Sonochemical synthesis of iron nitride nanoparticles

A method for the preparation of nanoparticles of iron nitride powders is reported. Iron nitride particles have been synthesised by two methods. In the first, Fe(CO)5 was sonicated in a decane solution under a gaseous mixture of NH3 and H2 (3.5:1 molar ratio) at ca. 0 °C. The second method was based on nitriding the sonochemically prepared amorphous iron at ca. 400 °C for 4 h under a mixed stream of NH3–H2(3.5:1 molar ratio). Different products were obtained in the two cases. The product of the sonication of Fe(CO)5 was amorphous Fe2–3N and a small quantity of iron oxide. The X-ray diffraction patterns in the second case showed Fe4N as a main product. The magnetic properties of both products were measured. The coercive force HC of the Fe4N is 190 Oe, and the saturation magnetization sigma;s is 170 emu g–1 .