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3C-SiC single crystals have been initially irradiated in the nuclear energy loss regime with 100keV Fe ions to fluences ranging from 4×1013 to 4×1014 cm− 2 (i.e. 0.07–0.7dpa). RBS/C measurements indicate that SiC rapidly becomes amorphous (at ∼0.4dpa). Two damaged SiC crystals exhibiting a different defective structure have been subsequently irradiated in the electronic energy loss regime with 870MeV swift heavy (Pb) ions (SHIs) up to a fluence of 4×1013 cm− 2. Initially fully amorphous SiC layers showed a decrease in size after SHI irradiation with a recrystallization occurring at the amorphous–crystalline interface. On the contrary, partially amorphous crystals for which onset of amorphization just initiated at the damage peak recovered over the entire damage thickness. Variation of amorphous thickness or disorder level has been monitored as a function of Pb ion fluence, which allowed deriving recrystallization kinetics. Data have been fitted with the direct-impact model and recrystallization cross-sections and threshold values for recovery have been determined for both types of initially defective structures. Differences are qualitatively discussed in terms of nature and density of irradiation defects. All experimental trends have been successfully reproduced by molecular dynamics simulations that mimicked thermal spikes induced by SHIs. [ABSTRACT FROM AUTHOR]

Nanostructured films offer the ability of modifying surface properties, even more, when they can generate layers with controlled porosity. The lower implicit integrity of these (multi)layers when compared to their compact counterparts, hinders the attainment of electron-transparent sections of submicron thicknesses (lamellae), which becomes one of the main reason for the scarcity of studies thorough (scanning-)transmission electron microscopy ((S)TEM). Aware of this opportunity, this report provides an overview of the possibilities offered by the application of a variety of (S)TEM techniques for the study of nanostructured and porous photonic surfaces. A few working examples are presented to illustrate the type of information that can be obtained in the case of mesoporous films prepared either by at oblique angles physical processes as well as nitride nanowire arrays prepared by epitaxy methods. It will be demonstrated that this approach enables the realization of several pioneering works, which are essential to complete the characterization of such porosity-controlled coatings. Topics as diverse as the preparation of electron-transparent specimens and the advanced characterization of their structures, morphologies, interfaces and compositions are addressed thanks to the implementation of new breakthroughs in (S)TEM, which allow to obtain high-resolution imaging, spectroscopies, or tomography, at both microscopic and nanoscopic levels. Finally, establishing (S)TEM as a reference tool for the advanced structural, chemical and morphological characterization of porous nanostructured skins, will open new horizons, providing better and new insights and thus allowing the optimization of the fabrication and design of such architectures. [Display omitted] • Advanced (S)TEM studies of porous nanostructured coatings at micro-and nanoscale • Preparation of electron-transparent lamellae of porous layers of diverse materials • Crystal structure surveys by HRTEM and STEM-iDPC methods • Chemical compositional analyses by STEM-EDX and STEM-EELS • 3D reconstructions and porosity/depth profiles by STEM-HAAF tomography [ABSTRACT FROM AUTHOR]

Abstract: Thin films of AlO x N y were deposited by magnetron sputtering in a wide composition range. Different structures and morphologies were observed, depending on the composition and bonding states, which opened the possibility to tailor the properties of this oxynitride system between those of pure Al and those of nitride and oxide films. In a wide range of stoichiometries, one can report the formation of nanocomposite porous films, where Al nanoparticles are dispersed in an amorphous matrix of AlO x N y . The electrochemical behaviour of the films was studied in isotonic NaCl solution. It was observed that the pitting potential characteristic of aluminium disappears with the incorporation of oxygen and nitrogen in the films, being replaced by a smooth current increase. Electrochemical impedance spectroscopy performed during 35 days showed that the corrosion resistance of the films steadily increases. The unusual optical reflectance profile of some films is maintained after immersion for several months. [Copyright &y& Elsevier]