Effects of MoO3 and Nd2O3 on the structural features, thermal stability and properties of iron-boron-phosphate based glasses and composites

• Published in: Journal of nuclear materials 2022-03, Vol.560, p.153500, Article 153500
• Main Authors: Wang, Fu, Wang, Yuanlin, Zhang, Daiyu, Hao, Yan, Liao, Qilong, Zhu, Hanzhen, Zhou, Junjie, Zhu, Yongchang
• Format: Article
• Language: English
• Subjects: Boron; Composite materials; Crystallization; Durability; Iron; Lanthanide phosphates; Molybdenum; Molybdenum trioxide; Monazite; Neodymium; Phase composition; Phosphate based materials; Radioactive wastes; Structural features; Structural stability; Thermal properties; Thermal stability
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2021.153500

•The solubility limit of Nd2O3 in Mo-doped Fe-B-phosphate glasses is about 2 mol%.•NdPO4 phase forms in the Fe-B-phosphate glasses containing Nd2O3 higher than 3 mol%.•Nd2O3 and MoO3 enhance the crystallization of NdPO4 phase in Fe-B-phosphate glasses.•Q0 units decrease, [MoO4], Q1 and Q2 units increase with increasing Nd2O3 and MoO3.•Thermal stability is enhanced by MoO3, but decreased by the formation of NdPO4 phase. Three series of iron-boron-phosphate based glasses and composites as hosts for MoO3 and Nd2O3 were prepared by a melt-quenching process. The effects of MoO3 and Nd2O3 on phase composition, structural features, thermal stability and aqueous durability of the iron-boron-phosphate glasses and composites were investigated in detail. The results show that the 5∼15 mol% MoO3 containing samples with Nd2O3 content less than 3 mol% are fully amorphous, monazite NdPO4 phase is detected in their amorphous structure while more than 3 mol% of Nd2O3 incorporated. Generally, the incorporation of Nd2O3 and MoO3 enhances the crystallization of NdPO4 phase, and induces the decrease of Q0 units and the increase of [MoO4], Q1 and Q2 units. Thermal stability of glassy phase in the samples is enhanced with the increase in MoO3 content, although its thermal stability decreases due to the formation of NdPO4 phase. Moreover, the reasons on the variations of structure and thermal stability are discussed. LRMo are about 10−4 ∼ 10−3 g·m−2·d−1 for 14 days and LRNd are believed to be less than ∼10−6 g·m−2·d−1, indicating their good aqueous durability. The conclusions provide researchers with the roles of MoO3 and Nd2O3 in iron-boron-phosphate based glasses and composites as potential hosts for Mo- and Nd-containing nuclear waste.