CRYSTALLOGRAPHIC AND MAGNETIC-PROPERTIES OF FINE IRON NITRIDE POWDERSPREPARED BY SOLID-STATE REACTIONS BETWEEN IRON AND ORGANIC H-X(CN)-RING COMPOUNDS

In this work morphological, crystallographic and magnetic properties o f iron nitride powders prepared by room temperature mechano-chemical p rocessing, were studied by SEM, XRD and VSM methods. Nitridation react ion occurs during bah milling of a stoichiometric mixture of alpha Fe powder and highly reactive complex amine compounds: piperazine, pyrazi ne and pyrazole in the molar ratio 3:1 (Fe:N). The amount of nitride p hase produced, depends on milling time, annealing temperature and on t he chemical reactivity of the amine compound with iron. Calculation of crystal lattice parameters show that prepared nitrides are similar to stoichiometric Fe3N hcp type structure. Lattice expansion was found f or hexagonal planes due to increase in nitrogen concentration. Magneti c hysteresis parameters were found to be very sensitive to changes in chemical composition. As the amount of nitrogen increases magnetic rem anence and coercivity increase but magnetization and calculated averag e magnetic moment per Fe atom decrease.