The practical possibility of synthesizing micron-size corrosion-resistant powder materials based on lower and higher nitrides of the Fe-N system in the form of both a bulk composition and a “core-shell” system was implemented at relatively low temperatures. Information on the elemental and chemical composition of iron nitrides was obtained using the methods of Auger electron spectroscopy and X-ray quantitative analysis. Fe3N and Fe4N phases were identified in the volume of microcrystals in the form of compositions with unreacted α-Fe without foreign impurities in the temperature range of 300–350°C. The highest mass concentration of the Fe4N phase was observed at 350°C and a nitriding time of 60 min (α-Fe, 14.70%; Fe3N, 24.50%; and Fe4N, 60.80%). Porous nanocoatings were synthesized on the surfaces of carbonyl iron microparticles at 165°C and a synthesis time of 420 min. This nanocoating has a thickness of ∼10–15 nm and, in the first approximation, corresponds to the ∼Fe15.7N2 compound.