopic changes in ternary borosilicate glasses: Mechanism and composition dependence

Glass, utilized for immobilizing high-level radioactive waste, experiences a decrease in mechanical properties and an increased risk of radioactive release after being exposed to β-radiation. A series of ternary borosilicate glasses were irradiated with 10 MeV electrons to doses ranging from 1 × 104 to 1 × 107 Gy. Nano-indentation, X-ray photoelectron spectroscopy, Time-of-Flight secondary ion mass spectrometry and Fourier-Transform infrared spectroscopy were used to characterize the glasses. After irradiation, the hardness of the glass decreased dramatically; the depletion of sodium, boron, oxygen and the enrichment of hydrogen, carbon in the glass surface were observed. The diffusion coefficients and depletion depths at different doses were fitted, both related to the composition of glass. With the absorbed dose increasing, Q0 ∼ Q2 transformed to Q3 and Q4, BO3 and BO4 decreased, molecular water and hydroxyl appeared. The formation of the depletion zone caused the reduction in hardness induced by irradiation. The glass showed phase separation characteristics. The mechanism and detailed process of element depletion were discussed. The composition dependence of depletion was explained based on the energy barrier model. The diffusion coefficient of elements depends on the activation energy of alkali.

Composition‐dependent leaching behavior in ion‐irradiated borosilicate glasses: A corrosion mechanism study

AbstractEvaluating the corrosion behavior of borosilicate glass after irradiation holds vital importance for the safe geological disposal of high‐level radioactive waste. This study examined the leaching properties of three kinds of sodium‐borosilicate (RNa2O‒B2O3‒KSiO2, denoted as “NBS”) glasses with the same R but varying K under 5 MeV Xe‐ion radiation to decipher the correlation between the corrosion mechanism and glass composition. After Xe‐ion radiation, an increase in [BO3] units was observed, indicative of the glass network depolymerization. Irradiated glasses exhibited a more significant change in [BO3] units over the leaching time compared to their pristine counterparts. There is a strong correlation between the initial dissolution rates of pristine glasses, the K value, and the proportion of Na. Additionally, the initial Si dissolution rate of the NBS glasses has been accelerated by heavy ion irradiation. For the same R value over the glass series, the initial Si dissolution rates in ternary borosilicate glasses change at similar rates after irradiation. This study concluded that the variation trend in the initial dissolution rate of Si and Na differs under ion radiation.

Radiation effects of B depletion and the generation of point defects in ternary borosilicate glasses by gamma rays

Borosilicate glass is one of the base materials which can solidify high-level radioactive waste. Therefore, its resistance to radiation attracted extensive attention. The borosilicate glass samples with different compositions were irradiated with gamma rays at ambient temperature. The interaction between the gamma rays and the glass network was discussed. The radiation effects were analyzed with nano-indentation, photoluminescence, Raman, Infrared, Ultraviolet and visible absorption, and X-ray photoelectron spectroscopies. The results indicate point defects such as non-bridging oxygen hole center (NBOHC) and peroxy radical were produced in glasses after irradiation. The depletions of sodium and boron in the surface of glasses were identified, which led to a decrease in hardness. The Urbach energies increased with the absorbed dose. A new analyzing method, the noise of Raman spectrum, was deduced to analyze the glass disorder. The noise and Urbach energy depended on the concentration of NBOHC, which is led by gamma radiation.

Optical properties and zero photoelastic constant of ns2-type metal cation containing oxide glasses

Zero photoelasticity and the relevant optical properties in binary RO–SiO2 (R = Sn, Pb) and R′2O3–SiO2 (R′ = Sb, Bi) and ternary Bi2O3–B2O3–SiO2 glasses were systematically studied. The zero photoelastic silicate glass leads to zero stress-induced birefringence, providing application to an optical lens, a filter, a beam splitter, and a fiber optic sensor without stress-induced birefringence. In this study, a variety of zero photoelastic binary silicate and ternary borosilicate glasses with optical bandgaps of 3.1–3.9 eV containing highly polarized ns2-type cations are reported.

Composition-dependent mechanical property changes in Au-ion-irradiated borosilicate glasses

The mechanical property changes in three kinds of ternary borosilicate glasses (named NBS glasses) induced by 8.0-MeV Au3+ were studied by nanoindentation measurements. For these borosilicate glasses, the molar ratio R = [Na2O]/[B2O3] is varied (1.34, 0.75, and 0.40 for NBS1, NBS2, and NBS3, respectively), while their molar ratio K = [SiO2]/[B2O3] is fixed at 4.04. The nanoindentation results indicate that both the hardness and reduced Young modulus were decreased after irradiation. No obvious difference in both hardness and modulus variations of these three NBS glasses was observed. Based on the main structures of their pristine samples, the reedmergnerite groups containing Si-O-BIV may be the structural origin of Au-ion-irradiated mechanical property changes in the homogeneous glasses with R > 0.5. However, the modification of the silica network and phase separation may dominate the mechanical property changes for glasses with R ≤ 0.5. The ion- and electron-irradiation-induced mechanical property changes of these NBS glasses were also compared in this study. The extended incubation dose and the slower decreasing rate can be observed in electron-irradiation-induced hardness and modulus variations, which may be caused by the different mechanisms between both irradiation scenarios.