Structural study of Nd oxidation by means of in-situ synchrotron X-ray diffraction (400 <= T <= 700 degrees C)

The existence of pure cubic Nd2O3 is a debated issue in the literature, as it seems to depend on the nature of the oxide precursors and on the synthesis parameters. In this work, Nd2O3 was produced by Nd oxidation, treating first the metal powders in O-2 atmosphere (P = 1.05 atm) at low temperature (200 and 350 degrees C) and then heating the resulting partially oxidized Nd at temperatures ranging between 400 and 700 degrees C; the structural modifications were followed by in-situ synchrotron X-ray diffraction. Collected data were refined by the Rietveld method and the results revealed that a mixture of hexagonal-Nd2O3 and cubic-Nd2O3, with almost constant amounts of the two components, formed in the whole temperature. range; moreover, an incomplete oxygenation of the hexagonal phase occurred, while the cubic structure is fully oxygenated at each temperature considered. (C) 2014 Elsevier B.V. All rights reserved.