Microwave absorption properties of carbonyl iron-based paint coatings for military applications

The paper explores the possibilities of using carbonyl iron in the form of a powder for the manufacture of radar-absorbing paints – reducing the radar signature of the objects that they cover. The attenuation values in the range of 4–18 GHz for various coating thicknesses, ranging from 0.5 to 2.00 mm with 0.5 mm increment, and for different absorber content −75% and 80%, as well as the use of two different binders in the form of epoxy resins with hardeners, were investigated. For the frequency of 18 GHz and a 1.5 mm thick coating with a 75% absorber content, Epidian 112 resin and Saduramid 10/50 hardener used as a binder, and the maximum attenuation level obtained equalled 20.2 dB at 16 GHz. Additionally, the absorber particle size ranging from 3 to 4 μm and its higher mass content resulted in achieving the reflection loss above −12 dB in the entire 8–12.5 GHz range for layers between 1- and 1.5 mm thickness. The qualitative assessment of the tested samples in the context of camouflage in the radar range was also performed, using statistical analysis.