Preparation of Iron Nitride Fe16N2 Nanoparticles by Reduction of Iron Nitrate

This paper describes the preparation of Fe16N2 nanoparticles by reduction of iron nitrate. First, alpha-Fe nanoparicles were prepared by reduction of iron nitrate powder under hydrogen flow at 623 K for 5 h. The alpha-Fe nanoparticles with the site of about 140 nm in SEM image, were then nitrided under an ammonia flow at 423 K for 72 h. The sample consisted of Fe16N2 and alpha-Fe phases from XRD analyses and showed the magnetization of 207 A m(2) kg(-1) under magnetic field of 1.43 MA m(-1) at room temperature. The average particle size was revealed as 140 nm by TEM observations. To investigate the possibility of the obtained nanoparticles as microwave absorption materials, the electromagnetic wave absorption properties were investigated in a composite of the obtained nanoparticles and resin. The sample showed a good microwave absorption properties (Reflection loss: R.L. < -20 dB) in 15 similar to 19 GHz range. Therefore, it is concluded that Fe16N2 nanoparticles have a possibility to become a candidate for microwave absorbers in 10 similar to GHz range.