Preparation and Characterization of Graphene Oxide/Polyaniline/Carbonyl Iron Nanocomposites

Nano coatings for anti−corrosion and electromagnetic wave absorbing can simultaneously implement the functions of assimilating electromagnetic waves and reducing the corrosion of materials caused by corrosive environments, such as seawater. In this work, a composite material for both electromagnetic wave absorption and anti−corrosion was prepared by an in−situ chemical oxidation and surface coating method using carbonyl iron powder (CIP), graphene oxide (GO) and aniline (AN). The synthesized composite material was characterized by scanning electron microscopy (SEM), infrared spectroscopy (FT−IR) and XRD. The carbonyl iron powder−graphene oxide−polyaniline (CIP−GO−PANI) composite material was used as the functional filler, and the epoxy resin was the matrix body for preparing the anticorrosive wave−absorbing coating. The results show that CIP had strong wave−absorbing properties, and the anti−corrosion property was greatly enhanced after being coated by GO−PANI.

Morphological Analysis of Unstructured and Prestructured Magneto-rheological Elastomer

By providing or not put on a magnetic flux, a magneto rheological (MR) elastomer becomes a very powerful and advanced smart material that could be twisted and responded hurriedly in relations of mechanical strength. They are elastomer materials with embedded iron elements in an elastomer environment. Isotropic(unstructured) and anisotropic(prestructured) MR elastomers are categorized built on the submission of a magnetic flux during in the fabrication process. The scattering of magnetizable elements in the medium of an elastomer is well defined and arranged by kind. Scanning Electron Microscopy(SEM) had revealed their shape. They should be employed in a variability of solicitations payable to their improved morphological characteristics, such as pulsation absorbers, isolators, seismic devices, and so on. Keywords: Smart material, magneto rheological elastomer, carbonyl iron particles, morphology, scanning electron microscopy

Enhanced Electromagnetic Wave Absorption Properties of Ultrathin MnO2 Nanosheet-Decorated Spherical Flower-Shaped Carbonyl Iron Powder

In this work, spherical flower-shaped composite carbonyl iron powder@MnO2 (CIP@MnO2) with CIP as the core and ultrathin MnO2 nanosheets as the shell was successfully prepared by a simple redox reaction to improve oxidation resistance and electromagnetic wave absorption properties. The microwave-absorbing properties of CIP@MnO2 composites with different filling ratios (mass fractions of 20%, 40%, and 60% after mixing with paraffin) were tested and analyzed. The experimental results show that compared with pure CIP, the CIP@MnO2 composites have smaller minimum reflection loss and a wider effective absorption bandwidth than CIP (RL < −20 dB). The sample filled with 40 wt% has the best comprehensive performance, the minimum reflection loss is −63.87 dB at 6.32 GHz, and the effective absorption bandwidth (RL < −20 dB) reaches 7.28 GHz in the range of 5.92 GHz–9.28 GHz and 11.2 GHz–15.12 GHz, which covers most C and X bands. Such excellent microwave absorption performance of the spherical flower-like CIP@MnO2 composites is attributed to the combined effect of multiple beneficial components and the electromagnetic attenuation ability generated by the special spherical flower-like structure. Furthermore, this spherical flower-like core–shell shape aids in the creation of discontinuous networks, which improve microwave incidence dispersion, polarize more interfacial charges, and allow electromagnetic wave absorption. In theory, this research could lead to a simple and efficient process for producing spherical flower-shaped CIP@MnO2 composites with high absorption, a wide band, and oxidation resistance for a wide range of applications.

Study on frequency selective/absorption/reflection multilayer composite flexible electromagnetic interference shielding fabric

Three kinds of electromagnetic functional materials, frequency selective surface, carbonyl iron coated absorbing fabric and conductive woven fabric, were laminated to filter, absorb and reflect electromagnetic waves. Through equivalent circuit analysis, the frequency selection characteristics and the correlation between the shape and size of the periodic structure of cross-shaped and Jerusalem-shaped frequency selective surfaces were studied. It is found that frequency selective surfaces can reduce the transmission coefficient of carbonyl iron coated fabric at the resonance point, so that the working frequency band of the composite shielding material can be controlled and adjusted. The stacking order has no effect on the frequency selective surface/frequency selective surface double-layer materials, but influence the transmission coefficient of composite materials with frequency selective surface superimposed carbonyl iron coated fabric and/or conductive woven fabric. Among all samples, the transmission coefficient of Jerusalem-shaped/carbonyl iron coated fabric-3/conductive woven fabric has the most strong shielding effect, which is up to −51.72 dB at 10.48 GHz. It is proved that using flexible fabric as the matrix and compounding materials with different electromagnetic functions is an effective method to realize high efficiency and adjustable electromagnetic shielding ability.