Corrosion properties of nickel-aluminium bronze in natural seawater—Effect of galvanic coupling to UNS S31603

Krogstad, Hedda Nordby; Johnsen, Roy

doi:10.1016/j.corsci.2017.03.016

Cited by 48 publications

(22 citation statements)

References 44 publications

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“…Conversely, a significant susceptibility of NAB to localized corrosion in fresh water appears at potentials which may be established by galvanic coupling to biofilm ennobled SS, as was observed in Ref. and which is known similarly from sea water applications …”

Section: Discussionmentioning

confidence: 61%

Design of a multichannel potentiostat and its application to corrosion testing of a nickel‐aluminum bronze

Linhardt

Kührer

Ball

et al. 2017

Materials & Corrosion

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A setup for potentiostatic testing of eight specimens at different potentials in a common electrolyte pool was developed. The potentiostat requires only one reference electrode and one counter electrode to control all working electrodes and its design is easily scalable with respect to the number of channels. The system is applied to assess the effect of chloride, sulfate, and bicarbonate in fresh water‐typical concentration on a nickel‐aluminum bronze, assuming some anodic polarization by stainless steel with and without microbially induced ennoblement. Chloride and sulfate activate corrosion, bicarbonate has a passivating effect, and its combination with chloride and sulfate promotes localized corrosion. The susceptibility of nickel‐aluminum bronze to localized corrosion may be high in fresh water when polarized anodically. Potentiostatic corrosion testing may yield practically relevant results for systems with slow kinetics.

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Section: Discussionmentioning

confidence: 61%

Design of a multichannel potentiostat and its application to corrosion testing of a nickel‐aluminum bronze

Linhardt

Kührer

Ball

et al. 2017

Materials & Corrosion

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“…18 Krogstad and Johnsen recently reported a similar behavior on NABs when galvanically coupled to stainless steels and exposed to natural seawater. 61 Selective corrosion attack, however, occurred on all κ precipitates below pH 4.0, leading to a reversal of the cathodic phase behavior in NAB. The reversal in corrosion behavior has also been reported inside crevice regions in a similar NAB by Wharton et al 17 The authors found that attack initiated at the α grains but propagated by κ-phase dissolution as the pH of the occluded region became more acidic.…”

Section: Discussionmentioning

confidence: 99%

“…9 In this mechanism, κ-phases serve as local cathodes and are protected by the formation of a self-protecting aluminum oxide layer. 2,9,61 The presence of ammonia facilitates the corrosion of the α-matrix by the formation of Cu (NH 3 ) 2+ and increases SCC susceptibility. [20][21][22] Nakhaie and coworkers conducted an SKPFM study on a cast NAB.…”

Section: Discussionmentioning

confidence: 99%

Unusual Correlation between SKPFM and Corrosion of Nickel Aluminum Bronzes

Iannuzzi

Vasanth

Frankel

2017

J. Electrochem. Soc.

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Scanning Kelvin probe force microscopy was used to investigate the influence of microstructure on the corrosion behavior of nickel aluminum bronzes in ammoniacal and NaCl solutions as well as under potential control in Na 2 SO 4 . The results showed an inverse correlation between the measured Volta potential difference and the observed corrosion behavior. In other words, the phase with initially higher Volta potential was preferentially attacked whereas those with the lowest Volta potential difference values remained intact. This behavior suggests that Volta potential difference maps in air cannot be universally correlated with practical nobility or reactivity in solution, as proposed by other investigators. Nickel aluminum bronzes.-Nickel aluminum bronzes (NABs) are Cu-based alloys with a typical nominal composition of 10 wt% Al, 5 wt% Ni, and 5 wt% Fe.1 NABs combine high strength, usually equal to or above that of medium carbon steels, i.e., up to 450 MPa (60 ksi), and toughness with adequate corrosion resistance to marine environments.2 Other attractive properties of NABs include their low magnetic permeability, excellent wear, galling, cavitation, and antifouling resistance, as well as being non-sparking and having a 10% lower density than steels. 3 In the maritime and oil and gas industries, NABs find numerous applications including valves and pumps, ship propellers, and heat exchangers. 3,4The physical metallurgy of NABs is extremely complex and strongly influenced by thermo-mechanical processing history. 5 The thermodynamics and kinetics of phase transformations in NABs have been studied in detail by Culpan and Rose, 6 Brezina, 7 Hasan and coworkers, 1,[8][9][10] and Wu et al., 11 among others. Although NABs solidify as a single body-centered cubic (bcc) β-phase, at room temperature they consist of a Cu-rich face-centered cubic (fcc) α-phase and several IMCs that some authors refer to collectively as κ-phase.1 Ni, Fe, and Mn combine with aluminum to form the various κ-phases, extending the apparent stability range of the α field and retarding the formation of the deleterious γ 2 -phase from the decomposition of β.6 In this regard, β decomposes to α and γ 2 during annealing or slow cooling below 565• C, which has plagued binary α/β aluminum bronzes with more than 9.4% Al. 7Under equilibrium cooling conditions, there are four types of IMCs in NABs, which are summarized in Table I. 1,5,6,8 Cast NABs with a Fe content above 4.4-5.0 wt% often present large, i.e., between 20 and 50 μm, dendritic-or rosette-shaped particles named κ I , which precipitate in the center of the α grains and do not exhibit a single crystal structure.8 In wrought and cast NABs, κ II precipitates, typically between 5 to 10 μm, form by decomposition of the high temperature β-phase. The κ II -phase is based on Fe 3 Al with Ni, Cu, and Mn substituting for iron. It often forms alongside the lamellar κ III eutectoid decomposition product.1,5 κ III is based on Ni-Al, with Fe, Cu, and Mn substituting for Ni. Likewise, equiaxed κ IV -phase pre...

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“…As can be seen in the figures, the surfaces of tested alloys consist of not only a wear track but also copper based oxides visible in different colour. Due to oxidation phenomenon on the surface that interacted with corrosive media, the cupric ions can form some components like Cu 2 (OH) 3 Cl, Cu 2 O and Cu 2 (OH) 3 Cl [21,22]. Worn surface characterization following wet sliding tests revealed that the surface contains accumulated corrosion products and as the total sliding distance increased the amount of deposits increased due to extended immersion time.…”

Section: Tribological Characterizationmentioning

confidence: 99%

Tribological Characterization of Al-bronzes Used as Mold Materials

Atapek

Çelik

Polat

et al. 2017

Archives of Foundry Engineering

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Among the copper based alloys, Cu-Al-X bronzes are commonly used as mold materials due to their superior physical and chemical properties. Mold materials suffer from both wear and corrosion, thus, it is necessary to know which one of the competitive phenomenon is dominant during the service conditions. In this study, tribo-corrosion behavior of CuAl10Ni5Fe4 and CuAl14Fe4Mn2Co alloys were studied and electrochemical measurements were carried out using three electrode system in 3.5 % NaCl solution in order to evaluate their corrosion resistance. In tribo-corrosion tests, alloys were tested against zirconia ball in 3.5 % NaCl solution, under 10N load with 0.04 m/s sliding speed during 300 and 600 m. The results indicate that (i) CuAl10Ni5Fe4 alloy is more resistant to NaCl solution compared to CuAl14Fe4Mn2Co alloy that has major galvanic cells within its matrix, (ii) although CuAl10Ni5Fe4 alloy has lower coefficient of friction value, it suffers from wear under dry sliding conditions, (iii) as the sliding distance increases, corrosion products on CuAl14Fe4Mn2Co surface increase at a higher rate compared to CuAl10Ni5Fe4 leading to a decrease in volume loss due to the lubricant effect of copper oxides.

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Corrosion properties of nickel-aluminium bronze in natural seawater—Effect of galvanic coupling to UNS S31603

Cited by 48 publications

References 44 publications

Design of a multichannel potentiostat and its application to corrosion testing of a nickel‐aluminum bronze

Design of a multichannel potentiostat and its application to corrosion testing of a nickel‐aluminum bronze

Unusual Correlation between SKPFM and Corrosion of Nickel Aluminum Bronzes

Tribological Characterization of Al-bronzes Used as Mold Materials

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