Preparation of the single phase γ′-(Fe1−xNix)4N compounds (0 ≤x ≤ 0.6)
Single phase γ′-Fe4N type (Fe1−xNix)4N compounds (0 ≤ x ≤ 0.6 have been synthesized for the first time by controlled heat treatment of iron-nickel oxalates in a gaseous flow of NH3 xand H2. The preparation processes were investigated using differential scanning calorimetry (DSC), X-ray diffraction and Mössbauer spectroscopy. The results confirmed that annealing of oxalates in the NH3 and H2 atmosphere included the processes of dehydration, decomposition and reduction, nitrogenation and thermal decomposition of the nitrides. The decomposition and reduction occur simultaneously. The final products depend on the flow rate ratio of NH3 ∶ H2 and the annealing temperature. The formation conditions for the single phase γ′-Fe4N type (Fe1−xNix)4N compounds are related to the nickel concentration, with increasing nickel content, the nitrogenation temperature decreased, in contrast the flow rate ratio of NH3∶ H2 increased.
KeywordsNickel Heat Treatment Differential Scanning Calorimetry Dehydration Nitrides
Unable to display preview. Download preview PDF.
- 9.S. F. Matar, J. G. M. Armitage, P. C. Riedi, G. Demazeau andP. Hagenmüller,Eur. J. Solid State Inorg. Chem. 26 (1989) 517.Google Scholar