Sudden Onset of Pitting Corrosion on Stainless Steel as a Critical Phenomenon

Punckt, Christian; Bölscher, M; Rotermund, Harm Hinrich; Mikhailov, Alexander S.; Organ, Levent; Budiansky, Noah; Scully, John R.; Hudson, John L.

doi:10.1126/science.1101358

Cited by 272 publications

(146 citation statements)

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“…According to the decrease of the O 1s intensity with exposure, the initial removal rate is low, accelerates around 0.5 L, stops at 1 L and proceeds to the final composition FeO 0.75 at 2-3 L. Between 0 and 1 L, this behavior is characteristic for an autocatalytic process with saturation after 1L. The kinetics is similar to that of oxide reduction in electrochemical pitting corrosion of stainless steel which recently was identified as due to an autocatalytically accelerated growth in the number of active pits [33].…”

Section: H At On Feo(111) -Discussionsupporting

confidence: 48%

“…The observed partial reduction of a thin FeO film grown on a Pt(111) substrate by exposure to gaseous atomic hydrogen H at represents a type of autocatalytic surface reactions which so far has only been observed in electrochemical pitting corrosion of oxide films [33]. A mechanism is proposed according to which reduction starts at oxygen vacancies.…”

Section: Discussionmentioning

confidence: 98%

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Autocatalytic partial reduction of FeO(111) and Fe3O4(111) films by atomic hydrogen

Huang

Ranke

2006

Surface Science

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The interaction of atomic hydrogen with thin epitaxial FeO(111) and Fe3O4(111) films was studied by TDS, XPS and LEED. On the thin, one Fe-O bilayer thick FeO film, partial reduction occurs in two steps during exposure. It ends after removal of ¼ monolayer (ML) of oxygen with a 2´2 pattern appearing in LEED. This FeO0.75 film is passive against further reduction. The first reduction step saturates after removal of ~0.2 ML and shows autocatalytic kinetics with the oxygen vacancies formed during reduction causing acceleration. The second step is also autocatalytic and is related with reduction to the final composition and an improvement of the 2´2 order. A structure model explaining the two-step reduction is proposed. On the thick Fe3O4 film, irregular desorption bursts of H2O and H2 were observed during exposure. Their occurrence appears to depend on the film quality and thus on surface order. Because of the healing of reduction-induced oxygen vacancies by exchange of oxygen or iron with the bulk, a change of the surface composition was not visible. The existence of partially reduced oxide phases resistant even to atomic hydrogen is relevant to the mechanism of dehydrogenation reactions using iron oxides as catalysts.Key words: Low energy electron diffraction, X-ray photoelectron spectroscopy, temperature programmed desorption, catalysis, surface chemical reaction, hydrogen atom, iron oxide IntroductionIron oxides, widespread in nature, are of interest to many scientific disciplines from geology to biology [1]. The reduction of iron oxides is inevitable in many processes, such as metallurgy, corrosion, and heterogeneous catalysis. It was long found that the very rapid dissolution of the passive iron oxides film on iron involves a reductive mechanism [2]. The surface reduction, together with coke formation, is responsible for the deactivation of the iron oxide-based catalyst for the dehydrogenation of ethylbenzene to styrene [3,4]. Because of their relevance for corrosion processes, the reduction of iron oxides in solution has been extensively studied and a clear understanding of the mechanism and kinetics is acquired [5]. However, fundamental understanding of of iron oxide reduction by gas phase hydrogen is poor.Most fundamental understanding of the gas-solid interactions comes from surface science studies of relevant model systems under ultra-high-vacuum (UHV) conditions. Very little is known about the interaction of hydrogen with well-characterized single-crystal iron oxides. The nearly stoichiometric, well ordered a-Fe 2 O 3 (0001) surface is inert towards molecular hydrogen at room temperature and interaction occurs only at defects [6]. Thus it is difficult to approach the reduction of iron oxides by employing molecular hydrogen. The reason is, of course, the high dissociation energy of H 2 (432 kJ/mol). Atomically adsorbed hydrogen, OH groups or protons are formed in catalytic dehydrogenation reactions or during electrochemical reduction. Therefore it makes sense to study the interaction of surfaces...

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Section: H At On Feo(111) -Discussionsupporting

confidence: 48%

Section: Discussionmentioning

confidence: 98%

Autocatalytic partial reduction of FeO(111) and Fe3O4(111) films by atomic hydrogen

Huang

Ranke

2006

Surface Science

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“…The growth of urban sprawl is another near 2D growth phenomenon for which detailed land use records and satellite imaging provide information about the front structure and dynamics (42). From a material science standpoint, it would be interesting to pursue studies of frontal polymerization (43), the corrosion of metallic films (44), and polymer dissolution (45), fronts in thin films to determine whether our results apply broadly to these phenomena as well. The general finding that fluctuation effects tend to make these fronts increasingly incoherent in time (diffuse) can be expected to have a large impact on the interaction of these frontal patterns under conditions where species (or different types of ordering) are competing for supremacy.…”

Section: Implications Of Observationsmentioning

confidence: 99%

Propagating waves of self-assembly in organosilane monolayers

Douglas

Efimenko

Fischer

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Wavefronts associated with reaction-diffusion and self-assembly processes are ubiquitous in the natural world. For example, propagating fronts arise in crystallization and diverse other thermodynamic ordering processes, in polymerization fronts involved in cell movement and division, as well as in the competitive social interactions and population dynamics of animals at much larger scales. Although it is often claimed that self-sustaining or autocatalytic front propagation is well described by mean-field ''reaction-diffusion'' or ''phase field'' ordering models, it has recently become appreciated from simulations and theoretical arguments that fluctuation effects in lower spatial dimensions can lead to appreciable deviations from the classical mean-field theory (MFT) of this type of front propagation. The present work explores these fluctuation effects in a real physical system. In particular, we consider a high-resolution near-edge x-ray absorption fine structure spectroscopy (NEXAFS) study of the spontaneous frontal self-assembly of organosilane (OS) molecules into self-assembled monolayer (SAM) surface-energy gradients on oxidized silicon wafers. We find that these layers organize from the wafer edge as propagating wavefronts having well defined velocities. In accordance with two-dimensional simulations of this type of front propagation that take fluctuation effects into account, we find that the interfacial widths w(t) of these SAM self-assembly fronts exhibit a power-law broadening in time, w(t) Ϸ t ␤ , rather than the constant width predicted by MFT. Moreover, the observed exponent values accord rather well with previous simulation and theoretical estimates. These observations have significant implications for diverse types of ordering fronts that occur under confinement conditions in biological or materials-processing contexts.fluctuation-induced interfacial broadening ͉ frontal self-assembly ͉ mean-field Fisher-Kolmogorov equation ͉ reaction-diffusion fronts ͉ self-assembled monolayers I n the early 1990s, Chaudhury and Whitesides developed an extremely facile method of creating surface energy gradients using self-assembled monolayers (SAMs) (1). Rather than using a solution as a carrier for adsorption or a rubber stamp for direct deposition of SAM molecules, these researchers simply placed a volatile fluid of organosilane (OS) molecules at the edge of a silica-covered substrate and enclosed the entire system in a container to avoid convection effects (Fig. 1). The symmetry-breaking perturbation associated with placing the source of diffusing material to the side of the wafer imparts a direction to the self-assembly of the SAM layer and leads to the spontaneous formation of a concentration gradient of OS molecules on the substrate. This gradient may be fixed into position at any point in its development by simply removing the wafer from OS exposure (2). These kinetically ''frozen'' SAM patterns are then ready for further measurements in which surface energy gradients are required.Although this method of ...

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“…Impurities such as inclusions, precipitates and second phases can present in metals and alloys and influence the mechanical properties at high and/or low service temperatures [1,2]. These particles also affect the electrical properties of metals and alloys, e.g.…”

Section: Introductionmentioning

confidence: 99%

Oriented sulphides induced by electric current in medium carbon steel

Zhang

Qin

2015

Philosophical Magazine Letters

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Oriented sulphides parallel to the electric current direction have been experimentally observed when a pulsed electric current is passed through medium carbon steels with MnS inclusions. Two different configurations of sulphides occur after the application of the electric current: namely, oriented elongated ellipsoidal particles and oriented chain-like particles composed of two or three small spherical sulphides. Theoretical analysis indicates that this phenomenon is associated with minimisation of the electrical resistance of the material.

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Sudden Onset of Pitting Corrosion on Stainless Steel as a Critical Phenomenon

Cited by 272 publications

References 20 publications

Autocatalytic partial reduction of FeO(111) and Fe3O4(111) films by atomic hydrogen

Autocatalytic partial reduction of FeO(111) and Fe3O4(111) films by atomic hydrogen

Propagating waves of self-assembly in organosilane monolayers

Oriented sulphides induced by electric current in medium carbon steel

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