Corrosion is the main factor limiting lifetime of metallic materials, and a fundamental understanding governing mechanism surface processes difficult to achieve since thin oxide films at metal-liquid interface passivity are notoriously challenging study. In this work, combination synchrotron-based techniques electrochemical methods used investigate passive film breakdown Ni-Cr-Mo alloy, which in many industrial applications. This alloy found be active toward oxygen evolution reaction (OER),...

Various mechanisms have been proposed for hydrogen embrittlement of duplex stainless steel, but the causation hydrogen-induced material degradation has remained unclear. This work shows that phase instability (decomposition) austenite and ductile-to-brittle transition ferrite precedes embrittlement. In-situ diffraction measurements revealed Ni-rich sites decompose into metastable hydrides. Hydride formation is possible by increasing chemical potential during electrochemical charging low...

The surface chemistry and thickness of the native oxide, hydroxide, modified sub-surface layer three Ni superalloys (alloy 59, 625, 718) were determined by synchrotron X-ray Photoelectron Spectroscopy (XPS) Reflectivity (XRR). Taking advantage radiation techniques, a procedure for normalizing photoelectron intensity was employed, which allowed accurate quantitative analysis revealing total oxide all samples 12–13 Å, hydroxide 2–3 alloy 20–35 Å. results compared to structural atomic models...

The passive film stability on stainless steel can be affected by hydrogen absorption and lead to microstructure embrittlement. This work shows that the of results in surface degradation due oxide reduction ionic defect generation within film, which decomposes eventually vanishes. provides a barrier entering hydrogen, but when is formed, atomic infuses into lattices austenite ferrite phases, causing strain evolution, as shown synchrotron x-ray diffraction data. vacancy concentration hence...

To investigate aging effect on the passive film of Ni23Cr15Mo and Ni22Cr9Mo3Nb, synchrotron-based X-ray photoelectron spectroscopy (XPS) was used to analyze structure composition air-formed alloys. The corrosion resistance two Ni alloys in 1 M NaCl solution evaluated with electrochemical cyclic polarization measurement. synchrotron XPS measurement provided detailed information about chemical states alloying elements film, showing that consists an inner oxide layer outer hydroxide layer. data...

Passivation behavior of a N- and V-containing martensite stainless steel was studied by synchrotron-based near ambient-pressure X-ray photoelectron spectroscopy, electrochemical analyses, thermodynamic calculation. The passive film consists Cr3+, Fe(2, 3)+, V(2, 3, 4)+ oxides as inner layer, Cr3+ Fe3+ hydroxides outer layer. Austenitization at 1080 oC (rather than 1010 oC) anodic polarization facilitate transformation CrN to Cr2O3 leading further enrichment oxide in the film. Whereas higher...

Abstract Corrosion results in large costs and environmental impact but can be controlled by thin oxide films that passivate the metal surfaces hinder further oxidation or dissolution an aqueous environment. The structure, chemistry, thickness of these play a significant role determining their anti-corrosion properties early-stage dynamics affect developed oxide. Here, we use situ X-ray Photoelectron Spectroscopy (XPS) to study Ni-Cr-Mo alloy at room temperature up 400 °C. Cr Mo begin oxidize...

The anodic corrosion behavior of 50 Å thick single-crystalline IrO2(110) films supported on slightly bulk-reduced TiO2(110) single crystals is studied during acidic water splitting by a unique combination operando techniques, namely, synchrotron-based high-energy X-ray reflectivity (XRR) and surface diffraction (SXRD) together with highly sensitive inductively coupled plasma mass spectrometry (ICP-MS). Corrosion-induced structural morphological changes the model electrode can be followed...

• In-situ ambient pressure XPS methodology for electrochemical oxide growth presented. Quantitative analysis data further developed. Enrichment of MoO 3 observed at higher applied potentials. Ambient Pressure X-ray Photoelectron Spectroscopy combined with an setup is used to study, in situ, the on industrial Ni-Cr-Mo alloy. The native film was characterized vacuum and water vapor 17 mbar, found be 11.4 Å thick rich Cr 3+ . In 0.1M NaCl electrolyte, anodic potentials up 700 mV vs. Ag/AgCl...

We have developed an electrochemical cell for in situ 2-Dimensional Surface Optical Reflectance (2D-SOR) studies during anodization and cyclic voltammetry. The 2D-SOR signal was recorded from electrodes made of polycrystalline Al, Au(111), Pt(100) single crystals. changes can be followed at a video rate acquisition frequency 200 Hz demonstrate strong contrast between oxidizing reducing conditions. Good correlation the conditions or voltammetry current is also observed. power this approach...

We have developed a microscope with spatial resolution of 5 μm, which can be used to image the two-dimensional surface optical reflectance (2D-SOR) polycrystalline samples in operando conditions. Within field science, tools that give information about structure or chemistry sample under realistic experimental conditions proven very valuable understand intrinsic reaction mechanisms thermal catalysis, electrocatalysis, and corrosion science. To study heterogeneous surfaces situ, technique must...

We report the evolution of metastable precursor structures during hydrogen infusion in near-surface region a super duplex stainless steel. Grazing-incidence x-ray diffraction was employed to monitor, operando, lattice degradation austenite and ferrite phases. Electrochemical charging resulted splitting peaks phase, suggesting structure. This may be explained by formation quasi-hydrides, which convert back into parent structure effusion. The showed less deformation than no phase transformation.

The catalytic oxidation of HCl by molecular oxygen (Deacon process) over ceria allows the recovery chlorine from omnipresent waste produced in various industrial processes. In previous density functional theory (DFT) model-calculations Amrute et al. [ J. Catal. 2012, 286, 287−297.], it was proposed that most critical reaction step this process is displacement tightly bound at a vacant position on CeO2(111) surface (Clvac) toward less strongly cerium on-top (Cltop) position. This highly...

Many surface science experiments within heterogeneous catalysis are now conducted in realistic conditions at higher pressures. At these pressures, localized gas will form throughout the reactor. Understanding and their interaction with catalyst relevant time scales spatial resolution is important. To address this issue, we use a combination of techniques that can resolve composition enough temporal to show even very rapid gas–surface interactions. Planar laser-induced fluorescence used...

We investigated the structural evolution of electrochemically fabricated Pd nanowiresin situby means grazing-incidence transmission small- and wide-angle x-ray scattering (GTSAXS GTWAXS), fluorescence (XRF) two-dimensional surface optical reflectance (2D-SOR). This shows how electrodeposition hydrogen reaction (HER) compete interact during electrodepositon. During bottom-up growth nanowires, we show thatβ-phase hydride is formed. Suspending then leads to a phase transition fromβ-phase...

Abstract The reformation and characterisation of the passive film formed on ultra-thin 316 L after hydrogen charging is investigated by combining EBSD, TMDS, XRD, Synchrotron-based XPS, electrochemical experiments. results show that foil reforms a 12 h release in NaCl solution. reformed half thickness as-received dominated Cr oxides/hydroxides. lattice extension caused residual accelerates migration to form 2 O 3 ; while diffusible occupies cation vacancies high defect density for within h.

We have combined high-energy surface X-ray diffraction (HESXRD) with 2D optical reflectance (2D-SOR) to perform in situ electrochemical measurements of a Au(111) electrode 0.1 M HClO 4 electrolyte. show that electrochemically induced changes during cyclic voltammetry can be simultaneously observed 2D-SOR and HESXRD. discuss how small one atom high 1x1 islands, accommodating excess atoms after the lifting reconstruction, lead discrepancies between two techniques. The use HESXRD allows us...

Effect of tempering temperature on the composition passive film a martensitic tool alloy was studied by synchrotron-based hard/soft X-ray photoelectron spectroscopy and electrochemical analyses. The contents Cr Mo in are affected precipitation carbides. Increase from 200 to 525°C leads enhanced formation Cr/Mo-rich carbides depletion. Tempering at results content < 11 at.% underlying metallic layer Cr-deficient defective film, thus loss passivity for corrosive conditions.

Traditional methods to study electrochemical (EC) processes, although successful, are based on current/voltage measurements, providing information about performances rather than offering a direct observation of chemical and structural changes occurring at the electrode surface. These processes localized electrode-electrolyte interface, structure which is main determinant their behavior, but most surface sensitive experimental techniques limited ex situ conditions, owing need for an...

Grazing-incidence x-ray diffraction was employed to measure, operando, during electrochemical hydrogen charging, the lattice strain development of near-surface in super duplex stainless steel under applied tensile load. Hydrogen absorption led formation strains both austenite (γ) and ferrite (δ) phases perpendicular loading axis, whereas compressive were formed phase parallel direction, despite acting The earliest stages degradation are discussed light understanding embrittlement.

A method for the electrochemical synthesis of palladium nanowires, using porous alumina templates with diameters 25 nm and 40 nm, is presented. Through an barrier layer thinning step, pulsed electrodeposition can take place directly into anodized aluminum; without need extra removal, pore opening, metal contact coating steps. digital oscilloscope used to record integrate current, allowing efficiency be calculated. We discuss how a large “off period” allows replenishment depleted diffusion...

The electrochemical growth of Au nanowires in a template nanoporous anodic aluminum oxide was investigated situ by means grazing-incidence transmission small- and wide-angle x-ray scattering (GTSAXS GTWAXS), fluorescence (XRF), two-dimensional surface optical reflectance. XRF the overall intensity GTWAXS patterns as function time were used to monitor progress electrodeposition. Furthermore, we extracted powder diffraction direction confinement follow evolution direction-dependent strain....

The CO2 corrosion-induced scale developed in the surface region of low-grade carbon steel is thoroughly investigated to understand corrosion mechanisms involved during exposure CO2-saturated aqueous environments. In this work, addition electron microscopy and lab-source X-ray diffraction (XRD) methods, ex-situ depth-resolved phase identification scales on with different initial microstructures performed using synchrotron grazing incidence XRD at angles. mechanism discussed considering...