Microwave absorption properties of fabric coated absorbing material using modified carbonyl iron power

The modified absorbing agent was prepared by depositing copper particles on carbonyl iron power (CIP) using a ultrasonic electroless copper plating method. Subsequently, a fabric coated absorbing material was fabricated on non-woven fabric coated absorbing dope containing 85 wt% modified CIP. Scanning electron microscope (SEM) and energy dispersion spectrum (EDS) were used to analyze the microstructure and components of modified CIP. Electromagnetic parameters of modified CIP and reflectivity losses of multi-layer fabric coated absorbing material were measured by a 3 cm waveguide system. The results showed that copper particles were successfully deposited on the surface of CIP. Compared with initial CIP, the values of the complex permeability and permittivity of modified CIP increased after CIP was disposed by ultrasonic electroless plating process, which resulted in a minimum reflection loss -8.43 dB with the thickness of about 2 mm in the frequency range of 8-12 GHz. Furthermore, non-woven fabric absorbing material has a reflection loss -26 dB with the matching thickness of 2.08 mm at 9.35 GHz. It was concluded that ultrasonic electroless copper plating process had great effects on increasing microwave absorption properties of CIP. Moreover, structure of non-woven fabric had a contribution to improve absorbing performance. In addition, because fabric used was light enough, monolayer non-woven fabric coated absorbing material (FCAM) had a low planar density about 0.2 kg/m².