Publications

Advances in the synthesis of porous microspheres and in their functionalization are increasing the interest in applications of alumina. This paper deals with coatings plasma deposited from 3‐aminopropyltriethoxysilane by means of dielectric barrier discharges on alumina porous microspheres, shaped by a vibrational droplet coagulation technique. Aims of the work are the functionalization of the particles with active amino groups, as well as the evaluation of their surface coverage and of the penetration of the coatings into their pores. A multi‐diagnostic approach was used for the chemical/morphological characterization of the particles. It was found that 5 min exposure to plasma discharges promotes the deposition of homogeneous coatings onto the microspheres and within their pores, down to 1 μm.

Silane coating is a metal surface pre-treatment introduced as a replacement for chromium treatments. It is supposed to be suited for various metals, including aluminium, steel and galvanised steel. Good corrosion performance has been assigned to these hybrid organic–inorganic thin film deposition systems. The silane molecules contain SiOC n H(2n+1) groups, which after hydrolysis into reactive silanol groups SiOH form a covalent bonded layer on the metal surface. Curing of these films is considered essential for corrosion protection; during heat treatment, condensation of unreacted silanol groups in the film result in the formation of a SiOSi network with enhanced barrier properties. This contribution gives a chemical and morphological characterisation, obtained with spectroscopic ellipsometry (SE), of BTSE silane coated aluminium as a function of curing. Further, with thermal gravimetric analysis combined with mass spectroscopy (TGA-MS), the mechanism and kinetics of the curing process are explained, and the resulting barrier properties are measured using electrochemical impedance spectroscopy (EIS).

No abstract is provided for this article.

No abstract is provided for this article.

We use ambient-pressure X-ray photoelectron spectroscopy (APXPS) to study chemical changes, including hydroxylation and water adsorption, at copper oxide surfaces from ultrahigh vacuum to ambient relative humidities of ∼5%. Polycrystalline CuO and Cu2O surfaces were prepared by selective oxidation of metallic copper foils. For both oxides, hydroxylation occurs readily, even at high-vacuum conditions. Hydroxylation on both oxides plateaus near ∼0.01% relative humidity (RH) at a coverage of ∼1 monolayer. In contrast to previous studies, neither oxide shows significant accumulation of molecular water; rather, both surfaces show a high affinity for adventitious carbon contaminants. Results of isobaric and isothermic experiments are compared, and the strengths and potential drawbacks of each method are discussed. We also provide critical evaluations of the effects of the hot filament of the ion pressure gauge on the reactivity of gas-phase species, the peak fitting procedure on the quantitative analysis of spectra, and rigorous accounting of carbon contamination on data analysis and interpretation. This work underscores the importance of considering experimental design and data analysis protocols during APXPS experiments with water vapor in order to minimize misinterpretations arising from these factors.

The sol-gel synthesis process is a versatile method used to produce a wide diversity of materials and is being increasingly used as a surface modification method to alter porosity, wettability, catalytic activity, biocompatibility and corrosion performance of underlying substrates. Silane sol–gel films deposited on aluminium and aluminium alloys have been widely studied as chemical conversion coatings and as coupling agent between the substrate and organic layers. This study set out to investigate the effect of the surface chemical treatment prior to sol-gel application on the interfacial adhesion properties of a hybrid sol-gel film. Different surface pre-treatments, including two abrasive treatments and three chemical surface pre-treatments were used and their effect on surface chemistry and surface roughness was assessed. Surfaces were characterized by scanning electron microscopy, x-ray photoelectron spectroscopy, roughness measurements and static contact angles. Cerium nitrate loaded hybrid sol-gel films were deposited and adhesion on commercially pure aluminium was evaluated using pull-off testing. Statistical analysis revealed that, although highest adhesion values were obtained on rougher surfaces, the strongest correlation exists between the surface hydroxyl fraction and adhesion strength.

This work aims to clarify the impact of convection, generated within an electrolyte droplet during evaporation, on the distribution of Al ( OH ) 3 in the CFRP-AA2024 system. Both Finite Element and experimental approaches were employed to determine whether convection is significant or negligible. By coupling the Navier–Stokes and Nernst–Planck equations with appropriate geometric and boundary conditions, the transient distribution of corrosion products was numerically tracked. The results showed that Al ( OH ) 3 preferentially deposits on the CFRP surface, a pattern absent when convection is excluded. Experiments confirmed that internal convective currents can transport the Al ( OH ) 3 compound, aligning with the numerical predictions.

Silane and silane-like films were deposited from bis-1,2-(triethoxysilyl)ethane by vacuum and atmospheric plasma onto aluminium. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used for probing the aluminium/plasma polymer film interface. An AlOSi+ fragment was identified at nominal mass m/z =70.9539amu, indicating a strong chemical interaction (formation of a covalent bond) at the substrate/film interface. Until now, this strong silane–aluminium interaction has never been observed in plasma polymer BTSE films. Ageing tests in an ultrasonic water bath combined with X-ray photoelectron spectroscopy measurements allowed to indirectly confirm good adhesion, and therefore the formation of a chemical bond at the interface.

No abstract is provided for this article.

not Available.

Deterioration of concrete structures, together with corrosion of reinforcing steel due to the action of microorganisms, is known as Microbiologically Induc