Auger and XPS studies of cerium corrosion inhibition on 7075 aluminum alloy

Arnott, David; Ryan, N.E.; Hinton, Bruce; Sexton, B.A.; Hughés, A.E.

doi:10.1016/0378-5963(85)90056-x

Cited by 63 publications

(88 citation statements)

References 4 publications

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“…Influence of concentration on the effectiveness of corrosion inhibition.-It has been reported that the inhibition effectiveness of various cerium salts on AA7075-T6 11,12 and on AA2024-T3 16,23,24,26,34,35 is concentration dependent. For AA7075-T6 the optimal concentration of CeCl 3 is 1000 ppm (0.0027 M), while, for AA2024-T3, lower concentrations (e.g.…”

Section: Resultsmentioning

confidence: 99%

“…Since the initial studies by Hinton et al on AA7075-T6 in chloride solution containing CeCl 3 , [11][12][13] the majority of studies have been on AA2024-T3 [16][17][18][19][20][21][22][23][24][25][26] or other alloys like AA5052, 15 AA5083, [27][28][29] series AA6xxx, [30][31][32][33] AA8090 34 and Al metal. 35 The focus has been on the mechanism of inhibition, mainly by CeCl 3 15,17,18,20,21,26-29,35,36 and Ce(NO 3 ) 3 16,19,22,25,37 which both act as efficient inhibitors on aluminium alloys.…”

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confidence: 99%

“…5,[8][9][10] Among these, salts of rare earths -lanthanide and, especially, cerium salts -have been identified as being effective and environmentally acceptable. [11][12][13][14] Ce(III) salts are more soluble in water than Ce(IV) salts, which have rather low solubility. For most of these inhibitors, the optimal concentration was around 1000 ppm (≈2.68 mM).…”

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confidence: 99%

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Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

Rodič

Milošev

2015

J. Electrochem. Soc.

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The corrosion protection of pure aluminium and its alloys AA2024-T3 and AA7075-T6 has been studied in 0.1 M NaCl with and without the addition of Ce(III) chloride, Ce(III) nitrate, Ce(III) acetate and Ce(IV) sulfate. The study of Ce(III) acetate has been scarce but is here shown to be the most effective of the cerium salts studied, especially for AA7075-T6. The inhibition effectiveness of cerium salts is: Ce(III) acetate > Ce(III) chloride > Ce(III) nitrate for the metals studied. Ce(IV) sulfate does not inhibit corrosion. Electrochemical potentiodynamic measurements were used to investigate the mechanism of inhibition by cerium salts. Immersion tests in 0.1 M NaCl, with and without the addition of Ce(III) chloride and Ce(III) acetate, were performed to determine the effects of the inhibitors on the extent of corrosion damage at the surface of all three metals. For pure aluminium the inhibitory effectiveness was 78.5%, 82.6% and 84.0% in the presence of 3 mM Ce(III) nitrate, chloride and acetate, respectively. Aluminium and its alloys 2024-T3 (AA2024-T3) and 7075-T6 (AA7075-T6) generally have good resistance to corrosion under atmospheric conditions. They are used as construction materials, primarily in aircraft applications, because of their physical characteristics such as rigidity and high strength-to-weight ratio.1,2 The main differences between aluminium and its alloys lie in their mechanical and corrosion properties. Aluminium is cold worked, whereas AA2024-T3 and AA7075-T6 are heat treated and cold worked (T3) or artificially aged (T6). The reason for alloying aluminium is to increase strength by forming intermetallic particles, IMs.

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Section: Resultsmentioning

confidence: 99%

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Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

Rodič

Milošev

2015

J. Electrochem. Soc.

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“…This paper presents the preparation of HTC coatings on aluminum alloy AA 6061 specimens and the effect of bath composition, temperature and duration of treatment on the microstructure of the coating as well as on the corrosion behavior of uncoated and HTC coated Al alloy specimens. Rare earth compounds have been used as corrosion inhibitors of aluminum alloys [7][8][9][10] . Preliminary investigations revealed that chemical treatments to form lanthanide based coatings on Al alloys AA 1100 and AA 6061increased the corrosion resistance of the alloys [11][12][13] .…”

Section: Introductionmentioning

confidence: 99%

Effect of Processing on Microstructure and Corrosion Mitigating Properties of Hydrotalcite Coatings on AA 6061 Alloy

et al. 2015

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Pitting corrosion of the aluminium cladding of spent nuclear fuels stored in light water pools has been observed. To prevent this, coating of the Al cladding with hydrotalcite (HTC) was proposed. This paper presents the effect of chemical bath and processing parameters on microstructure and corrosion behavior of HTC coatings on alloy AA 6061 specimens. The HTC coating from the high temperature nitrate bath was homogeneous, thicker and consisted of well-defined intersecting platelets than that formed from the room temperature carbonate bath. Electrochemical polarization tests carried out with HTC coated AA 6061 specimens in 0.01 M NaCl revealed that specimens coated with HTC from the nitrate bath and further treated in a cerium salt solution were the most resistant to corrosion. Field tests in which un-coated and coated AA 6061 alloy coupons as well as full-size plates were exposed to the IEA-R1 reactor's spent fuel basin for duration of up to 14 months further corroborated the high corrosion resistance imparted by the high temperature HTC + Ce coating. The mechanism by which the HTC coating and cerium protect the Al alloy is discussed.

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“…There have been extensive efforts to develop environmentally friendly alternative inhibitors, and rare earth metals (REMs) such as cerium, praseodymium and lanthanum have attracted much attention. [18][19][20][21][22][23] REM inhibition was first demonstrated in experiments with AA7075, wherein the ability to inhibit corrosion was evaluated by mass loss and linear polarization measurements. 18 Corrosion rates were decreased dramatically by the addition of 100 ppm CeCl 3 , with the level of inhibition remaining constant up to 1000 ppm.…”

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confidence: 99%

Microelectrochemical Characterization of the Effect of Rare Earth Inhibitors on the Localized Corrosion of AA2024-T3

Hurley

Buchheit

2015

J. Electrochem. Soc.

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The inhibition effect of three rare earth metals (REMs), Ce 3+ , La 3+ and Pr 3+ , on the electrochemical properties of synthesized single-phase intermetallic compounds (IMCs) representing phases commonly found in AA2024-T3 were studied and compared with chromate inhibition. REM additions had little effect on corrosion potential, pitting potential and i corr in short-term tests. This is in contrast to effects observed with chromate inhibitor additions where the pitting potential was seen to increase dramatically. All three REMs decreased the oxygen reduction reaction (ORR) kinetics on each synthesized phase, but none as much as chromate. The results in these studies are consistent with the idea that inhibition by REMs results from hydroxide precipitation at IMCs due to a local pH increase associated with the ORR. As hydroxide precipitation is a comparatively slow process, REMs cannot inhibit the initial dealloying of S phase, leading to the formation of dealloyed layers under hydroxide layers. Once the hydroxide precipitate forms, the subsequent corrosion of S phase is strongly inhibited. The dependence of inhibition on the formation of hydroxide deposits demonstrates that REMs are "slow" inhibitors, which must be considered in their applications. Alloying elements such as Cu and Mg are intentionally added to AA2024-T3 to improve mechanical properties such as strength and toughness.1 However, their solubility in Al is low and these elements precipitate to form intermetallic compound (IMC) particles during solidification processing and heat-treatment.1-3 These IMCs usually possess electrochemical properties different from the surrounding matrix, and can be selectively dissolved or induce localized galvanic corrosion.4-6 Passive or dealloyed films on an IMC particle surface can protect the particle from corrosion, but they can rupture or deteriorate under aggressive environmental conditions or mechanical stress, leading to increased electrochemical reactivity and localized corrosion.7-9 Inhibitors have been used to stifle the localized corrosion and improve corrosion resistance, thereby extending the service time of aluminum alloys. 10 Chromate is a noteworthy inhibitor with the ability to self-heal if chemical or mechanical damage occurs. 11-17Unfortunately, chromate is toxic and carcinogenic in nature and its application is limited. There have been extensive efforts to develop environmentally friendly alternative inhibitors, and rare earth metals (REMs) such as cerium, praseodymium and lanthanum have attracted much attention. [18][19][20][21][22][23] REM inhibition was first demonstrated in experiments with AA7075, wherein the ability to inhibit corrosion was evaluated by mass loss and linear polarization measurements.18 Corrosion rates were decreased dramatically by the addition of 100 ppm CeCl 3 , with the level of inhibition remaining constant up to 1000 ppm. Similar inhibition efficiencies and trends were observed for other lanthanide salts including YCl 3 , LaCl 3 , PrCl 3 and NdCl 3 . 24 In all cases, inh...

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Auger and XPS studies of cerium corrosion inhibition on 7075 aluminum alloy

Cited by 63 publications

References 4 publications

Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

Corrosion Inhibition of Pure Aluminium and Alloys AA2024-T3 and AA7075-T6 by Cerium(III) and Cerium(IV) Salts

Effect of Processing on Microstructure and Corrosion Mitigating Properties of Hydrotalcite Coatings on AA 6061 Alloy

Microelectrochemical Characterization of the Effect of Rare Earth Inhibitors on the Localized Corrosion of AA2024-T3

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