Publications

Self-healing coatings with capsules containing healing agents have been developed for the corrosion protection of metal. In this paper, polyurethane capsules were synthesized under different conditions to examine the size and shape of capsules, and self-healing ability of coatings with capsules dispersed was examined after damaging the coated layer by scratching with a cutter blade. The size and shape of capsules depended on the concentration of chlorobenzene in cyclohexanone used as a solvent of prepolymer solution. The capsule formed with 70 % of chlorobenzene gave a self-healing capability to the coated layer by releasing the healing agent after damaging. The amount of glycerol added for the formation of the polyurethane capsule shell affected the self-healing ability of the coated layer. The coating with the capsule formed with small amounts of glycerol showed a high healing ability, while, with large amounts of glycerol, the self-healing ability was relatively low.

This research unravels the formation mechanism of a hybrid conversion treatment including the well-established Zr conversion coating with a silane-based organic additive and Cu-based inorganic additive. The deposition mechanism of this coating was investigated on the thermal oxide film of Advanced High Strength Stainless Steels (AHSSS). This coating has been characterized using advanced surface analytical techniques such as XPS, FEG-AES, GDOES, and ToF-SIMS. The results showed that the simultaneous presence of these two additives results in the formation of a donor-acceptor complex between amine groups and Cu ions. The final coating contains Cu oxide together with a Cu-aminosilane complex, Zr oxide deposited mainly around Cu oxide and the aminosilane layer on the outer surface.

For the characterisation of Al surfaces after thermo mechanical processing of rolled strips TEM is imperative. Especially cross-sectional TEM specimens highlight the multi-layered structures of the surface area. The specimen preparation of cross-sections is a critical step in TEM analysis. A common technique is ultramicrotomy, where a diamond knife is used to cut electron transparent slices. The major disadvantage of the method - especially in the case of aluminium - is the strong mechanical deformation resulting from cutting. Another technique is the conventional ion beam milling. In order to provide views of subsurface regions, the sample surfaces are initially glued together, then cut perpendicular to the sheet surface, mechanically thinned, cut to form disks, dimpled, and ion beam thinned. Here, a new method for preparing cross-sectional TEM specimens of aluminium surfaces is introduced: Focused Ion Beam thinning (FIB), which became a standard method for preparation in the semiconductor industry. This technique has the potential of introducing nearly no chemical and structural modifications in the specimen. TEM lamellae of equal thickness can be produced in less than two hours and the success rate is nearly 100%. As an example for this new preparation method the paper reports about a (S)TEM investigation of a FIB prepared specimen of the surface of an AlMg0.5 hot rolled strip.

High-efficiency low-cost field-installable 180deg-bend single-mode fiber (SMF) sockets are promising new fiber connector components that can facilitate network element footprint reduction and allow for more comfortable connector handling in the field. We present a novel type of small-form-factor 180deg coupling SMF socket component, yielding coupling losses between two side-by-side positioned fibers as low as 0.5 dB, making use of specially designed low bending loss hole-assisted fiber. The components are prototyped in a polymer using deep proton writing and show all the potentialities for low-cost fabrication in different types of plastics.

Detailed understanding of localised corrosion phenomena induced by inclusions in low-alloy steel is extremely critical as any corrosion-induced premature failure can potentially lead to a catastrophe. In particular, there is still ambiguity as to whether the localised corrosion initiation induced by non-metallic inclusions is an electrochemical process or a chemical process. Herein, the localised heterogeneous electrochemical mechanism of typical non-metallic inclusions–Al2O3, ZrO2-Ti2O3-Al2O3, and (RE)AlO3-(RE)2O2S-(RE)xSy – was investigated using scanning Kelvin probe force microscopy and current-sensing atomic force microscopy. The chemical stability of typical non-metallic inclusions was characterized by Pourbaix diagrams. The results indicate that the localised corrosion behaviour shows no correlation to the Volta potential difference between the non-metallic inclusions and the matrix. Moreover, the localised corrosion initiation process is mainly a chemical corrosion process rather than an electrochemical corrosion process. Thus, the applicability of Volta potential difference in predicating the preferential corrosion area in different system (conductive/nonconductive system) should be given full attention.

No abstract is provided for this article.

The influence of hot-stamping process on the corrosion properties of Al-Si coating on 22MnB5 steel was locally evaluated using a depth profiling approach combining GDOES and electrochemical micro cell. The results highlight the complexity of the system and the high dependence of the local galvanic series on the hot-stamping process. Due to iron diffusion from the steel substrate into the coating, the Al-rich layers presented active behaviour, whereas the initial coating condition showed a passive behaviour. Conversely, Fe/Si-rich sublayers acted as protective barrier for the steel substrate, as they show passive behaviour with nobler corrosion potentials and lower current densities.

No abstract is provided for this article.

Additives from lubricating emulsions used in the rolling step of aluminium plate production, are suspected to adhere to the surface and change the surface properties of the metal. The present study aims at investigating the feasibility of a Fourier transform laser microprobe mass spectrometer with external ion source to characterize the organic components at the metal surface. Special attention is given to the possible interactions between the additives and the aluminium. The experiments primarily involve model systems, consisting of aluminium with a thin coating of the individual components or of laboratory-made mixtures

For most bare Mg-based materials in aqueous media, an inductive behavior can be detected at the low frequencies electrochemical impedance spectroscopy (LF-EIS) measurement, which potentially can be associated with the non-stationarity of the system. The non-stationarity in EIS measurement leads to inaccurate acquisition of experimental data and, thus, misunderstanding of the electrochemical behavior of tested samples. To investigate the non-stationarity of EIS measurements on Mg-based materials in aqueous media, conventional EIS measurements are performed on pure Mg and several representative Mg alloys (AZ31, AZ91, AM50) in NaCl and Na2SO4 solutions. The results indicate that the impedance spectra of Mg-based materials in aqueous media is influenced by the internal non-stationarity of the Mg-electrolyte system and the external non-stationarity induced by EIS measurement. Multisine odd random phase EIS (ORP-EIS) measurements were performed to visualize the non-stationarity and non-linearity of the system. Moreover, the comparison of conventional and ORP-EIS results exhibits the difference between pseudo and real inductive behavior for the AZ31-NaCl system. Accordingly, the origin of the inductive behavior of Mg-based materials is discussed.

No abstract is provided for this article.

Electrochemical permeation tests are used to investigate the diffusion and trapping effects of hydrogen in a metal. For a quantitative and reliable evaluation of these features, the development of a numerical model is required. In the first paper of this series, we developed a model describing the hydrogen transport process in the Devanathan-Stachurski cell and evaluated the influence of the entry interface on the experimental results. Although many models have already been proposed for the description of the hydrogen diffusion in the Devanathan-Stachurski cell, none of them is including the simulations of the anodic side of the cell. In this paper, we present a new model representing the Devanathan-Stachurski cell. With this model, we are able to make a sensitivity analysis of all the parameters that play a role during the hydrogen diffusion process in iron alloys, comprising the adsorption, absorption, diffusion and desorption processes that the hydrogen undertakes in the sample mounted in the Devanathan-Stachurski cell. In particular, we found that the common assumption of constant zero concentration at exit side broadly accepted by researchers may not always reflect the real situation and the evaluation of the desorption process as often used today might be oversimplified. Certainly, the complexity of the desorption/oxidation is of high degree when Pd coating is not applied at the exit side. Consequently, the effect of the anodic electrolyte and the surface state at exit side should be considered as a significant element affecting the experimental results.

Schematically deciphering the electrochemical mechanism of the electrochromic NiO_x thin film based on the Li⁺-ion electrolytes.

In the restoration-conservation practice of medieval art masterpieces, such as the Holy Lady Shrine from Huy, knowledge about the techniques used to create and shape them is of major importance, especially when they concern the surface finishing treatments. This influences the selection of methods employed for the conservation-restoration process. This paper discusses the method and the materials that might have been employed to modify the colour of gilding on silver. Recipes for chemically modifying the colour of the gilded surface can be found in medieval texts and might have been used on the masterpiece discussed in this paper. This article gives an overview of technical instructions related to this topic and presents a method to interpret their contents in order to be able to implement them. It reports observations carried out during the implementation tests, such as information about the temperature, timing, and other important elements. It concludes with the visual and the colorimetric results on the samples after application of the tested recipes.

2,2,4,4,6,8,8‐Heptamethylnonane (HMN), a saturated branched hydrocarbon precursor, is deposited by means of atmospheric plasma DBD. Hydrophobic coatings starting from this precursor which is liquid at room temperature can be obtained. The degree of polymerization of the coating seems to be dependent on the amount of provided precursor. The coatings were characterized by FTIR, TOF‐SIMS, WCA, SE, and XPS. magnified image

Nanoporous silicon oxide templates formed by swift heavy ion tracks technology have been investigated. The influence of the heavy ion characteristics, such as type of ion, energy, stopping power and irradiation fluence on the pore properties of the silicon oxide templates, has been studied. Furthermore, the process of pore formation by chemical etching with hydrofluoric acid has been thoroughly investigated by assessing the effect of etchant concentration and etching time. The outcome of this investigation enables us to have precise control over the resulting geometry of nanopores arrays. As a result, guidelines for the creation of a-SiO2/Si templates with tunable parameters and general recommendations for their further application are presented.