Structure, mechanical, and chemical performance evolution of aluminosilicate glass modified by Nd2O3

In this paper, the simulated nuclear waste was successfully immobilized by using aluminosilicate glass made from natural granite material without other additive agents. The neodymium-doped matrix’s phase composition, microstructure, element distribution, hardness, density, indentation fracture toughness, and aqueous durability were analyzed. The results show that the samples with a neodymium content of 10 wt.% are fully vitrified and reach the maximum neodymium solubility. The silicate tetrahedra of glass networks mainly exist in sheets (Q³) and frame (Q⁴) units. Neodymium oxide acts as a glass modifier and destroys the sheet form and may precipitate metal elements in the matrix, resulting in a Vickers hardness of up to 8.17 GPa for this aluminosilicate glass. However, the indentation fracture toughness decreases. Moreover, NR_Nd is about 10⁻⁷ ~ 10⁻⁸ g·m⁻²·d⁻¹ during the 28-day aqueous durability test, indicating its excellent aqueous durability. This work provides a new idea for immobilizing radionuclides via glass.