STRUCTURE AND MAGNETIC-PROPERTIES OF MECHANICALLY ALLOYED IRON NITRIDE POWDERS

Systematic investigations were carried out on the synthesis of Fe nitr ide powders using a combined mechanical alloying and vacuum annealing technique. The results showed that supersaturated Fe and amorphous pha ses are formed by mechanically alloyed powder mixtures made of Fe2.33N and Fe powders with the starting compositions Fe100-xNx (x=11, 14, 20 ). The saturation magnetization of Fe100-xNx powders can be improved b y vacuum annealing, and reaches a maximum value of 245 e.m.u. g(-1) at room temperature for the starting composition Fe86N14. The appearance of the alpha ''-Fe16N2 phase is responsible for the anomalously high saturation magnetization in mechanically alloyed Fe86N14 powder after annealing at 240 degrees C for 4 h.