Cation distribution in nanocrystalline (Co, Ni)Al2O4 Spinel

In the present study, the cations Co2+/Ni2+ and Al3+ distribution in nanocrystalline (Co, Ni)Al2O4 spinel have been investigated using X-ray and transmission electron microscopy. The nanocrystalline (Co, Ni) Al2O4 spinet has been synthesized using mechanically activated Al70Co15Ni15 quasicrystalline precursor through annealing at 600 degrees C in controlled oxygen atmosphere. The mechanical activation of single phasic decagonal Al70Co15Ni15 quasicrystal was carried out in a high energy attritor ball mill for 40 h with 40:1 ball to powder ratio using toluene as a process control agent. The high resolution x-ray diffraction data has been refined by the Rietveld method using JANA2006 and subsequently, the corresponding structure has been constructed using Diamond4.0. The structure was also confirmed by analysis of transmission electron microscopy linearized diffraction pattern profile of D-values and corresponding plane. These analyses indicate that the cations Co2+ and Ni2+ distributed in the tetrahedral coordinated sites are the dominant species in the normal spinel phase. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.