Synthesis of magnetic nanometal oxides for electromagnetic radiation absorbing paints

In our daily life, we overexposure to electromagnetic waves from mobile phones, base stations, computers, household electrical appliances and devices located around us and continuously emitted electromagnetic waves. In addition, high-tech diagnostic and treatment devices used in the medical and scientific world are likewise an electromagnetic wave source. Consequently, shielding of electromagnetic waves is vitally important for human health. On the other hand, it is also very important for the defense industry of the countries due to the security needs such as the protection of the computers where the state information are stored and the prevention of listening. In this study, magnetic nanoparticles of MFe2O4 spinel ferrite structures were synthesized by co-precipitation method. The structural and morphological properties of the synthesized magnetic nanoparticles were characterized by FT-IR, XRD and TEM measurements as well as their magnetic properties were characterized by VSM measurements. The electromagnetic shielding properties of magnetic nanoparticles in the 3.30-12.4 GHz band intervals were determined by the waveguide method. It was determined that pure magnetic nanoparticles had low EM shielding efficiency but increased shielding efficiency due to conductive material such as multi-walled carbon nanotube (MWCNT). The shielding efficiency was optimized by varying the ratio of magnetic nanoparticle/MWCNT in the composite and the best shielding efficiency was obtained with 50:10 [PEG:CoMNP(1:1)]:MWCNT composite. It has also been determined that the coating thickness for shielding efficiency is significant and detected a reduction performance of up to 99% of incoming radiation with the samples coated with thickness of 6x120 micron. The optimized magnetic composite mixture was blended with a water-based wall paint at a ratio of 1:2 and then the EM shielding property of the wall paint in the 8.2-12.5 GHz range was measured. 84% of incoming radiation in this range was determined to shield.