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Recently, lubricant-infused surfaces (LIS) have emerged as a prominent class of surface technology for antifouling, anti-icing and anticorrosion applications. However, long-term corrosion exposure and mechanical damages may deteriorate the practical performance of LIS during application. In this study, a robust LIS was fabricated by the vacuum impregnation of mineral oil into anodized aluminum oxide (AAO) nanochannels with a depth of 50 μm. The impregnation of the lubricant through the entire depth of the high-aspect-ratio nanochannels was visualized under cryo-scanning electron microscopy (cryo-SEM) and also confirmed by weight gain measurements. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests showed that the lubricant stored in the deep nanochannels of LIS can provide excellent corrosion protection during long-term immersion. Furthermore, the as-prepared LIS demonstrated superior resistance to mechanical damage due to a self-healing effect by the lubricant. As shown by cryo-SEM observation and PDP tests, the micro-cracks formed on the LIS can be instantaneously repaired by the in-flow of the oil from the surrounding surface. In the tribological tests, the LIS also presented high wear resistance and superior mechanical durability.

Two different methods were followed to improve the adhesion and durability of the adhesion of a commonly used epoxy coating on an aluminium substrate. The first method was by application of a thin polymeric layer, having a thickness of around 10nm, on the aluminium substrate prior to application of the epoxy coating. The functional groups in the polymers were chosen so as to be capable of chemisorption to the oxide surface and should also to be capable of being involved in the curing reaction of the epoxy resin. These polymers were poly(acrylic acid) (PAA), poly(ethylene-alt-maleic anhydride) (PEMah) and poly(vinyl phosphonic acid) (PvPA). An investigation of the interphasial region between the epoxy coating and the aluminium substrate in the final cured system showed that the polymeric layers were indeed involved in the curing reaction with the epoxy. For the poly(ethylene-alt-maleic anhydride)-based system, this resulted in the formation of a cured, mixed poly(ethylene-alt-maleic anhydride)/epoxy interphasial region between coating and substrate while for the two other polymers, a weakly cured interphasial region was formed. The second method of adhesion and durability improvement was by hydration of the aluminium substrates, performed by immersion in boiling water. This procedure results in the formation of a porous pseudoboehmite oxyhydroxide layer. The epoxy coating was found to be capable of fully penetrating into the layer. The adhesion of the epoxy coatings was tested initially and after exposure to 40°C water and 40°C 5% acetic acid. The poly(ethylene-alt-maleic anhydride)-based system resulted in a very good initial adhesion and durability in presence of water for the epoxy coating, while the systems based on the other two polymers did not. The pseudoboehmite-based system also resulted in very good initial adhesion and durability in the presence of water. None of the improved systems were, however, found to be able to withstand 40°C 5% acetic acid and showed severe corrosion underneath the epoxy coating.

In the present paper, a shape-memory polyurethane (SMPU) film consisting of a two-segmented block co-polymer is presented as a novel organic coating for the protection of metals against corrosion. When the coating is damaged, a physical self-healing and consequent recovery of the barrier properties are induced after an increase of the temperature. Indeed, thermal treatment leads to the relaxation of the soft matrix in the polymer and subsequent coverage of the damaged area. The scanning vibrating electrode technique (SVET) is employed to visualize local variations of the electrochemical activity in the damaged area of the SMPU coating, proving that the physical-repairing of the film during the thermal treatment leads to a recovery of the protective properties of the coated system. By using laser scanning confocal microscopy (LSCM), observation of the coating defect before and after the thermal healing allowed to establish the efficiency of the polymer to cover the coating defect qualitatively. Complementary experiments using dynamic mechanical analysis (DMA) allowed to study the mechanical properties of the co-polymer under a gradient of temperature and to prove its stability during the healing treatment.

We present the use of femtosecond laser ablation for the removal of monolayer graphene from silicon-on-insulator (SOI) waveguides, and the use of oxygen plasma etching through a metal mask to peel off graphene from the grating couplers attached to the waveguides. Through Raman spectroscopy and atomic force microscopy, we show that the removal of graphene is successful with minimal damage to the underlying SOI waveguides. Finally, we employ both removal techniques to measure the contribution of graphene to the loss of grating-coupled graphene-covered SOI waveguides using the cut-back method. This loss contribution is measured to be 0.132 dB/μm.

Atomic layer deposition (ALD) is a vapor phase technique that is able to deposit uniform, conformal thin films with an excellent thickness control at the atomic scale. 18 nm thick Al2O3 and TiO2 coatings were deposited conformaly and pinhole-free onto micrometer-sized Cu powder, using trimethylaluminum and tetrakis(dimethylamido)titanium(IV), respectively, as a precursor and de-ionized water as a reactant. The capability of the ALD coating to protect the Cu powder against corrosion was investigated. Therefore, the stability of the coatings was studied in solutions with different pH in the range of 0–14, and in situ raman spectroscopy was used to detect the emergence of corrosion products of Cu as an indication that the protective coating starts to fail. Both ALD coatings provide good protection at standard pH values in the range of 5–7. In general, the TiO2 coating shows a better barrier protection against corrosion than the Al2O3 coating. However, for the most extreme pH conditions, pH 0 and pH 14, the TiO2 coating starts also to degrade.

No abstract is provided for this article.

Combinatory localized electrochemical cell and glow discharge optical emission spectrometry (GDOES) measurements were performed to obtain a thorough in depth electrochemical characterization of an aluminum brazing sheet. By defining electrochemical criteria i.e. breakdown potential, corrosion potential, cathodic and anodic reactivities, and tracking their changes as a function of depth, the evolution of electrochemical responses through out the material thickness were analyzed and correlated to the corresponding microstructural features. Polarization curves in 1wt% NaCl solution at pH 2.8 were obtained at different depths from the surface using controlled sputtering in a glow discharge optical emission spectrometer as a sample preparation technique. The anodic and cathodic reactivity of the top surface areas were significantly higher than that of the bulk, thus indicating these areas to be more susceptible to localized attack. Consistent with this, optical microscopy and scanning electron microscope analysis revealed a relatively high density of fine intermetallic and silicon particles at these areas. The corrosion mechanism of the top layers was identified to be intergranular and pitting corrosion, while lower sensitivity to these localized attacks were detected toward the brazing sheet core. The results highlight the successful application of the electrochemical depth profiling approach in prediction of the corrosion behavior of the aluminum brazing sheet and the importance of the electrochemical activity of the outer 10μm in controlling the corrosion performance of the aluminum brazing sheet.

A few decades ago, heritage scientists and art historians started to study the ancient surface colouring techniques of metal art pieces. Colouring of copper and silver has already been broadly studied but no works on gold have been reported yet. This knowledge can be very important for art and technology history, conservation–restoration and surface sciences. This paper contributes to the investigation of the oldest recipe known so far to colour fire gildings. The chosen model samples, the mixture and the application of the recipe have been summarised by referring to the ancient writings known as the Arab and Syrian Alchemist Collection of M. Berthelot. The main aim of this research is to study the colour change obtained by applying the above mentioned recipe, and to identify the processes involved during this colour change. Digital imaging and scanning electron microscopy in combination with colorimetric measurements and elemental analysis have been performed to characterise the colour change and to identify its origins.