Preparation And Properties Of Carbonyl Iron Radar Wave Absorber

With the development of advanced technology in radar detection, more and more attention has been paid upon Stealth Technology (a technology of reducing the possibility of being detected by radar) . Reducing the radar cross section (RCS) of military targets is one of the most important measures in Stealth Technology. There have been two basic approaches to accomplish RCS reduction: shaping to minimize backscatter, and coating for energy absorption and cancellation. The latter is usually named as Radar Absorbing Materials (RAM). When RAM is applied to an object, its radar cross section (RCS) can be reduced through the conversion of radar energy into heat by the RAM. Due to the restriction of aerodynamics and requirement of maneuverability for armaments, shaping technology is limited in some cases. Comparatively, radar absorbing materials (RAM) have become more important in stealth technology and are universally applied for their versatilities, low-cost, convenience of application and maintenance.But the receptivity of radar absorbing material mainly relies on the radar wave absorbent. Among the multitudinous absorbents, carbonyl iron becomes one of the most important radar absorbing materials by its outstanding performance. However, as a radar absorbent, the anticorrosion and impedance matching at the interface with air as well as the dispersiveness of the powder need further improvement The purpose of present paper is to generate outstanding performance of radar absorbing material based on carbonyl iron powder. Corresponding to the preparation, we obtained magnetic polymer micro-spheres contained Carbonyl iron particle capsule in the polymer shell.There are many approaches to prepare the magnetic polymer micro-spheres. Magnetic polymer micro-spheres were prepared with suspension polymerization method in this paper. The composite micro-spheres prepared by normal suspension polymerization, generally yielding microspheres larger than SO urn, is not suitable for the preparation of radar absorbing materials. So we devoted to prepare small size Carbonyl iron composite micro-spheres. Actually, we employed a novel suspension polymerization in preparation, In the special suspension system, monomer was separated from oil soluble initiator and Carbonyl iron particle, one organic phase contained oil soluble monomer, and initiator, Carbonyl iron particle as well as solvent belonged to another organic phase. Gelatin plays an important role during the preparation process. It made the two organic phases reacted with each other, ultimately forming a polymer shell on the surface. Monomer drops were the active units, they reacted on the surface of iron particle layer by layer. The size of product beads is smaller than the beads based on normal suspension polymerization.