Chemical diversity of iron species and structure evolution during the oxidation of C14 Laves phase Zr(Fe, Nb)2 in subcritical environment. (January 2020) - Cao, Guoqin
Graphical abstract: Highlights: During oxidation, multi-layered structure is formed on the surface of C14-Zr(Fe, Nb)2 . Oxidation induced amorphization is found with semi-free iron internally dispersed. The migration of semi-free iron to the surface results in the Fe-poor amorphous layer. The Fe-poor amorphous oxide layer shows a stable barrier effect. Abstract: C14 Laves phase Zr(Fe, Nb)2 was fabricated and oxidized in a subcritical environment. Electron energy loss spectroscopy was used to study the migration and chemical state evolution of the elements. The oxidation process was accompanied by the formation of multilayered oxide scale, consisting of a crystalline oxide layer, amorphous oxide layer (Fe-poor) and Zr-Nb-Fe-O amorphous layer. The formation of closely bonded, semi-free and metallic iron species as well as the out diffusion of Fe contribute to the multilayered structure growth. The amorphization of the C14 phase occurred with the incorporation of oxygen, which preferentially bonded with Zr and Nb.