Assessment of the corrosion protection of aluminium substrates by a Mg-rich primer: EIS, SVET and SECM study

Simões, A.M.; Battocchi, Dante; Tallman, Dennis E.; Bierwagen, Gordon P.

doi:10.1016/j.porgcoat.2008.02.007

Cited by 85 publications

(44 citation statements)

References 19 publications

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“…Thus, this technique has proven to be a very useful tool for studying a wide range of corrosion processes, including bimetallic corrosion, [1][2][3] dissolution of inclusions in alloys, [4][5][6] controlled generation of single pits in otherwise passive metals, [7][8][9] monitoring of precursor sites for pit nucleation in oxide layers [10][11][12] as well as detection of the metastable pitting regime [13,14] and the onset of corrosion processes from defective coatings. [15][16][17][18] Two recent reviews on further uses of SECM in the field of corrosion can be found in references [19,20].…”

Section: Introductionmentioning

confidence: 99%

Application of AC‐SECM in Corrosion Science: Local Visualisation of Inhibitor Films on Active Metals for Corrosion Protection

Pähler

Santana

Schuhmann

2010

Chemistry A European J

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The suitability of frequency-dependent alternating-current scanning electrochemical microscopy (4D AC-SECM) for investigation of thin passivating layers covering the surface of corrosion-inhibited metals has been demonstrated. Inhibition of copper corrosion by benzotriazole (BTAH) and methylbenzotriazole (MBTAH), which are effective inhibitors for this metal under many environmental conditions, was investigated. Strong dependencies were found for the AC z-approach curves with both the duration of the inhibitor treatment and the frequency of the AC excitation signal applied in AC-SECM. Both negative and positive feedback behaviours were observed in the AC approach curves for untreated copper and for Cu/BTAH and Cu/MBTAH samples. Negative feedback behaviour occurred in the low-frequency range, whereas a positive feedback effect was observed at higher frequencies. A threshold frequency related to the passage from negative to positive regimes could be determined in each case. The threshold frequency for inhibitor-modified samples was found always to be significantly higher than for the untreated metal, because the inhibitor film provides electrical insulation for the surface. Moreover, the threshold frequency increased with increasing surface coverage by the inhibitor. 4D AC-SECM was successfully applied to visualizing spatially resolved differences in local electrochemical activity between inhibitor-free and inhibitor-covered areas of the sample.

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Section: Introductionmentioning

confidence: 99%

Application of AC‐SECM in Corrosion Science: Local Visualisation of Inhibitor Films on Active Metals for Corrosion Protection

Pähler

Santana

Schuhmann

2010

Chemistry A European J

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“…A non-chrome/chrome replacement coating system would need to extend the life of existing Al-based assets and facilitate expanded use of economical aluminum alloys in both DoD and commercial applications [31]. Consequently, extensive research has been conducted in search of alternative technologies, such as anodization [32], sol-gel treatment [33][34][35], pigmented coatings [36], plasma polymer layers [37], conductive pigments/polymers [38,39], and pigment-based cathodic protection [40].…”

Section: Magnesium-rich Primermentioning

confidence: 99%

“…Simões et al investigated the mechanism of corrosion protection of AA2024 T3 by a Mg-rich coating using SVET and SECM [40,50]. SVET measured the evolution of pit activity with time under sacrificial protection, while SECM allowed indirect sensing of the cathodic activity above the electrodes.…”

Section: Performance and Mechanism Of Corrosion Protection By Mg-richmentioning

confidence: 99%

Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers) for Aluminum Alloys

Pathak

Mendon

Blanton

et al. 2012

Metals

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Abstract:Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers) as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD) to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

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“…[2][3][4][5][6] Corrosion protection for these coatings largely results from galvanic coupling between the Mg and Al alloy substrate enabling Mg particles dispersed in the polymer binder to serve as a sacrificial anode. Fundamental studies by Battocchi and coworkers 3 showed that corrosion protection provided by polymeric Mg-rich primers occurs in stages.…”

Section: Introductionmentioning

confidence: 99%

An investigation of the effects of polymer binder compositional variables on the corrosion control of aluminum alloys using magnesium-rich primers

Chisholm

et al. 2010

J Coat Technol Res

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It has recently been shown that magnesium (Mg) particles possessing a thin oxide surface layer can be used to produce primers that provide corrosion protection to aluminum (Al) alloys through a galvanic coupling mechanism. In addition to the Mg particles, polymer binder properties also affect corrosion protection. As a result, the effects of compositional variables associated with a two-component epoxy binder system on the ability of Mg-rich primers to protect an aerospace Al alloy were determined. The variables investigated were epoxy resin molecular mass, curing agent functionality, epoxy/NH ratio, and Mg content. All of the variables investigated had a significant effect on coating system performance and an optimized coating composition was identified that showed very good corrosion protection for at least 3,000 h of ASTM B117 salt spray exposure.

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Assessment of the corrosion protection of aluminium substrates by a Mg-rich primer: EIS, SVET and SECM study

Cited by 85 publications

References 19 publications

Application of AC‐SECM in Corrosion Science: Local Visualisation of Inhibitor Films on Active Metals for Corrosion Protection

Application of AC‐SECM in Corrosion Science: Local Visualisation of Inhibitor Films on Active Metals for Corrosion Protection

Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers) for Aluminum Alloys

An investigation of the effects of polymer binder compositional variables on the corrosion control of aluminum alloys using magnesium-rich primers

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