Publications

In-situ Analysis of Local Electrochemical Corrosion Processes and Their Inhibition

No abstract is provided for this article.

Influence of Temperature on Anodic Oxide Growth on Aluminium During Anodizing at Applied Electrode Temperature

not Available.

The FIB/TEM method for the characterisation of rolled Al surfaces

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.

Dual-action smart coatings with a self-healing superhydrophobic surface and anti-corrosion properties

This work introduces a new self-healing superhydrophobic coating based on dual actions by the corrosion inhibitor benzotriazole (BTA) and an epoxy-based shape memory polymer (SMP).

Light through glass: The spectrum of Late Antique glass from Cyprus

In this paper we have studied by optical spectroscopy the 5th–7th century glass material from three early Christian sites in Cyprus: Yeroskipou, Maroni Petrera and Kalavasos Kopetra. The glasses could be grouped into six chemical types: Levantine 1, HLIMT, two types of HIMT (named HIMTa and HIMTb), Egypt 1 and HIT. This work presents the first extensive application of in situ absorption spectroscopy to ancient glasses. UV absorption edge, Fe2+ concentration and colour coordinates are optical parameters that help identifying glass composition because there exists a link between chemical groups and UV–vis–NIR spectral shapes. This allows to select samples for chemical analysis on the basis of diverging optical properties rather than using ad random or subjective naked-eye strategies groups. Furthermore, optical spectroscopy offers an insight into the redox conditions under which the glasses were melted. We also show why the common practice among glass archaeologists to associate certain colour to specific chemical compositions can lead to misinterpretation of the glass consumption.

Atmospheric plasma synthesis of metallic platinum nanoparticles for PEMFC technology using an organometallic-carbon solution nebulized in the post-discharge of an RF torch

No abstract is provided for this article.

Electrodeposition of Nickel from Deep Eutectic Solvents

No abstract is provided for this article.

Influence of the surface activation and local pitting susceptibility on the AC-electrograining of aluminium alloys

AC electrograining of aluminium is strongly influenced by the surface microstructure. The mechanical and electrochemical properties of the sub-surface present in aluminium alloys affect the electrochemical reactions that prevail during electrograining. Etching pre-treatment of aluminium removes intermetallics and rolled-in oxides; as a result, the attack on the aluminium substrate starts with the initial cycles of the electrograining process. Local electrochemical investigations show differences in corrosion and passivation properties between rolled-in oxides and clean surfaces. The interface between rolled oxides and aluminium matrix acts as a weak point for pit initiation.

The effect of anodic oxide chemistry and morphology on adhesion and durability in aerospace structural adhesive bonding

No abstract is provided for this article.

Corrigendum to “Monitoring atmospheric corrosion under multi-droplet conditions by electrical resistance sensor measurement” [Corros. Sci. 236 (2024) 112271]

Molecular Characterization of Multiple Bonding Interactions at the Steel Oxide–Aminopropyl triethoxysilane Interface by ToF-SIMS

Organofunctional silanes are applied as coupling agents between organic coatings and low carbon steel substrates to promote adhesion. Although the metal oxide-silane interface plays an important role in the performance of the entire overlying coating system, it remains challenging to obtain a clear understanding of the interfacial molecular bonding mechanism and its influence on adhesion. In this work, time-of-flight secondary ion mass spectrometry is used to study interfacial interactions between aminopropyl triethoxysilane (APS) and low carbon steel. APS is shown to bond to the steel substrate through silanol steel and amine-steel interactions, and coatings are cured at varying temperatures to evaluate the influence of curing on these different types of bonding interactions. Unambiguous evidence for hydrogen bond interactions between APS silanol groups and steel surface hydroxyl groups is provided for the first time in this work through deuteration of the steel substrate and allows to tackle long-lasting doubts about the most wide-spread bonding theory that has been postulated for silane adsorption on metals.

Eruption frequency and magnitude in a geothermally active continental rift: The Bora-Baricha-Tullu Moye volcanic complex, Main Ethiopian Rift

Many Quaternary silicic volcanoes in the Main Ethiopian Rift pose a potential risk due to the poorly known eruptive histories of the volcanoes in combination with a high population density. In this study we provide new constraints on the Late Pleistocene-Holocene eruptive history of the Bora-Baricha-Tullu Moye (BBTM) volcanic complex located in the central portion of the Main Ethiopian Rift (MER). BBTM constitutes three main silicic edifices (i.e. Bora, Baricha and Tullu Moye) and numerous smaller vents (including Oda and Werdi). Tephra deposits from these vents are several centimetres to meters in thickness in currently densely populated regions and where geothermal development is taking place. We present new field observations in addition to physical, petrographic, geochemical and geochronological data. BBTM experienced at least 27 explosive eruptions, of varying magnitude, in the last ca. 100 ky. The two oldest tephra deposits in our compiled stratigraphy are associated with large-magnitude, and possibly caldera-forming eruptions. The youngest of these (Meki) occurred at 107.7 ± 8.8 (2σ) ka, which makes it the youngest caldera-forming eruption identified in the Central MER so far. During the post-caldera stage, BBTM underwent at least 25 eruptions sourced from the Baricha (9 eruptions), Bora (3), Oda (8), Werdi (3) and Tullu Moye (2) edifices. The return period of explosive activity in BBTM is thus at least one moderate-to-large explosive eruption every 4000 yr. Well-exposed units have estimated eruption magnitudes (M) that are 4 to 5, while smaller-scale eruptions reach up to 2.5 and are exclusively preserved near the Tullu Moye vent. The tephra was dispersed up to 20 km from the volcanic complex suggesting that more than one hundred thousand people could be exposed to tephra fall and pyroclastic density current hazards from future of similar-magnitude eruptions in this area.

Characterisation of Pretreatment Processes Applied to Aluminium Alloys to be Coated with Organic Layers

It is well know that the natural oxide film which forms when an aluminium surface is exposed to the atmosphere is responsible for the high corrosion resistance of aluminium. This corrosion resistance can be improved by organic finishes such as paints or lacquers. Substrate pretreatments play in this case an important role in the protection behaviour of aluminium alloys. Table 1 gives the main conversion layer treatments. Table 1 Conversion layer treatments https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780367814113/e616ef33-3aa4-41ac-8de0-bee025e0067f/content/tab9_1.tif"/>

Hydrogen Evolution in Battery Electric Vehicle Coolants During Accidental Leakage: The Impact of Corrosion Inhibitors and Electrical Conductivity

Efficient thermal management is critical to the performance and acceptance of battery electric vehicles (BEVs). In the event of coolant leakage, contact between conventional water–glycol coolants and polarized battery components may induce hydrogen evolution via electrolysis, posing a serious safety hazard. This study investigates the impact of copper corrosion inhibitors and coolant electrical conductivity on hydrogen gas formation through linear sweep voltammetry (LSV) using copper electrodes. Results indicate that commonly used corrosion inhibitors—Tolyltriazole (TTZ), Benzotriazole (BTZ), and Sodium Mercaptobenzothiazole (MBT-Na)—do not significantly reduce hydrogen evolution, even in synergistic combinations. On the other hand, lowering the coolant electrical conductivity markedly decreased hydrogen evolution, with a linear reduction in cathodic current observed in low-conductivity coolants due to the reduced ionic mobility of the electrolyte. Low-conductivity BEV coolant (86 µS/cm) presented a cathodic current density 96% lower than a high-conductivity ICE coolant (2577 µS/cm) at the same overpotential. These findings suggest that optimizing coolant conductivity is a more effective mitigation strategy than relying on corrosion inhibitor formulations.

Surface temperature: A key parameter to control the propanethiol plasma polymer chemistry

In this work, the influence of the substrate temperature (Ts) on the chemical composition of propanethiol plasma polymers was investigated for a given set of plasma conditions. In a first study, a decrease in the atomic sulfur content (at. %S) with the deposition time (td) was observed. This behavior is explained by the heating of the growing film during deposition process, limiting the incorporation of stable sulfur-based molecules produced in the plasma. Experiments carried out by controlling the substrate temperature support this hypothesis. On the other hand, an empirical law relating the Ts and the at. %S was established. This allows for the formation of gradient layer presenting a heterogeneous chemical composition along the thickness, as determined by depth profile analysis combining X-ray photoelectron spectroscopy and C60 ion gun sputtering. The experimental data fit with the one predicted from our empiric description. The whole set of our results provide new insights in the relationship between the substrate temperature and the sulfur content in sulfur-based plasma polymers, essential for future developments.

Novel and self-healing anticorrosion coatings using rare earth compounds

Self-healing materials have the ability to repair themselves and recover functionality after degradation, damage and failure. This chapter reviews recent developments in self-healing protective coatings which contain rare earth-based inhibiting compounds for active corrosion protection of metals. These new ‘green’ inhibitors are being developed as substitutes for chromate-based inhibitors. Different types of organic, hybrid and metallic systems are considered, with particular emphasis on thin sol-gel based layers. The main strategies for encapsulation of RE inhibitors are also reviewed. Significant future effort is required to improve the properties of organic coatings and to explore new self-healing coating alternatives that allow controlled release of the inhibitor.

Corrosion Protection of Steel by Using ZnCoFe Alloy Coating (Replacement for Cadium Coating)

Zinc and Zinc alloys have been extensively used as a replacement for Cadmium (Cd) coatings. ZnCo and ZnFe alloys with higher amount of Cobalt and Iron are very difficult to achieve due to anomalism associated with these coatings. Anomalous ZnCoFe alloy is a relatively recent addition in the family of Zn alloys. In this paper the corrosion resistance of ZnCoFe alloys with higher amount of Co (>10%) and Fe (>1%) are examined and compared with the pure Zinc, Cadmium and ZnCoFe alloy with low alloying elements (i.e. 0.5%Co+1%Fe). It is found that an increase in amount of Co > 10 % accounts for a shift in the OCP to a level higher than Zn and in case of >20% shifts somewhere near to Cd yet remains electronegative to steel. The coating shows superior corrosion resistance, in terms of its sacrificial and barrier properties, as compared to Zn, Cd and ZnCoFe (0.5%Co+1%Fe).