Investigation on magnetic and microwave behavior of magnetite nanoparticles coated carbon fibers composite

Radar absorbing materials, i.e. magnetite (Fe3O4) coated carbon fibers (MCCFs) were fabricated by electro-deposition technique. Black-colored single spinel phase Fe3O4 nanoparticles was easily synthesized by hydrothermal method using reduction of a Fe (III) - Triethanolamine complex in an aqueous alkaline solution at 60-80 ◦C. Uniform and compact Fe3O4 films were fabricated on nitric acid treated carbon fibers. A correlation between magnetic and absorption properties of specimens was made. It was found that the deposition time, and the sequences of the coating process have a significant effect on the reflection loss characteristics of the MCCFs. On the other hand, the temperature of the coating process affects strongly the composition of the thin film. MCCFs prepared at 80 ◦C possesses a much higher loss factor than the one prepared at 60 ◦C. The morphology, phases in the coating layer, magnetic properties and absorption behaviors of the MCCFs were examined using FESEM, XRD, permagraph, vector network analyzer (VNA), respectively. The highest reflection loss that is −10 dB at 12.27 GHz was observed in the sample deposited for four minutes. It was also found out that a uniform deposition layer can be observed in the sample deposited in three steps in which each step takes four minimums.