We synthesized (ZnO nanoparticles)/polypyrrole (ZnO_NPs/PPy) hybrid nanocomposites and used them as additives in an epoxy paint to protect SAE 1020 carbon steel from corrosion. The nanocomposites were obtained by chemical polymerization of pyrrole in aqueous solution and sodium dodecyl sulfate solution containing dispersed ZnO nanoparticles. We characterized the nanoparticles by infrared absorption spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A large disparity in the distribution of ZnO particle sizes became evident from the TEM images, which also show the formation of hybrid nanocomposites consisting of polypyrrole coated ZnO nanoparticles. Electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) tests, which were performed on SAE 1020 carbon steel plates coated with epoxy and ZnO_NPs/PPy, have shown that epoxy paints have their efficiency as anticorrosive coatings significantly improved when ZnO_NPs/PPy hybrid nanocomposites are added to them.

AA7075 aluminum alloy is widely used for several high-technology applications for its high mechanical strength to weight ratio but is still the subject of several studies seeking a further increase in its mechanical properties. A commercial powder is used, either as-received or after ball-milling. Dense AA7075 samples are prepared in one step by Spark Plasma Sintering, at 550 °C with a holding time of 15 min and a uniaxial pressure of 100 MPa. No additional heat treatment is performed. Laser granulometry, X-ray diffraction and optical- and scanning electron microscopy show that both grain size and morphology are preserved in the dense samples, due to the relatively low temperature and short sintering time used. The samples prepared using the ball-milled powder exhibit both higher Vickers microhardness and transverse fracture strength values than those prepared using the raw powder, reflecting the finer microstructure.