Localized corrosion mechanism of 2×××-series Al alloy containing S(Al2CuMg) and θ′(Al2Cu) precipitates in 4.0% NaCl solution at pH 6.1

The influences of co-deposited Ti particles on corrosion behavior of electrodeposited Ni-Ti coatings were investigated. The co-deposited Ti particles caused the refined crystallite size and random-oriented texture of Ni-Ti coating. In 3.5 wt% sodium chloride (NaCl) solution, the buried Ti particles in Ni matrix blocked the corrosion path and rapid intercrystalline corrosion. The inert TiO2 could form on the exposed Ti particles and hinder localized corrosion. In 10 wt% sodium hydroxide (NaOH) solution, Ni matrix crystallites, refined by co-deposited Ti particles, contributed to formation of the passive Ni(OH)2 film. The corrosion current of Ni-Ti coating decreased by about one order of magnitude in both solutions with respect to pure Ni coating, demonstrating the co-deposited Ti particles greatly improved the corrosion resistance of Ni-Ti composite coatings. Finally, a corrosion mechanism was built to explain the co-deposited Ti particles improved corrosion resistance of the Ni-Ti composite coatings.

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Use of Amperometric and Potentiometric Probes in Scanning Electrochemical Microscopy for the Spatially-Resolved Monitoring of Severe Localized Corrosion Sites on Aluminum Alloy 2098-T351

Sensors ◽

10.3390/s21041132 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1132 ◽

Cited By ~ 1

Author(s):

Rejane M. P. da Silva ◽

Javier Izquierdo ◽

Mariana X. Milagre ◽

Abenchara M. Betancor-Abreu ◽

Isolda Costa ◽

...

Keyword(s):

Scanning Electrochemical Microscopy ◽

Oxygen Depletion ◽

Localized Corrosion ◽

Alloy Surface ◽

Al Alloy ◽

Spatially Resolved ◽

Lower Oxygen ◽

Local Ph ◽

Electrochemical Microscopy

Amperometric and potentiometric probes were employed for the detection and characterization of reactive sites on the 2098-T351 Al-alloy (AA2098-T351) using scanning electrochemical microscopy (SECM). Firstly, the probe of concept was performed on a model Mg-Al galvanic pair system using SECM in the amperometric and potentiometric operation modes, in order to address the responsiveness of the probes for the characterization of this galvanic pair system. Next, these sensing probes were employed to characterize the 2098-T351 alloy surface immersed in a saline aqueous solution at ambient temperature. The distribution of reactive sites and the local pH changes associated with severe localized corrosion (SLC) on the alloy surface were imaged and subsequently studied. Higher hydrogen evolution, lower oxygen depletion and acidification occurred at the SLC sites developed on the 2098-T351 Al-alloy.

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Radial Spreading of Localized Corrosion-Induced Selective Leaching on α-Brass in Dilute NaCl Solution

CORROSION ◽

10.5006/0611 ◽

2013 ◽

Vol 69 (5) ◽

pp. 468-476 ◽

Cited By ~ 5

Author(s):

Mattias Forslund ◽

Christofer Leygraf ◽

Changjian Lin ◽

Jinshan Pan

Keyword(s):

Localized Corrosion ◽

Selective Leaching ◽

Nacl Solution ◽

Radial Spreading

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Assessment of nickel titanium and beta titanium corrosion resistance behavior in fluoride and chloride environments

The Angle Orthodontist ◽

10.2319/091712-740.1 ◽

2013 ◽

Vol 83 (5) ◽

pp. 864-869 ◽

Cited By ~ 8

Author(s):

Elisa J. Kassab ◽

José Ponciano Gomes

Keyword(s):

Corrosion Resistance ◽

Corrosion Behavior ◽

Electrochemical Impedance ◽

Fluoride Concentration ◽

Nickel Titanium ◽

Localized Corrosion ◽

General Corrosion ◽

Nacl Solution ◽

Galvanic Coupling ◽

Beta Titanium

ABSTRACT Objective: To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride. Materials and Methods: NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy. Results: Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium. Conclusions: There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.

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Nanoscale corrosion investigation of surface nanocrystallized 7150 Al alloy in 3.5 wt% NaCl solution by using FIB-TEM techniques

Corrosion Science ◽

10.1016/j.corsci.2021.110021 ◽

2021 ◽

pp. 110021

Author(s):

Qingqing Sun ◽

Fahe Cao ◽

Shuai Wang

Keyword(s):

Al Alloy ◽

Nacl Solution ◽

Corrosion Investigation

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Friction Stir Welding with Low-Medium-High Tool Travel Speed of 0.95 Mg-Al-Alloy and Pure Copper: Electrochemical and Surface Studies

10.20944/preprints201812.0039.v1 ◽

2018 ◽

Author(s):

Neetesh Soni ◽

Ambrish Singh

Keyword(s):

Friction Stir Welding ◽

Process Parameters ◽

Pure Copper ◽

Travel Speed ◽

Localized Corrosion ◽

Al Alloy ◽

Kelvin Probe ◽

Friction Stir ◽

Surface Optical ◽

Joining Process

The aim of this work is to assess the influence of Friction Stir Welding (FSW), process parameters, optimized tool traveling speed, and corrosion resistance of the 0.95 Mg-Al-alloy and pure copper weldment. Samples of aluminum-copper with and without deformation were characterized to investigate the metallurgical effects created during the welding deformation process. Effect of process parameters on microstructure and corrosion rate have been investigated for all the samples. All the electrochemical and polarization tests were done in 3.5 wt.% NaCl solution. Scanning Kelvin Probe (SKP) was done to detect the localized corrosion on the surface. Optical micrography observation indicated that the primary α-Al phase, which was formed during solidification can effectively limit the growth of Cu9Al4 phase. Finer acicular α-Al precipitates were observed in CuAl matrix during joining process that tends to coarser with the increase in tools travel speed. The electrochemical and polarization results showed that among all the tool travelling speed the specimen joined at tool travelling speed of 40 mm/min shows the best non-corrosive property.

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