Change in the structure of niobium pentoxide due to mechanical and thermal treatments
Abstract
The structure and properties of amorphous niobium pentoxide obtained from its H-phase by prolonged grinding were studied by X-ray diffractometry, IR and Raman spectroscopy, and thermal analysis. The short range order at distances less than 0.5 nm was always preserved as detected from the radial distribution function, even after prolonged grinding. The amorphized Nb2O5 showed no peak corresponding to the stretching of collinear NbONb bonding around 850 cm−1 in both Raman and IR spectra. The mechanically amorphized niobium pentoxide has a structure similar to the TT-phase and not to the starting H-phase. The amorphous state obtained by grinding is an intermediate in the course of the transformation from H- to TT-phase, either with the insufficient shift of Nb or the incomplete construction of the bipyramidal hexagonal polyhedra necessary to form a stable TT-phase. The structural details for these processes are also discussed.
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Ultrafast-laser powder bed fusion of oxygen-deficient Nb<inf>2</inf>O<inf>5</inf> ceramics with highly improved electrical properties
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Lanthanide-doped niobium oxide nanoparticles on nanoarchitectured silica spheres as potential probe for NIR luminescent markers
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