posted on 2021-08-09, 16:07authored byLe Fu, Jeromy Williams, Chiara Micheletti, Bryan E. J. Lee, Guofu Xu, Jiwu Huang, Håkan Engqvist, Wei Xia, Kathryn Grandfield
The
distribution of dopant atoms plays a key role in the effectiveness
of doping, thereby requiring delicate characterizations. In this study,
we found that energy-dispersive X-ray spectroscopy (EDX) and electron
energy loss spectroscopy (EELS) techniques in scanning transmission
electron microscopy (STEM) were not adequate to reveal the distribution
of yttrium and the chemical composition of the ZrO2/SiO2 heterophase interface in an yttrium-doped ZrO2–SiO2 nanocrystalline glass-ceramic. Atom probe
tomography (APT) is rarely utilized to characterize ceramics due to
some inherent difficulties. However, we successfully revealed the
three-dimensional distribution of ZrO2 nanocrystallites
and SiO2 matrix at the atomic scale with APT under optimized
and well-controlled conditions. We also found that the ZrO2 nanocrystallites had a special core–shell structure, with
a thin Zr/Si interfacial layer as a shell and a ZrO2 solid
solution as a core. Yttrium dopants showed interfacial segregation
at both ZrO2 grain boundaries and the ZrO2/SiO2 heterophase interfaces.