Insights into Grain Structures and Their Reactivity on Grade-2 Ti Alloy Surfaces by Scanning Electrochemical Microscopy

Zhu, Renkang; Nowierski, Catherine; Ding, Zhifeng; Noël, and James J.; Shoesmith, David W.

doi:10.1021/cm070023d

Cited by 51 publications

(63 citation statements)

References 54 publications

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“…The availability of active electronic current pathways across the TiO 2 oxide, which is normally considered an insulator at potentials positive of ∼−0.6 V SCE , has been demonstrated at potentials more positive than ∼−0.6 V SCE by Zhu et al, 17,18 who used scanning electrochemical microscopy to observe the activation of localized electronically conducting sites at which cathodic current could be passed at potentials as mild as −0.04 V SCE . The number and activity of such sites increased as the potential was made more negative.…”

Section: Discussionmentioning

confidence: 99%

Hydrogen Absorption into Titanium under Cathodic Polarization: An In-Situ Neutron Reflectometry and EIS Study

Vezvaie¹,

Noël

Tun³

et al. 2013

J. Electrochem. Soc.

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Hydrogen (deuterium) absorption into sputter-coated titanium (Ti) film electrodes during cathodic polarization in heavy water (D 2 O) was monitored using in-situ neutron reflectometry (NR) and electrochemical impedance spectroscopy (EIS). The scattering length density (SLD) of Ti metal increased with increasing cathodic polarization, due to the penetration of deuterium through the surface oxide and into the underlying metal. The rate of D absorption estimated from the NR data showed a pattern with four distinctive regions separated by potential boundaries between −0.35 and −0.4 V SCE and around ∼−0.6 V SCE . EIS results support division of the behavior into these potential ranges. Hydrogen absorption by Ti was observed at potentials <∼−0.35 V SCE , where the capacitance and resistance of the TiO 2 layer dramatically changed. At this point, the D content of the film quickly achieved a level of ∼900 ppm by weight (atom ratio D:Ti ∼ 0.04). Decreased absorption kinetics were observed over the potential region from ∼−0.40 V SCE to −0.6 V SCE , indicating that D absorption was controlled either by a diffusion process through the TiO 2 layer or by the formation of blocking hydrides at the Ti/TiO 2 interface, at the base of the defective locations in the oxide through which the hydrogen was entering. Significant increases in the current density and SLD of the Ti film at potentials more negative than −0.6 V SCE were assigned to widespread hydrogen absorption and TiH x growth within the metal. These observations are consistent with hydrogen ingress through the oxide film, probably via weak points containing electronic defects and disorder, such as grain boundaries and triple points, at potentials as mild as ∼−0.4 V SCE , and with hydrogen penetration through continuous, intact oxide via the previously published redox transformation mechanism, at potentials more negative than −0.6 V SCE . Titanium corrosion processes are often accompanied by hydrogen production. For example, 80% or more of the crevice corrosion process on Ti is driven by the reduction of protons inside the crevice:This leads to the absorption of atomic hydrogen, and can result in extensive hydride formation. 1,2 Cathodic polarization and galvanic coupling with active metals can also cause hydrogen evolution on the Ti surface and hydrogen penetration into the bulk metal. Since hydrogen absorption into Ti structures can lead to their failure by brittle cracking, once the hydrogen concentration achieves a critical level, 3 safe operation of such structures requires a detailed knowledge of the mechanism of hydrogen entry into Ti so that exposure conditions that put the structure at risk of hydrogen-induced cracking can be avoided. A number of studies have been done on the physicochemical properties of Ti/H systems, as well as on hydrogen-induced cracking of Ti.3,4 Here we explore the role of the electrochemical potential in determining whether adsorbed hydrogen atoms generated by water reduction can penetrate the native oxide on Ti.The surface oxide layer play...

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Section: Discussionmentioning

confidence: 99%

Hydrogen Absorption into Titanium under Cathodic Polarization: An In-Situ Neutron Reflectometry and EIS Study

Vezvaie¹,

Noël

Tun³

et al. 2013

J. Electrochem. Soc.

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“…The real gap distance between the tip and the specimen was estimated by comparing experimental PACs with simulated/theoretical PACs, as shown in the previous work. 14,[19][20][21][22] The UME gap distance was maintained at constant and scanned above the specimen to obtain the SECM images of the X80 surface. The passive film exhibits semiconductor properties, and it was considered to be an inactive film.…”

Section: Electrochemical Methodsmentioning

confidence: 99%

Hydrogen-enhanced Surface Reactivity of X80 Pipeline Steel observed by Scanning Electrochemical Microscopy

Xia

Zhu

et al. 2016

Electrochemistry

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Effect of hydrogen on the surface reactivity of X80 pipeline steel was studied by scanning electrochemical microscopy (SECM), electrochemical impedance spectroscopy (EIS) and secondary ion mass spectroscopy (SIMS). Hydrogen can enhance the reactivity of passive film formed on X80 pipeline steel, reduce the corrosion resistance and thickness of this passive layer, which is due to an increase in hydroxide in the passive layer.

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“…It complements other scanning probe techniques such as the scanning reference electrode technique (SRET) [178,179], conductive scanning force microcopy (CSFM), electrochemical scanning tunneling microscopy (ECSTM), and scanning Kelvin probe techniques which are popular methods for the investigation of functional materials [180]. Basic experimental approaches include the imaging of the permeability of applied protective coatings [181][182][183][184][185][186][187][188][189][190][191][192][193], the imaging of regions with distinctly higher electron transfer rates which may be precursor sites for pitting corrosion [29,57,[194][195][196][197][198][199][200][201][202][203][204][205][206][207], the initiation of pitting corrosion by local generation of aggressive species at the UME [208,209] and the detection of active corrosion by collecting released species [55,58,60,104,[210][211][212][213][214]…”

Section: Localized Corrosionmentioning

confidence: 99%

“…Zhu et al investigated Ti-2 [207] and Ti-7 [241] alloy samples, containing Fe and Pd as alloying components, respectively, in the FB mode with hydroxymethylferrocene as redox mediator. Active spots with high positive feedback signals were observed and were associated with crystalline grain boundaries.…”

Section: Investigation Of Precursor Regionsmentioning

confidence: 99%

“…Furthermore, the influence of the substrate potential on the reactivity was investigated, and it was found that with more negative potentials, more active spots on the surface appeared. The authors ascribed this to the reduction of the oxide film (Ti(IV) to Ti(III)) and the onset of hydrogen adsorption in addition to the mediator regeneration [207]. Moreover, it was observed that active sites preferably start to appear at the triple points of grain boundaries and, with more negative potentials, propagate along the grain boundaries ( Figure 26) [241].…”

Section: Investigation Of Precursor Regionsmentioning

confidence: 99%

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Investigation of Localized Catalytic and Electrocatalytic Processes and Corrosion Reactions with Scanning Electrochemical Microscopy (SECM)

Pust¹,

Maier²,

Wittstock³

2008

Zeitschrift Für Physikalische Chemie

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Scanning Electrochemical Microscopy (SECM) . Catalytic Electrodes .Electrochemical Energy Conversion . Fuel Cells . Oxygen Reduction Reaction . CorrosionScanning electrochemical microscopy (SECM) has developed into a very versatile tool for the investigation of solid-liquid, liquid-liquid and liquid-gas interfaces. The arrangement of an ultramicroelectrode (UME) in close proximity to the interface under study allows the application of a large variety of different experimental schemes. The most important have been named feedback mode, generation-collection mode, redox competition mode and direct mode. Quantitative descriptions are available for the UME signal, depending on different sample properties and experimental variables. Therefore, SECM has been established as an indispensible tool in many areas of fundamental electrochemical research. Currently, it also spreads as an important new method to solve more applied problems, in which inhomogeneous current distributions are typically observed on different length scales. Prominent examples include devices for electrochemical energy conversion such as fuel cells and batteries as well as localized corrosion phenomena. However, the direct local investigation of such systems is often impossible. Instead, suitable reaction schemes, sample environments, model samples and even new operation modes have to be introduced in order to obtain results that are relevant to the practical application. This review outlines and compares the theoretical basis of the different SECM working modes and reviews the application in the area of electrochemical energy conversion and localized

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Insights into Grain Structures and Their Reactivity on Grade-2 Ti Alloy Surfaces by Scanning Electrochemical Microscopy

Cited by 51 publications

References 54 publications

Hydrogen Absorption into Titanium under Cathodic Polarization: An In-Situ Neutron Reflectometry and EIS Study

Hydrogen Absorption into Titanium under Cathodic Polarization: An In-Situ Neutron Reflectometry and EIS Study

Hydrogen-enhanced Surface Reactivity of X80 Pipeline Steel observed by Scanning Electrochemical Microscopy

Investigation of Localized Catalytic and Electrocatalytic Processes and Corrosion Reactions with Scanning Electrochemical Microscopy (SECM)

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