Intergrowth Structure in U- and Hf-Bearing Pyrochlore and Zirconolite: Analytical Electron Microscopy Investigation

2003 ◽  
Author(s):  
Huifang Xu
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Analytical Electron

scholarly journals Analytical Electron microscopy Investigation of Au/TiO2 Thin Films Deposited on the Glass Substrate

2013 ◽  
Vol 19 (S2) ◽  
pp. 1498-1499
Author(s):  
M. Kawasaki ◽  
M.-J. Chen ◽  
J.-R. Yang ◽  
W.-A. Chiou ◽  
M. Shiojiri
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Glass Substrate ◽  
Analytical Electron Microscopy ◽  
Tio2 Thin Films ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Analytical Electron

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

High-Resolution Analytical Electron Microscopy Investigation of Metastable Tetragonal Phase Stabilization in Undoped, Sol-Gel Derived Zirconia Nanoceramics

2003 ◽  
Vol 788 ◽  
Author(s):  
Vladimir P. Oleshko ◽  
James M. Howe ◽  
Satyajit Shukla ◽  
Sudipta Seal
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Sol Gel ◽  
Analytical Electron Microscopy ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Analytical Electron ◽  
20 Nm ◽  
Electron Energy Loss ◽  
Hydrolysis Of

ABSTRACTThe mechanisms underlying stabilization of the metastable tetragonal (t)-phase in sol-gel derived, nanocrystalline ZrO2 were studied by high-resolution analytical electron microscopy, utilizing parallel electron-energy loss (PEEL) and energy-dispersive X-ray spectroscopies. The powders were synthesized by hydrolysis of Zr (IV) n-propoxide at ratios of molar concentration of water to Zr n-propoxide, R=5 and 60, respectively, followed by calcination at 400°C. Dense particles of the as-precipitated ZrO2 (R=5) revealed 4–11 nm-sized nanocrystals embedded in the amorphous matrix that may serve as nuclei for the t-phase during calcination. The calcined particles consist of 10–100 nm–sized t-crystals. For as-precipitated ZrO2 (R=60), week aggregates (50–100 nm) of largely amorphous 4–20 nm-sized particles after calcination yield a mixture of t-and monoclinic (m-) nanocrystals. PEELS fingerprints of the band structure with the intensity threshold matching the expected position of a direct bandgap at 4–5 eV allow to differentiate between the amorphous and nanocrystalline ZrO2. Stabilization of t-phase (R=5) with sizes up to 16 times larger than reported earlier is likely due to strain-induced confinement from surrounding growing grains, which suppress the volume expansion associated with the martensitic t-m transformation. For R=60, loose nanoparticle agglomerates cannot suppress the transformation. In this case, the t-phase may be partially stabilized due to a crystal size effect and /or to the presence of m-phase.

Sign in / Sign up

Export Citation Format

Share Document