Effect of chromate primer on corrosion fatigue in aluminum alloy 7075

Dorman, Sarah E. Galyon; Lee, Yong-Won

doi:10.1016/j.proeng.2011.04.203

Cited by 16 publications

(7 citation statements)

References 3 publications

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“…This supposition agrees with the results of previous work on chromate effects on the crack nucleation and early stage crack propagation on AA7XXX alloys exposed to chloride solutions. [68][69][70][71] Chromate was shown to improve the pit-to-crack transition life through slowing the development of pitting corrosion, as well as slow the growth rates of small cracks, attributed to the formation of Cr 3+ -rich films which were posited to act as barrier to hydrogen production and subsequent embrittlement of the crack tip. [68][69][70][71] It should be noted that the results of the present work may be different when extended to complex geometries, such as fastener holes, where the bare noble fasteners and the adjacent corroding Al matrix located far away from the surface may not benefit from the chromate inhibition concentrated at the surface.…”

Section: Discussionmentioning

confidence: 99%

An RDE Approach to Investigate the Influence of Chromate on the Cathodic Kinetics on 7XXX Series Al Alloys under Simulated Thin Film Electrolytes

Charles-Granville

Liu

Scully

et al. 2020

J. Electrochem. Soc.

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The effect of sodium chromate on the cathodic current availability pertinent to the micro-galvanic-induced corrosion of high-strength AA7XXX alloys under simulated thin electrolyte films representative of atmospheric conditions was investigated utilizing a combination of electrochemical and surface characterization techniques. The rotating disk electrode technique provided a means to simulate the effects of water layer thickness to differentiate thin film conditions from full immersion conditions, and enabled the study of the mass-transport-limited oxygen reduction reaction (ORR) on AA7XXX alloys as a function of chromate concentration. The ORR current density decreased by up to two orders of magnitude upon addition of 10 mM chromate, however, the degree of inhibition was observed to depend on the Cu content of the alloy. Chromate was reduced irreversibly to form a Cr3+-rich film on the alloy surface that blocked cathodic sites and hindered ORR. This film was confirmed by X-ray photoelectron spectroscopic characterization of the chemistry and thickness of the chromate-induced layer formed on the specimens after exposure to chromate. The layer was approximately 13 nm in thickness and consisted of mixed Cr3+/Cr6+ oxides with some metallic Cr. Studies on a Pt electrode demonstrated the intrinsic ability of chromate as an effective inhibitor for ORR.

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Section: Discussionmentioning

confidence: 99%

An RDE Approach to Investigate the Influence of Chromate on the Cathodic Kinetics on 7XXX Series Al Alloys under Simulated Thin Film Electrolytes

Charles-Granville

Liu

Scully

et al. 2020

J. Electrochem. Soc.

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“…In following paragraphs, a literature review could be seen for fatigue properties of aluminum alloys [4][5][6][7][8][9][10][11][12][13] and aluminum-matrix composites [14][15][16][17]. In addition, some other articles [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] have been reviewed for corrosion-fatigue properties of aluminum alloys. Ueno et al [4] studied fatigue properties of Al-Si-Cu alloys in ambient air and vacuum environments.…”

Section: Introductionmentioning

confidence: 99%

“…It was depicted from fractographic evidences that the decrease in the lifetime under high-cycle fatigue regims was due to premature the crack initiation, which was from corrosion pits, formed on the surface of the sample. Galyon Dorman and Lee [19] studied the chromate primer effect on the corrosion-fatigue behavior in the AA7075-T651 aluminum alloy. Their tests in the pure water suggested that the ratio of chloride to chromate had in uences on the e cacy of chromate.…”

Section: Introductionmentioning

confidence: 99%

Corrosion Effects on High‐cycle Fatigue Lifetime and Fracture Behavior for Heat‐treated Aluminum‐matrix Nano‐clay‐composite Compared to Piston Aluminum Alloy

Aroo

Azadi

2021

Silicon

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In this research, the corrosion effect has been investigated on the high-cycle fatigue lifetime and the fracture behavior for the heat-treated aluminum-matrix nano-clay-composite and piston aluminum alloys. For this objective, after fabricating stir-casted nano-clay-composite, standard samples were machined and rotary bending fatigue tests were performed. To study the corrosion effect, some specimens were corroded in in the 0.00235% H 2 SO 4 solution after 200 hours and then, they were tested under cyclic bending loading. Due to increase in the hardness by adding nano-clay particles and the heat treatment, higher fatigue strength occurred, compared to the base material. Nano-clay particles shortened the fatigue lifetime; however, this effect was less in the corrosion-fatigue lifetime. Moreover, the failure mechanism was the brittle fracture behavior due to the observation of quasi-cleavage and cleavage marks.

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“…To increase AA2024‐T3 resistance against corrosion, application of protective coating systems was crucial . Usually, several procedures were followed: a surface pretreatment, a conversion coating, and a paint system.…”

Section: Introductionmentioning

confidence: 99%

“…However, the use of chromates is increasingly reduced because of the carcinogen and toxic nature of Cr 6+ . Currently, the challenge is to find out more acceptable, friendly, and less harmful alternative treatments with anticorrosion performances comparable or better than Cr (VI)‐based solutions …”

Section: Introductionmentioning

confidence: 99%

Effect of AA2024‐T3 surface pretreatment on the physicochemical properties and the anticorrosion performance of poly(γ‐glycidoxypropyltrimethoxysilane) sol‐gel coating

Mrad

Amor

Dhouibi

et al. 2017

Surface & Interface Analysis

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This study investigated the dependence of the anticorrosion performance of a poly(γglycidoxypropyltrimethoxysilane) (poly(γ-GPTMS)) sol-gel coating on AA2024-T3 aluminum alloy surface state. Two different AA2024-T3 surface pretreatment procedures were tested: a degreasing with acetone and a chemical multistep etching process (industrial chemical etching pretreatment). Poly(γ-GPTMS) coatings were deposited onto both pretreated surfaces using the dip-coating technique. Surfaces were characterized principally by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared attenuated total reflectance, contact angles, and roughness measurements. Moreover, for the coated AA2024-T3 surfaces, a pull-off test was used to evaluate the poly(γ-GPTMS) adhesion to the pretreated surface. Bare surface properties depended on the applied pretreatment. The chemically etched surface was the roughest and the most concentrated in hydroxyl groups. In addition, comparatively to the degreased surface, it has a more hydrophobic character. Poly(γ-GPTMS) coating revealed an uneven nature and a poor adhesion once it was deposited onto the degreased surface. Coatings anticorrosion performances were evaluated using electrochemical impedance spectroscopy measurements (EIS). Electrochemical impedance spectroscopy data proved that the sol-gel coating applied onto the chemically etched surface had better anticorrosion performance.

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Effect of chromate primer on corrosion fatigue in aluminum alloy 7075

Cited by 16 publications

References 3 publications

An RDE Approach to Investigate the Influence of Chromate on the Cathodic Kinetics on 7XXX Series Al Alloys under Simulated Thin Film Electrolytes

An RDE Approach to Investigate the Influence of Chromate on the Cathodic Kinetics on 7XXX Series Al Alloys under Simulated Thin Film Electrolytes

Corrosion Effects on High‐cycle Fatigue Lifetime and Fracture Behavior for Heat‐treated Aluminum‐matrix Nano‐clay‐composite Compared to Piston Aluminum Alloy

Effect of AA2024‐T3 surface pretreatment on the physicochemical properties and the anticorrosion performance of poly(γ‐glycidoxypropyltrimethoxysilane) sol‐gel coating

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