scholarly journals Application of Kelvin Probe Force Microscopy (KFM) to Evidence Localized Corrosion of Over-Aged Aeronautical 2024 Aluminum Alloy

2013 ◽  
Vol 550 ◽  
pp. 127-134
Author(s):  
Nicoleta Radutoiu ◽  
Joël Alexis ◽  
Loïc Lacroix ◽  
Marioara Abrudeanu ◽  
Jacques Alain Petit
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Corrosion Damage ◽  
Localized Corrosion ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Intermetallic Particles ◽  
2024 Alloy ◽  
The Matrix

The 2xxx serie aluminum alloys are characterized by good mechanical performances and low density, however they are susceptible to different forms of localized corrosion: pitting corrosion, intergranular corrosion and stress corrosion cracking. The 2024-T351 aluminum alloy is used in the aircraft industry for numerous applications such as fuselage and door skin. Corrosion damage of the material is also very detrimental for the structural integrity of the aircraft. The presence of coarse intermetallic particles, with a heterogeneous size distribution was found to be responsible for the 2024 susceptibility to localized corrosion. These particles are generally the cause of initiation sites. Presence of micro-defects in the oxide film upon coarse intermetallic particles and the galvanic coupling with the matrix contribute to the development of pitting corrosion. The over-ageing treatment (T7) is supposed to stabilize the microstructure and the mechanical properties to improve the corrosion resistance. The 2024 alloy microstructure after the T7 heat treatment remains very complex. The 2024 alloy corrosion behavior was studied in the over-ageing state for three different temperatures (150, 175 and 190 °C). During the corrosion tests in chloride-containing environment, the behavior of coarse intermetallic particles was found to be different. Thus, the 2024 samples suffer a gradual attack upon S-Al2CuMg particles and finally Al (Cu,Mn,Fe,Si) particles. The corrosion damage was studied by Atomic Force Microscopy (AFM) and Kelvin probe Force Microscopy (KFM). This technique allows simultaneous topographical and electric potential mapping to be obtained. This latest potential was shown to be correlated to the corrosion potential of the 2024 alloy. This study focuses on the variation of the KFM potential of the coarse intermetallic particles and the matrix for the over-ageing conditions (T7). Observations using optical microscope and AFM were also performed to obtain the corrosion rate for each condition. The corrosion rate was correlated to the chemical composition variation of the particles obtained by scanning electron microscope observations and EDS analyses.

scholarly journals Influence of Aging on Corrosion Behaviour of the 6061 Cast Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1821
Author(s):  
Ting He ◽  
Wei Shi ◽  
Song Xiang ◽  
Chaowen Huang ◽  
Ronald G. Ballinger
Keyword(s):  
Aluminium Alloy ◽  
Laser Scanning ◽  
Corrosion Behaviour ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
The Matrix ◽  
6061 Aluminium Alloy

The influence of AlFeSi and Mg2Si phases on corrosion behaviour of the cast 6061 aluminium alloy was investigated. Scanning Kelvin probe force microscopy (SKPFM), electron probe microanalysis (EPMA), and in situ observations by confocal laser scanning microscopy (CLSM) were used. It was found that Mg2Si phases were anodic relative to the matrix and dissolved preferentially without significantly affecting corrosion propagation. The AlFeSi phases’ influence on 6061 aluminium alloy local corrosion was greater than that of the Mg2Si phases. The corroded region width reached five times that of the AlFeSi phase, and the accelerating effect was terminated as the AlFeSi dissolved.

The Combined Effect of Chemical and Structural Factors on Pitting Corrosion Induced by MnS-(Cr, Mn, Al)O Duplex Inclusions

CORROSION ◽  
10.5006/2581 ◽  
2017 ◽  
Vol 74 (3) ◽  
pp. 312-325 ◽  
Author(s):  
Cheng Man ◽  
Chaofang Dong ◽  
Kui Xiao ◽  
Qiang Yu ◽  
Xiaogang Li
Keyword(s):  
Pitting Corrosion ◽  
Selective Dissolution ◽  
Dissolution Mechanism ◽  
Structural Factors ◽  
Metal Interface ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Individual

In situ atomic force microscopy, scanning Kelvin probe force microscopy, and potential pulse technology were used to study the pitting behavior induced by inclusions in AM355 martensitic stainless steel. The MnS-(Cr, Mn, Al)O duplex inclusion exhibited the highest sensitivity to the pitting corrosion with respect to the individual MnS and (Cr, Mn, Al)O inclusions. When exposed to a solution containing Cl−, the selective dissolution occurred on the sulfide segment of the duplex inclusion, leading to trenching along the oxide part. The dissolution mechanism of MnS segment in the duplex inclusion is similar to the individual MnS inclusion. The Cr depletion in the boundary layer at the inclusion/metal interface promoted the transition from metastable to stable pitting corrosion in the duplex inclusion.

scholarly journals The role of chromium content in the long-term atmospheric corrosion process

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Baozhuang Sun ◽  
Xiaomei Zuo ◽  
Xuequn Cheng ◽  
Xiaogang Li
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Atmospheric Corrosion ◽  
X Ray Diffraction ◽  
Kelvin Probe ◽  
Electrochemical Tests ◽  
Force Microscopy ◽  
Cr Content ◽  
Alloy Steels ◽  
Bare Steel

AbstractThe corrosion of alloy steels with different amounts of Cr was studied using electrochemical tests, wet–dry cycle corrosion, X-ray diffraction, and Kelvin probe force microscopy. The results show that the content of Cr is positively correlated with the corrosion resistance of bare steel, but the corrosion resistance of atmospheric corrosion does not show the same pattern. The atmospheric corrosion resistance of Cr-containing steel exhibits three different stages with the change of Cr element content. When the Cr content is in the range of 1–4%, the corrosion rate is high and does not change within the Cr content. As the Cr content was further increased from 4 to 7%, the corrosion rate exhibited a linear decrease and then drops rapidly when the Cr content reaches 8%. These three different corrosion rate stages are related to the influence of Cr content on Fe3O4 content in the rust layer.

Use of Scanning Kelvin Probe Force Microscopy to Investigate the Effects of Surface Preparation on Intermetallic Particles in AA7xxx Aluminum Alloys

2019 ◽  
Vol 41 (25) ◽  
pp. 107-120 ◽  
Author(s):  
Weilong Zhang ◽  
Xiaomei Yu ◽  
Michael Kryzman ◽  
Thomas J. Garosshen ◽  
Marcin Piech ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Surface Preparation ◽  
Kelvin Probe Force Microscopy ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Scanning Kelvin Probe ◽  
Intermetallic Particles

Study of the Degradation Behaviour of Biomaterial Mg-4.0Zn-2.0Sr Alloy in SBF

2015 ◽  
Vol 1095 ◽  
pp. 309-313 ◽  
Author(s):  
Tong Cui ◽  
Ren Guo Guan ◽  
Hai Ming Qin ◽  
Fu Lin Song
Keyword(s):  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Biological Properties ◽  
Alloy Sheet ◽  
Localized Corrosion ◽  
Cyclic Process ◽  
Degradation Behaviour ◽  
Corrosion Resistance Property ◽  
Corrosion Pitting ◽  
Average Corrosion Rate

In v itro degradation behaviour and biological properties of Mg-4.0Zn-2.0Sr alloy sheet had been studied. The results indicate that a novel biodegradable Mg-4.0Zn-2.0Sr (wt. %) alloy sheet was successfully produced using a series of metallurgical processes. The corrosion of Mg-4.0Zn-2.0Sr (wt. %) alloy sheet immersed in SBF occurred as a cyclic process: pitting corrosion →extending of pitting corrosion along grain boundary→ localized corrosion → pitting corrosion again at the new exposed surfaces and the corrosion products were found that contain HA, CaCO3 and MgOH. The change of corrosion rate of Mg-4.0Zn-2.0Sr alloy sheets immersed in SBF is unstable until the 17th day and the average corrosion rate of the alloy sheets was 1.244 g/(m2 • h) after 17 days immersing, which is slightly higher than that of Mg-4.0Zn-1.0Sr alloy sheet 1.163 g/(m2 • h). The corrosion resistance property in SBF of Mg-4.0Zn-2.0Sr alloy is slightly lower than that of Mg-4.0Zn-1.0Sr alloy, which is proved by electrochemical measurements.

scholarly journals Research on Corrosion Damage Evolution of Aluminum Alloy for Aviation

2020 ◽  
Vol 10 (20) ◽  
pp. 7184
Author(s):  
Zhigang Gao ◽  
Yuting He ◽  
Sheng Zhang ◽  
Tianyu Zhang ◽  
Fei Yang
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Rate ◽  
Early Stage ◽  
Three Dimensional ◽  
Gumbel Distribution ◽  
Corrosion Damage ◽  
Environmental Data ◽  
Evolution Law ◽  
Immersion Corrosion ◽  
Corrosion Pits

Based on the real annual average value of atmospheric environmental data in the Wanning area of Hainan Province in China by selecting 7075 ultra-high-strength aluminum alloy specimens for aviation, a new corrosion solution was designed and the traditional alternate immersion corrosion method of using the alternate immersion corrosion test box was improved to simulate the environment of the internal structure of the aircraft. On this basis, two kinds of corrosion damage parameters, the depth of corrosion pits and corrosion rate, were quickly and accurately obtained by the three-dimensional profile of the specimen and binarization images’ method. The optimal linear regression equation combination of pitting depth and corrosion rate was established, and the dynamic evolution equation of the depth of corrosion pits and corrosion rate was obtained. The results showed that: The depth of corrosion pits in the early stage of corrosion (8 h and 24 h) obeyed the Gumbel distribution and Weibull distribution, respectively, and the later stage (48 h, 72 h, 96 h, and 120 h) conformed to the normal distribution; the depth of corrosion pits’ evolution law was in the form of double straight lines and the corrosion rate evolution law was in the power function form (y = a × xb); and the depth of corrosion pits changed rapidly in the early stage and gradually slowed down in the later stage, while the corrosion rate was just the opposite.

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