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We investigated the corrosion properties and transpassive behavior of CrMnFeCoNi and CrCoNi multi‐principal element alloys (MPEAs) in a 0.1 M NaCl electrolyte at pH 12. By using SECM‐based tip substrate voltammetry (TSV) in combination with the chemical analysis of the electrolyte, we were able to differentiate between anodic metal dissolution and oxygen evolution in the transpassive range. Our investigations have shown that CrCoNi has a significantly higher corrosion resistance compared to CrMnFeCoNi. In the studied alkaline environment, a transpassive oxide film is formed on the surface of CrCoNi during secondary passivation. This transpassive oxide film appears to play a significant role in oxygen evolution, as the increase in TSV currents at the microelectrode coincides with the corresponding current density plateau of the voltametric current trace. The formation of the transpassive oxide film was not observed in previous studies conducted in acidic environments. Moreover, the alkaline electrolyte induced a positive hysteresis and mild pitting corrosion, in addition to intergranular corrosion, which was the sole corrosion process observed at acidic pH levels. These findings enhance the understanding of the processes governing the transpassivity of CrMnFeCoNi and CrCoNi MPEAs in alkaline environments and have potential implications for the development of application‐tailored corrosion‐resistant MPEAs. [ABSTRACT FROM AUTHOR]

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Multi‐principal element alloys (MPEAs) are gaining interest in corrosion and electrocatalysis research due to their electrochemical stability across a broad pH range and the design flexibility they offer. Using the equimolar CrCoNi alloy, we observe significant metal dissolution in a corrosive electrolyte (0.1 M NaCl, pH 2) concurrently with the oxygen evolution reaction (OER) in the transpassive region, despite the absence of hysteresis in polarization curves or other obvious corrosion indicators. We present a characterization scheme to delineate the contribution of OER and alloy dissolution, using scanning electrochemical microscopy (SECM) for OER‐onset detection, and quantitative chemical analysis with inductively coupled‐mass spectrometry (ICP‐MS) and ultraviolet visible light (UV/Vis) spectrometry to elucidate metal dissolution processes. In situ electrochemical atomic force microscopy (EC‐AFM) revealed that the transpassive metal dissolution on CrCoNi is dominated by intergranular corrosion. These results have significant implications for the stability of MPEAs in corrosion systems, emphasizing the necessity of analytically determining metal ions released from MPEA electrodes into the electrolyte when evaluating Faradaic efficiencies of OER catalysts. The release of transition metal ions not only reduces the Faradaic efficiency of electrolyzers but may also cause poisoning and degradation of membranes in electrochemical reactors. [ABSTRACT FROM AUTHOR]

Pressure ulcers can develop in bedridden or immobile patients which physiotherapists frequently encounter. Although physiotherapists receive training for preventing pressure ulcers, there is limited evidence of physiotherapists' knowledge level. Our study evaluated physiotherapists' pressure ulcer prevention knowledge. The level of knowledge for pressure ulcer prevention was inquired with the Turkish version of the Pressure Ulcer Prevention Knowledge Assessment Instrument (PUPKAI‐T). Two hundred and sixty‐five physiotherapists participated in our study. The median PUPKAI‐T total score ranged from 8 to 21. Only two physiotherapists (0.8%) got good points from the questionnaire. The highest score was Nutrition (Theme 4; 59.2%), and the lowest score belonged to the contact preventive interventions that reduce pressure/shearing (Theme 5; 26.7%). The question with the lowest success rate was the positioning question of Theme 5 (Question 2; 12.5%). In our study, physiotherapists' pressure ulcer prevention knowledge was evaluated with a relatively high number of participants compared to the literature. These results brought to mind that training programs that specifically emphasise techniques to prevent pressure ulcers and positioning manoeuvres to be organised increase the knowledge level of physiotherapists. [ABSTRACT FROM AUTHOR]

The application of characterization methods with high spatial resolution to the analysis of buried coating/metal interfaces requires the design and use of model systems. Herein, an epoxy‐like thin film is used as a model coating resembling the epoxy‐based coatings and adhesives widely used in technical applications. Spin coating is used for the deposition of a 30 nm‐thin bilayer (BL) composed of poly‐(ethylenimine) (PEI) and poly[(o‐cresyl glycidyl ether)‐co‐formaldehyde] (CNER). Fourier‐transform infrared spectroscopy (FTIR) results confirm that the exposure of coated AA2024‐T3 (AA) samples to the corrosive electrolyte solution does not cause the degradation of the polymer layer. In situ atomic force microscopy (AFM) studies are performed to monitor local corrosion processes at the buried interface of the epoxy‐like film and the AA2024‐T3 aluminum alloy surface in an aqueous electrolyte solution. Hydrogen evolution due to the reduction of water as the cathodic corrosion reaction leads to local blister formation. Based on the results of the complementary energy‐dispersive X‐ray spectroscopy (EDX) analysis performed at the same region of interest, most of the hydrogen evolved originates at the vicinity of Mg‐containing intermetallic particles. [ABSTRACT FROM AUTHOR]

The aim of this study is to develop polymeric thin films for corrosion protection of magnesium alloy AZ31. As polymer matrix, poly(4‐vinyl pyridine) (P4VP) is selected due to its semiconducting properties and protonic conductivity. Polyacrylic acid is tested as crosslinking layers to improve interfacial adhesion. The macroscopic corrosion properties of the multilayer coatings are investigated by means of electrochemical methods, such as linear sweep voltammetry and electrochemical impedance spectroscopy (EIS), in corrosive media simulating technical and biomedical applications. It is demonstrated that thin multilayer coatings can suppress the corrosion rates of magnesium alloys. To our best knowledge, this is the first demonstration of the use of P4VP as a conducting polymer film with protonic conductivity for corrosion protection of magnesium alloys. [ABSTRACT FROM AUTHOR]

Abtract: The initial attachment and subsequent biofilm formation of electroactive bacteria Shewanella putrefaciens CN32 was investigated to clarify the influence of organic conditioning layers. A selection of macromolecules and self‐assembled monolayers (SAMs) of different chain lengths and functional groups were prepared and characterized by means of infrared spectroscopy in terms of their chemistry. Surface energy and Zeta (ζ‐) potential of the conditioning layers was determined with contact angle and streaming current measurements. Among the studied surface parameters, a high polar component and a high ratio of polar‐to‐disperse components of the surface energy has emerged as a successful indicator for the inhibition of the initial settlement of S. putrefaciens on stainless steel AISI 304 surfaces. Considering the negative surface charge of planktonic S. putrefaciens cells, and the strong inhibition of cell attachment by positively charged polyethylenimine (PEI) conditioning layers, our results indicate that electrostatic interactions do play a subordinate role in controlling the attachment of this microorganism on stainless steel AISI 304 surfaces. For the biofilm formation, the organization of the SAMs affected the local distribution of the biofilms. The formation of three‐dimensional and patchy biofilm networks was promoted with increasing disorder of the SAMs. [ABSTRACT FROM AUTHOR]

Biofilm formation and microbially influenced corrosion of the iron‐reducing microorganism Shewanella putrefaciens were investigated on stainless steel surfaces preconditioned in the absence and presence of flavin molecules by means of XANES (X‐ray absorption near‐edge structure) analysis and electrochemical methods. The results indicate that biofilm formation was promoted on samples preconditioned in electrolytes containing minute amounts of flavins. On the basis of the XANES results, the corrosion processes are controlled by the iron‐rich outer layer of the passive film. Biofilm formation resulted in a cathodic shift of the open circuit potential and a protective effect in terms of pitting corrosion. The samples preconditioned in the absence of flavins have shown delayed pitting and the samples preconditioned in the presence of flavins did not show any pitting in a window of −0.3‐ to +0.0‐V overpotential in the bacterial medium. The results indicate that changes in the passive film chemistry induced by the presence of minute amounts of flavins during a mild anodic polarization can change the susceptibility of stainless steel surfaces to microbially influenced corrosion. [ABSTRACT FROM AUTHOR]

Stainless steel AISI 304 surfaces were studied after a mild anodic polarization for oxide growth in the presence and absence of two derivatives of vitamin B2 (riboflavin and flavin mononucleotide) that can be secreted by metal‐reducing bacteria and act as a chelating agent for iron species. The alterations in oxide chemistry were studied by means of surface‐sensitive techniques such as X‐ray photoelectron spectroscopy and time‐of‐flight secondary ion mass spectrometry analysis. The complementary electrochemical characterization revealed a preferential growth of an oxide/hydroxide iron‐rich film that is responsible for an altered pit initiation and nucleation behavior. These findings suggest that as the corrosion behavior is determined by the interplay of the chemical and electronic properties, only a mild anodic polarization in the presence of redox‐active molecules is able to alter the chemical and electronic structure of the passive film formed on stainless steel AISI 304. This helps to achieve a profound understanding of the mechanisms of microbially influenced corrosion (MIC) and especially the possible effects of the redox‐active biomolecules, as they may play an important role in the corrosion susceptibility of stainless steel surfaces. [ABSTRACT FROM AUTHOR]

The aim of this study is to develop nanometer‐thin epoxy‐based films on aluminium alloy AA2024‐T3 as a model coating system for high resolution corrosion studies. Spin coating was used for the layer‐by‐layer (LbL) deposition of poly‐(ethylenimine) (PEI) and poly([o‐cresyl glycidyl ether]‐co‐formaldehyde) (CNER) bilayers. The film chemistry and the cross‐linking process were characterized by means of Fourier‐transform infrared spectroscopy (FTIR). Ellipsometric data confirmed the linear increase of film thickness. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicate the improvement of the film barrier properties with increasing film thickness. Mapping of the topography and the volta potential was performed by means of scanning Kelvin probe force microscopy (SKPFM). The results indicate the presence of a homogeneous film structure, while the intermetallic phases can still be identified below the coating. The SKPFM analysis confirmed that the model films are suitable for investigation of corrosion processes at the coating/metal interface. [ABSTRACT FROM AUTHOR]

In situ photoelastic-modulated Fourier transform infrared reflection absorption spectroscopy has been applied for the investigation of interfacial stability of organothiol and organosilane monolayer films on nanocrystalline zinc oxide thin films. It has been shown that for octadecyltriethoxysilane films, exposure to high water activities results in physisorption of water in the cross-linked film. This high water activity at the interface leads to a reversible wet de-adhesion of the interfacial silanol groups from the ZnO surface. However, the organothiol seems to form a denser monolayer and a stable by S-Zn bond that is resistant to the competition with adsorbed water. The reversible attachment for cross-linked organosilanol films has been demonstrated for the first time by means of an in situ spectroscopic method on model ZnO surfaces. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Interfacial processes during the initial stages of SiOx-like plasma-polymer barrier coating deposition were investigated by means of polarization modulation infrared reflection-absorption spectroscopy, and the resulting effect on defect densities were studied by cyclic voltammetry. Octadecanethiol self-assembled monolayers on Au-film coated wafers served as sensor layers to investigate interface chemistry during the plasma deposition. Both the spectroscopic and electrochemical data revealed that a thin SiOCH interlayer could reduce oxidative degradation of the SAM during subsequent deposition of the SiOx barrier film from an oxygen-rich plasma phase. The present electrochemical investigation confirmed effective inhibition of interfacial oxidative degradation processes of an aliphatic polymer in the presence of a SiOCH interfacial layer. [ABSTRACT FROM AUTHOR]

Back Cover: Reactions at the substrate/film interface during the initial stages of SiOx like plasma‐polymer barrier coating deposition governs the interface chemistry and the resulting defect densities. A thin SiOCH interlayer could reduce oxidative degradation of the organic substrate during subsequent deposition of the SiOx barrier film from an oxygen‐rich plasma phase, resulting in a stable interface and improved film formation. Further details can be found in the article by Berkem Ozkaya et. al. on page 392. [ABSTRACT FROM AUTHOR]