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Phase evolution from Ln 2 Ti 2 O 7 (Ln=Y and Gd) pyrochlores to brannerites in glass with uranium incorporation
Author(s) -
Zhang Yingjie,
Kong Linggen,
Aughterson Robert D.,
Karatchevtseva Inna,
Zheng Rongkun
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15051
Subject(s) - pyrochlore , raman spectroscopy , materials science , scanning electron microscope , phase (matter) , spectroscopy , transmission electron microscopy , selected area diffraction , uranium , crystallography , analytical chemistry (journal) , diffuse reflectance infrared fourier transform , coordination number , mineralogy , ion , chemistry , metallurgy , nanotechnology , optics , biochemistry , physics , organic chemistry , chromatography , quantum mechanics , photocatalysis , composite material , catalysis
Ln 2 Ti 2 O 7 (Ln=Y and Gd) pyrochlore glass‐ceramics have been fabricated successfully via internal crystallization. Subsequently, the phase evolution from Ln 2 Ti 2 O 7 pyrochlores to Ln 0.5 U 0.5 Ti 2 O 6 brannerites in glass with uranium (U) substitutions on the Ln‐site of Ln 2 Ti 2 O 7 has been investigated using X‐ray diffraction, scanning electron microscope‐electron dispersive spectroscopy, transmission electron microscopy, Raman and diffuse reflectance spectroscopy. Combined characterization by XRD , SEM ‐ EDS and TEM SAED confirms the structures and phase evolution while Raman spectroscopy reveals characteristic vibration modes for both pyrochlore and brannerite. In addition, DRS of the U 5+ ion has been used to probe the phase evolution, with the corresponding f ‐ f transition band of 2 F 7/2 energy level significantly shifting to longer wavenumbers due to the local coordination environment changing from eightfold coordination in pyrochlore to sixfold coordination in brannerite.