The shipboard exposure testing of aircraft materials

Tankins, Edwin S.; Kozol, Joseph; Lee, E. W.

doi:10.1007/bf03221254

Cited by 3 publications

(2 citation statements)

References 2 publications

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“…Except in the study of bulk solution pH effects, the solution pH was usually set to be either 3.0 or 11.0. The pH value of 3.0 was chosen since it closely resembles the pH for an accelerated corrosion test of Al 2024 in an offshore environment . On the other hand, the effect of alkaline exposure on the interfacial properties of the alloy is also of importance since an alkaline environment develops beneath the disbonding organic coatings.…”

Section: Introductionmentioning

confidence: 99%

Sorption of Sulfate and Chloride Anions on a Well-Characterized Al 2024 Electrode

et al. 1998

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We studied sorption processes, adsorption and incorporation, of sulfate and chloride anions on the surface of well-characterized aluminum 2024 alloy using electrochemical, radiochemical, and ultrahigh-vacuum spectroscopic techniques. The measurements were carried out at an open-circuit potential and in the electrode potential range on the negative side of the open-circuit potential (cathodic polarization conditions), at various pH values. The focus was on sorption reversibility as well as on the relationship between anion's surface concentration and the electrode potential. We have found that sorption of sulfate anion is controlled by pH, surface charge, and the stability of aluminum oxide films. We have also found that adsorption of chloride is weaker than sulfate and is more irreversible since chloride incorporation occurs more readily than sulfate. The change in the alloy surface composition and morphology induced by the electrochemical treatment and anion adsorption was monitored by scanning Auger microscopy and energy-dispersive X-ray spectroscopy. The characterization exhibits copper-rich intrusions and extrusions that may act as either local cathodes or anodes in the overall alloy dissolution process. The distribution and evolution of such Cu-rich inclusions under studied experimental conditions were monitored and are reported. The dissolution of aluminum from the alloy affects both sulfate and chloride adsorption/incorporation processes. While sulfate and chloride adsorption have no effect on cathodic current measured in the studied electrode potential range, the high anion surface concentration may have a detrimental effect on the alloy stability, particularly when the beneficial influence of the cathodic polarization (protection) ends.

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Section: Introductionmentioning

confidence: 99%

Sorption of Sulfate and Chloride Anions on a Well-Characterized Al 2024 Electrode

et al. 1998

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“…For carrier‐based aircraft, the combination of exhaust gases and marine salt spray forms a highly acid wet liquid membrane with a pH value of 2.4–4.0, which makes the aircraft components suffer serious environmental corrosion. [ 23,24 ] 7B04 aluminum alloy is one kind of Al–Zn–Mg–Cu series aluminum alloy and is similar to 7075 aluminum alloy in compositions and properties. [ 25 ] It has been widely used in load‐bearing structures, such as the front fuselage and central wing, of aircraft.…”

Section: Introductionmentioning

confidence: 99%

The long‐term corrosion performance and adhesion properties of 7B04 aluminum alloy/anodic film/epoxy primer system in acidic NaCl solution

Zhang¹,

Chen²,

Zhang³

et al. 2021

Materials & Corrosion

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The deterioration process and corrosion protective effect of 7B04 aluminum alloy/anodic film/epoxy primer system in acidic NaCl solution for 3024 h were investigated by optical/electron microscopes, electrochemical impedance spectroscopy (EIS), scanning Kelvin probe (SKP), and pull‐off adhesion test. The results showed that the protective system of anodic film and epoxy primer can protect aluminum alloy from pitting corrosion after immersion for 2352 h. According to the response characteristics of EIS and SKP, different stages of the failure process could be identified. During the first 100 h of immersion, the water transport in the coating followed Fickian law, and the water diffusion coefficient was 2.03 × 10−11 cm2/s, which demonstrated that the coating has good impermeability. Anodizing and coating treatment improved the open circuit potential and impedance of 7B04 aluminum alloy and made the distribution of Volta potential more uniform. The decreasing rate of wet adhesion strength was first fast and then slow, which was similar to the variation rule of coating resistance. The anodic film enhanced the adhesion between epoxy primer and substrate so that the failure nature of the adhesion test was mainly the cohesive failure of the epoxy primer.

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