Novel complex ceramic oxides, Ln2TiO5 (Ln = La, Sm, Gd, Tb, Dy, Ho, Er, and Yb), for polyphase nuclear waste‐forms

• Published in: Journal of the American Ceramic Society Vol. 103; no. 10; pp. 5536 - 5545
• Main Authors: Aughterson, Robert D., Lumpkin, Gregory R., Smith, Katherine L., Cairney, Julie M.
• Format: Journal Article
• Language: English
• Published: Columbus Wiley Subscription Services, Inc 01.10.2020
• Subjects: Crystal structure; Crystallinity; Erbium; Fluence; Gadolinium; Irradiation; Krypton; Lanthanides; nuclear waste; pyrochlore; Radiation tolerance; Radioactive wastes; Symmetry; Titanates; Ytterbium
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.17318

As part of a broader study of ceramic nuclear waste‐forms, four different lanthanide titanates were fabricated; La0.1Sm0.1Gd0.1Tb0.1Dy0.3Ho0.1Er0.2YbTiO5, Sm0.3Gd0.3Dy0.3Yb1.1TiO5, Sm0.1Gd0.4Dy0.4Yb1.1TiO5, and Sm0.2Gd0.2Dy0.2Yb1.4TiO5. The aim was to produce single‐phase novel materials with cubic symmetry, capable of incorporating a wide variety of cations and with acceptable radiation tolerance. The chemistry flexibility and radiation tolerance are some of the major desirable properties for nuclear waste‐form materials. By using multiple lanthanides the average lanthanide radius can be controlled and consequently the structure, along with properties such as radiation tolerance. The radiation tolerance was assessed using in situ 1 MeV krypton irradiation and transmission electron microscopy characterization. Those materials for which cubic symmetry was achieved displayed better radiation tolerance; a greater critical fluence of ions (Fc) was required for the crystalline to amorphous transition, and a lower temperature was required to maintain crystallinity (Tc) during irradiation.