δ-Sc₄Zr₃O₁₂におけるイオン照射誘起構造変化の透過電子顕微鏡法による解析

抄録

The development of radiation tolerant materials is of technological importance for the immobilization and long-term storage of surplus actinides and high-level radioactive wastes such as spent fuel from nuclear reactors. Complex oxide ceramics represent an important class of candidate materials for nuclear-waste hosts, and therefore much effort has been devoted to assess radiation damage behavior in these materials. Recent research has centered on a class of materials that possess structures related to the fluorite (CaF₂) crystal structure (called fluorite structural derivatives), because certain fluorite-structured oxides, such as UO₂ and cubicstabilized zirconia, behave quite robustly in a radiation environment. In an effort to study systematically radiation effects in fluorite structural derivatives, we recently initiated investigations into radiation damage effects in M₇O₁₂ compounds (M represents a metal cation, while O refers to an oxygen anion) . Many M₇O₁₂ compounds are known to crystallize in a so-called delta (δ) crystal structure, a structure closely related to fluorite. In this article, our recent study on ion-beam-induced structural transformations in δ-Sc₄Zr₃O₁₂ was reported.