Ion-irradiation response in the mechanical properties and structure of a boron-doping iron phosphate glass

Abstract

We investigated the irradiation effects of a ternary 36Fe2O3−10B2O3–54P2O5 glass (in molar percent; denoted as “10B”) which has been deemed as an advanced candidate for high-level nuclear waste in recent years. The mechanical property changes upon 5.0 MeV Xe20+-ion irradiation were studied by nanoindentation, and the structural response was studied by grazing-incidence X-ray diffractometer (GIXRD) and Fourier-transform infrared microspectroscopy (μFTIR). Both hardness and Young's modulus decreased after irradiation, and the saturated variations (–24 % for hardness and –5 % for modulus) are lower than those of international simplified glass (ISG). The 10B glass also manifests an extended lifespan over ISG in terms of mechanical durability. The GIXRD confirms that the sample remains amorphous even irradiated after the maximum dose, while the μFTIR-derived structure changes suggest a depolymerized P-network, a P–B demixture, and a decreased boron coordination number, which should be the main cause of the mentioned mechanical property changes.