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Microwave-absorbing samples were fabricated using carbon black powder, super-paramagnetic Zn0.8Ni0.2Fe2O4 nanoparticles dispersed in a SiO2 matrix, epoxy resin, and hardener. The paint was then coated onto a steel substrate. The effects of super-paramagnetic Zn0.8Ni0.2Fe2O4 nanoparticles content (0–1.75 wt%) and different coating thickness (1–2.5 mm) on microwave absorption ability in the X-band frequency range (8–12 GHz) have been studied. The results showed that paint sample containing only carbon black (20 wt%) and epoxy resin (80 wt%) expressed low microwave absorption ability at 10 GHz centered frequency (≈ 67% absorption percentage). The super-paramagnetic Zn0.8Ni0.2Fe2O4 nanoparticles strongly affected the microwave-absorbing ability. A sample of 1.5 wt% super-paramagnetic Zn0.8Ni0.2Fe2O4 nanoparticles content exhibited highest microwave absorption at 10 GHz centered frequency (≈ 99% power attenuation). Higher coating thicknesses (1–2.5 mm) led to greater microwave absorption and reached a very high absorption of 2 mm thickness (≈ 99% absorption percentage at 10 GHz centered frequency). [ABSTRACT FROM AUTHOR]

We investigated the influence of carbon materials on the properties of adhesives. With the aim of the development of conductive and mechanically improved adhesives, different types of multi-walled carbon nanotubes (MWNT), single-layer graphene, graphene nanoplatelets, graphite, and carbon black were dispersed into an epoxy adhesive. For inserting particles within the viscous matrices and to obtain homogenous and stable dispersions, two different methods namely a three-roll mill and a dual asymmetric centrifuge have been compared The results demonstrate that filling epoxies with carbon nanoparticles improves the conductivity differently. Measuring the electrical resistivity of MWNT-filled composites resulted in an electrical percolation starting underneath 0.1 wt.%. Further, with increasing the MWNT content, conductivity sharply increases. In contrast to the MWNT composites, other carbon nanoparticles require a higher filling content to reach similar values. With a filling ratio up to 17.0 wt.% for ACS graphene nanoplatelets 2–10 nm and the filling of 3.0 wt.% with MWNTs from Nanocyl, the lowest volume resistivities have been reached. [ABSTRACT FROM PUBLISHER]