چكيده به لاتين
With the growing use of electromagnetic wave-based devices and the consequent increase in electromagnetic pollution, there has been a rising interest in the research, development, and manufacture of radar wave absorbers that operate within the microwave frequency spectrum. These absorbers are used in a variety of applications, including microwave darkrooms, electromagnetic wave interference coatings, stealth technology, and biological protectors. Electromagnetic wave absorber coatings use materials with dielectric or magnetic properties. When electromagnetic waves interact with these coatings, they are weakened and absorbed as the coating is heated.
In this study, the impact of pyrrole coating and increased reduced graphene oxide on the structure of a ternary composite consisting of barium hexaferrite, barium titanate, and reduced graphene oxide was investigated. The initial step involved synthesizing barium hexaferrite using the sol-gel combustion method. The formation of barium hexaferrite nanoparticles was then confirmed through various analyses. Subsequently, each of the powders—barium hexaferrite, barium titanate, and reduced graphene oxide—was coated with polypyrrole using in-situ polymerization. To investigate the effect of the coating on the properties of the produced composite, a sample of the three-component composite without the coating was also examined. All samples were synthesized with a thickness of 3 millimeters on a polyurethane substrate.
In this research, various samples were examined, and it was found that the sample containing a 12% reduced graphene oxide coating with polypyrrole exhibited the highest reflection loss of approximately -31 decibels at a thickness of 3 millimeters and within the 9.5 gigahertz range. With an increase in the reduced graphene oxide coating with polypyrrole, the values of permittivity initially decreased and then increased. The increase in reduced graphene oxide led to an increase in dipole moment concentration, which is a factor contributing to the increase in permittivity. Therefore, an increase in absorption was observed in this sample.
In the synthesized samples in this study, the samples containing polypyrrole coating showed higher real and imaginary values of permittivity compared to the sample without polypyrrole coating due to the conductivity properties of the polymer and the presence of electric dipoles in the sample structure. With an increase in permittivity in these samples, the samples with polypyrrole coating obtained higher values of reflection loss. The increase in the protection efficiency percentage in the sample containing a 12% reduced graphene oxide coating with polypyrrole compared to the sample without polypyrrole coating was estimated to be from 58.7% to 93.2%.
