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Abstract: The electromagnetic (EM) properties of hybrid poly(ɛ-caprolactone)/carbon nanofiber films and electrospun mats at microwave frequencies (8.2–12.4GHz) were assessed by means of wave guide measurements. It was found that, on equal composition, the two systems present very different permittivities, that in the case of electrospun mats is far lower than that of films. These results are explained in view of the different microstructures. In particular, the massive presence of porosity is demonstrated to be the major parameter affecting the EM properties of mats. Shielding effectiveness was evaluated and was found to be poor for both systems, despite the relative large amount of conductive nanofiller. This results was attributed, in the case of films, to the presence of multiple reflections among CNF, while in the case of mats to their porous microstructure that let the waves easily pass through. [Copyright &y& Elsevier]

Abstract: Fibrous poly(vinyl alcohol)/zirconia and poly(vinyl alcohol)/alumina nanohybrids were obtained by electrospinning technique, the applied voltage ranging between 12 and 16kV. The actual nanofiller content ranged between 2 and 9wt%. Electrospun nanohybrids consisted of uniform fibers free of defects. The average fiber diameter was around 600nm for all electrospun mats. Nano and/or submicrometric ceramic agglomerates were observed onto and inside the overall polymeric fibers. Nanohybrid mats containing the highest amounts of nanoparticles showed a significant reduction of crystallinity. All electrospun nanohybrids evidenced improved mechanical properties with respect to the neat PVA mat. The tensile modulus of PVA/Al2O3 and PVA/ZrO2 mats reached 350±40MPa and 190±55MPa, respectively, the value for the neat PVA being 90±20MPa. [Copyright &y& Elsevier]

Abstract: Reactive plasma spraying (RPS) technology has been used to produce high thickness (>100μm) films of composite Ti–TiN–Ti x N y coatings. Reactively sprayed coatings obtained from SP700 (Ti–4.5Al–3V–2Mo–2Fe) and Ti6242 (Ti–6Al–2Sn–4Zr–2Mo) powders, deposited onto flat substrates of Ti–6Al–4V, have been investigated. X-ray diffraction (XRD) and micro-hardness measurements have been used to characterize the crystallographic features and differences between the hardness of cross-section and surface. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques have been used to determine the morphology and surface chemical composition of the coatings. Back-scattered electron imaging has revealed the distribution of Ti and TiN in the composite material. Obtained results evidenced a sharp interface between the coating and substrate in terms of the profile of chemical composition. The presence of unmelted Ti particles as well as the formation of nitrides was observed. [Copyright &y& Elsevier]