Monitoring local spatial distribution of Mg2+, pH and ionic currents

Lamaka, Sviatlana V.; Karavai, O.V.; Bastos, A.C.; Zheludkevich, Mikhail L.; Ferreira, M.G.S.

doi:10.1016/j.elecom.2007.12.003

Cited by 123 publications

(79 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Coated surfaces of Mg alloy AZ31 were reported to be analyzed by SVET at articial needle-defect zones. 44,51 SVET was also used for quantitative evaluation of "self-healing" effects of corrosion inhibitor when it is distributed in protective coating deposited on a metal surface. 52 Articial defects simulate the coating damage as might occur during its service-life.…”

Section: Protective Behavior Of Composite Coatingsmentioning

confidence: 99%

Active corrosion protection coating for a ZE41 magnesium alloy created by combining PEO and sol–gel techniques

et al. 2016

View full text Add to dashboard Cite

An active protective coating for ZE41 magnesium alloy was produced by sealing an anodic layer, loaded with 1,2,4-triazole, with a sol-gel film. An anodic oxide layer was formed using PEO in a silicate-fluoride alkaline solution. This thin (1.8 mm) porous PEO layer was impregnated with corrosion inhibitor 1,2,4-triazole and sealed with a silica-based sol-gel film modified with titanium oxide. For the first time it was demonstrated that this relatively thin PEO-based composite coating revealed high barrier properties and provided superior protection against corrosion attack during 1 month of continuous exposure to 3% NaCl. A scanning vibrating electrode technique showed a sharp decrease (100 times) of corrosion activity in micro defects formed in the 1,2,4-triazole doped composite coating, when compared to blank samples.

show abstract

Section: Protective Behavior Of Composite Coatingsmentioning

confidence: 99%

Active corrosion protection coating for a ZE41 magnesium alloy created by combining PEO and sol–gel techniques

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The downsizing of metal wires to dimensions close to the atomic scale has enabled scientists to study micro-or even nano-scale volumes and greatly improve the ability to characterize such confined systems, whether the wires are used in their pure state or coated with another material. [1][2][3][4][5] Microelectrodes are the key elements that made possible the development of relatively new electrochemical techniques, such as SECM (Scanning Electrochemical Microscopy) and SVET (Scanning Vibrating Electrode Technique), or imaging ones such as STM (Scanning Tunneling Microscopy). Through the use of microelectrode based techniques it has been possible to acknowledge fast reactions of the order of microseconds or less or even detect species in concentrations as low as a few ppb.…”

Section: Introductionmentioning

confidence: 99%

Novel electrochemical method of fast and reproducible fabrication of metallic nanoelectrodes

Silva

Zheludkevich

et al. 2014

Review of Scientific Instruments

View full text Add to dashboard Cite

A novel electrochemical wire etching method of fabrication of ultrasharp nanoelectrodes is reported. Tungsten wires can be sharpened to less than 10 nm tip radius in a reproducible manner in less than 1 min by using controllable hydrodynamic electrolyte flow combined with optimized electrochemical etching parameters. The method relies on the variations of the electric field at the surface of a metal wire, while the electrolyte solution is in motion, rather than on the ionic gradient generated in a static solution. © 2014 AIP Publishing LLC. [http://dx

show abstract

“…15,17 The potentiometric mode of SECM has also been extensively employed to characterize both pHs and Mg 2+ flux during corrosion of Mg alloys. 16,18,[33][34][35] The Mg 2+ is generated by anodic oxidation of the matrix phase (Equation 1) while the reduction of water occurs predominantly on the more noble alloy constituents (secondary phases) producing dissolved molecular H 2 and OH − species (Equation 2). Generation of OH − in the cathodic reaction leads to localized pH changes and the deposition of Mg(OH) 2 (Equation 3) on the alloy surface (K sp, Mg(OH) 2 = 5.61 × 10 −12 ).…”

mentioning

confidence: 99%

“…15,17 The potentiometric mode of SECM has also been extensively employed to characterize both pHs and Mg 2+ flux during corrosion of Mg alloys. 16,18,[33][34][35] …”

mentioning

confidence: 99%

“…Local scanning probe techniques such as several modes of scanning electrochemical microscopy (SECM), [13][14][15][16][17][18][19] scanning Kelvin probe force microscopy (SKPFM), [20][21][22] the scanning vibrating electrode technique (SVET) [23][24][25] and local electrochemical impedance spectroscopy (LEIS) 26 have been used to probe the heterogeneous surfaces of Mg alloys and to assess the electrochemical behavior of the different microstructural constituents responsible for microgalvanic corrosion. Among these techniques, SECM has the ability to quantify electrochemical fluxes in situ with high lateral resolution using a microelectrode (ME).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Local Hydrogen Fluxes Correlated to Microstructural Features of a Corroding Sand Cast AM50 Magnesium Alloy

Dauphin‐Ducharme

Asmussen

Tefashe

et al. 2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

Successful in situ spatiotemporal tracking of corrosion processes occurring at heterogeneous Mg alloy microstructures was achieved through tandem analyses involving electron and electrochemical microscopies. Through cross-correlation of scanning electron microscopy and scanning electrochemical microscopy images and subsequent analytical transmission electron microscopy, the morphology and chemical composition of microstructural components on the surface of a sand-cast AM50 Mg alloy were related to their respective local evolution of H 2 with micron scale resolution prior to, during and post corrosion. The results confirm that the preferential water reduction sites in the initial stages of corrosion are the Al 8 Mn 5 intermetallics while a β-Mg 17 Al 12 precipitate contaminated with Ni becomes cathodically active at a later stage of corrosion. This approach demonstrates the power of correlative approaches to probe and understand local electrochemical phenomena. Owing to their light weight, high strength-to-weight ratio, good castability and high damping capacity, Mg alloys are ideal candidates for automotive structural components.1-5 The compromise of formability, room temperature ductility and price represent major challenges in commercializing these materials. Importantly, Mg alloys also suffer from poor corrosion resistance in aqueous environments 6-8 and due to their positions in the electrochemical activity series, are highly susceptible to accelerated corrosion rates when in galvanic contact with a more noble material.9 At open circuit, the overall galvanic current is null due to a balance between the anodic and cathodic current densities, while on a microscopic scale, a difference in electrochemical potential is obtained. In Mg alloys, galvanic coupling between microstructural components of the alloy (commonly referred to as microgalvanic coupling) stems from an inherent electrochemical potential difference between the Mg matrix and its secondary phases, [10][11][12] and can be tracked using local scanning probe methods.Local scanning probe techniques such as several modes of scanning electrochemical microscopy (SECM), [13][14][15][16][17][18][19] scanning Kelvin probe force microscopy (SKPFM), 20-22 the scanning vibrating electrode technique (SVET) [23][24][25] and local electrochemical impedance spectroscopy (LEIS) 26 have been used to probe the heterogeneous surfaces of Mg alloys and to assess the electrochemical behavior of the different microstructural constituents responsible for microgalvanic corrosion. Among these techniques, SECM has the ability to quantify electrochemical fluxes in situ with high lateral resolution using a microelectrode (ME). 27 This technique has been successfully applied in corrosion research to provide in situ analyses of pitting corrosion at oxide films, [28][29][30] to assess lateral variations in corrosion kinetics, 31 and to detect defects within coated metal samples. 32The feedback mode of SECM has been employed to probe corroding AM60 15 and AZ31 17 Mg alloys. The incre...

show abstract

Monitoring local spatial distribution of Mg2+, pH and ionic currents

Cited by 123 publications

References 22 publications

Active corrosion protection coating for a ZE41 magnesium alloy created by combining PEO and sol–gel techniques

Active corrosion protection coating for a ZE41 magnesium alloy created by combining PEO and sol–gel techniques

Novel electrochemical method of fast and reproducible fabrication of metallic nanoelectrodes

Local Hydrogen Fluxes Correlated to Microstructural Features of a Corroding Sand Cast AM50 Magnesium Alloy

Contact Info

Product

Resources

About