Glycine-nitrate combustion engineering of neodymium cobaltite nanocrystals

NdCoO3 nanocrystals formed via glycine-nitrate combustion method followed by heat treatment has been systematically studied. Formation of NdCoO3 nanocrystals with minimal size of 7-10 nm from X-ray amorphous combustion products has been elucidated to be a very rapid process, occurring at the temperature of 550-600 degrees C for 5-30 min. The comparison of the minimum sizes of NdCoO3 crystallites obtained from the offered empirical relation d(min) = l(unit cell).N(where N is 7-12 and l(unit cell) is elementary cell parameter) and the data determined on the basis of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed good correlation. The existence of special nanoporous microstructure and spatial limitations prevent NdCoO3 particle growth. The kinetic equation based on Avrami-Erofeev nucleation model was offered to be correlated well with experimental data of fractional conversion (alpha) versus isothermal time (tau). The apparent activation energy (E-a = (338 +/- 32) kJ) of formation of NdCoO3 nanocrystals from X-ray amorphous combustion products obtained in excess of oxidant followed by heat treatment at 550-600 degrees C was determined.