Direct nitriding of micron-sized carbonyl iron powders with spherical particles was carried out under conditions of thermal coupling of self-propagating high-temperature synthesis processes. Urea was used for iron nitriding. The nitriding products are composite materials based on the α-Fe, ε-FeN, FeC and FeN phases. X-ray phase analysis and chemical analysis methods showed that when the urea content is more than 15 wt. %, iron carbonitride ε-FeNC is formed in a mixture with iron, in which the nitrogen atoms in the ε-FeN crystal lattice are partially replaced by carbon. The iron nitriding products are soft magnetic ferromagnetic materials and have high values of specific magnetization from 142 to 157 emu/g.
Barinova et al. (Wed,) studied this question.