The Preparation Of Iron Nitride Powder And Research Of Its Microwave Properties

In recent years, microwave absorbing materials attracted widespread attention in and outside. At present, people are not only trying to improve the properties of traditional absorbing materials but also are exploring the new type to reach the thinner, lighter, wider and stronger microwave absorbing target. Iron nitride is mainly used for magnetic recording materials while it was reported only a few at the microwave absorbing area, the rich iron phases of iron nitride show high saturation magnetization and well chemistry stability which may has good properties of microwave absorbing.The processing of formation conditions about different phases of iron nitride got probed, and pure micron Fe2N, Fe3N, Fe4N and nanoscale Fe3N powder were successfully synthesized, the result shows that high ratio ammonia and low hydrogen gas are more likely to promote the formation of iron rich phase. The electromagnetic parameters of the iron nitride at the frequency of 2～18GHz were measured by Agilent N5242A vector network analyzer (VNA), and the static magnetic properties and microwave properties of the iron nitride were studied and analyzed. At the same mass fraction condition, the imaginary of permeability of Fe4N powder was higher than that of carbonyl iron powder and the dielectric of the former was a little higher than that of the carbonyl iron powder. Fe4N powder and carbonyl iron powder were treated at 350℃ on the magnetic field, By testing their electromagnetic parameters, it show that the Fe4N is superior to carbonyl iron powder in the heat resistance.After surface modification on the magnetic absorbing materials, the complex permeability, dielectric constant and resonance frequency has remarkably improved, the using of well dispersant can make the powder well dispersed and the dielectric reduced. The cobalt iron alloy powder was modified through the high energy ball milling equipment, under the conditions of different ball milling time, rotational speed, type of dispersants, and other parameters, the reason about the effect of the different conditions were studied. Uniformly mixed with the paraffin under the 89 percent quality fraction of cobalt powder, the electromagnetic parameters testing shows that the complex permeability is 3.7-3j, complex dielectric constant 27-0.9j, at the frequency of 2GHz under lmm thick coating the reflection loss reaches -2.7dB. The microwave absorption of modified iron cobalt alloy powder is greatly improved compared with the raw material...