Electrochemical impedance study on brass corrosion in NaCl and (NH4)2SO4 solutions during cyclic wet?dry conditions

El-Mahdy, Gamal A.

doi:10.1007/s10800-004-8347-1

Cited by 39 publications

(15 citation statements)

References 32 publications

(36 reference statements)

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“…This hypothesis is supported by the fact that both brochantite and simonkolleite have been recognized among the corrosion products of a modern brass attacked by artificial and natural sea water simulating chloride and sulphate attack [22]. Simonkolleite has also been identified in the study of brass corrosion in NaCl and (NH 4 ) 2 SO 4 during cyclic wet-dry conditions [23]. It should, however, be pointed out that the presence of the rare mineral simonkolleite in our sample is documented only by the presence of its strongest diffraction at d~7.85 Å, because its second strongest diffraction (d~2.67 Å) with the relative intensity I rel~2 5 falls to the region populated by the diffractions of atacamite.…”

Section: Resultsmentioning

confidence: 84%

X‐ray, synchrotron, and neutron diffraction analysis of Roman cavalry parade helmet fragment

Smrčok¹,

Petrík

Langer

et al. 2010

Cryst. Res. Technol.

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A partially corroded fragment of the neck guard of a Roman cavalry helmet excavated in the former military camp of Gerulata, a part of the Limes Romanus on the River Danube, was analysed by laboratory X-ray, synchrotron and neutron powder diffraction. The approximate phase composition determined by the neutron diffraction of the bulk, 82% (wt) of the copper alloy phase, 12 % (wt) of cuprite and 6% of nantokite indicate a significant degree of corrosion of the artefact. Elemental EDX analysis of cleaned surface showed that the chemical composition of the original alloy is 78 to 82 % (wt) of Cu and 21.4 to 16.5 % of Zn with minute amounts of Sn, Si and S. High contents of Cu and Zn with the negligible amount of Sn showed that the body of the helmet was made of brass and not of bronze as expected before. The amount of zinc in the copper alloy calculated from the refined lattice parameter agrees fairly well with the value determined by EDX. The most abundant phase in the synchrotron powder diffraction pattern of the corrosion products scrapped from the artefact is cuprite, but presence of atacamite, malachite, brochantite, nantokite, mixed Cu-Zn hydroxyl carbonates and probably also of simonkolleite (Zn 5 (OH) 8 Cl 2 .H 2 O ) have been detected. In contrast, the X-ray pattern taken directly from the surface of the artefact is dominated by atacamite with some traces of malachite and quartz. Because the penetration depth of laboratory X-rays is in order of tens of microns, the phase analysis based only on a diffraction pattern taken from a surface can lead to erroneous conclusions concerning the phase composition of the patina.

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Section: Resultsmentioning

confidence: 84%

X‐ray, synchrotron, and neutron diffraction analysis of Roman cavalry parade helmet fragment

Smrčok¹,

Petrík

Langer

et al. 2010

Cryst. Res. Technol.

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“…In the last decade the number of studies concerning the corrosion of archaeological bronze and brass objects has increased significantly [30][31][32][33][34]. Brass is extensively used in marine applications because of its mechanical workability, combined with corrosion resistance and good resistance to biofouling due to the high toxicity of cupric ions [35]. However, in some aggressive environments, brass can suffer from zinc dissolution, pitting corrosion and stress corrosion cracking [36].…”

Section: Corrosion and Conservation Of Brass Artefacts Retrieved Frommentioning

confidence: 99%

Analysis of naturally etched surface of brass sheathing from a nineteenth-century shipwreck

Ashkenazi

Inberg

Cvikel

2018

J min metall B Metall

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The Akko Tower Wreck is ently the remains of a 25-m-long merchant brig, dated to the first half of the nineteenth century. During the 2015 underwater excavation, a piece of brass sheet was retrieved from the shipwreck and its surface and bulk were examined by metallurgical analyses. The examinations revealed a unique example of almost two hundred years' natural etching, which took place in the sea underwater environment. The surface of the sheet was covered with different copper and zinc oxides, which were identified by XRD analysis. Observation of the naturally etched surface with multi-focal light microscopy and SEM-EDS analysis indicated a microstructure of annealed brass, similar to that of its bulk. S-OES chemical analysis of the bulk revealed a composition of 65.0 wt% Cu, 34.4 wt% Zn and 0.6 wt% Pb. Based on the thickness of the sheet and its good state of preservation, it is suggested that it was used as sheathing to protect the hull against marine organisms, and to improve the sailing qualities of the ship. The results provide further information about the Akko Tower shipwreck; and expand our knowledge regarding the corrosion processes and preservation of brass during a long burial period in marine environments.

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“…Apart from the uniform attack, the most common forms of brass corrosion are selective leaching (dezincification) [1], stress-corrosion cracking [2,3], and pitting. Selective leaching goes significantly faster in hydrochloric acid solutions, the rate of dezincification increases at higher temperatures [4]. In neutral chloride solutions, selective leaching occurs during the early stages of the corrosion process [5].…”

Section: Introductionmentioning

confidence: 99%

Corrosion of α-Brass in Solutions Containing Chloride Ions and 3-Mercaptoalkyl-5-amino-1H-1,2,4-triazoles

et al. 2019

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The protective effect of 3-mercaptoalkyl derivatives of 5-amino-1H-1,2,4-triazole against corrosion of α-brass in a chloride media was studied using polarization curves, electrochemical impedance spectroscopy, and full-scale corrosion testing. The brass electrode remains passive up to the activation potential, which is much higher than in solutions without organic additives, and it increases with the concentration of the inhibitor. The protection degree of all the studied inhibitors reaches its maximum of over 99% in solutions with the concentration of the inhibitor Cinh ≥ 0.10 mM. The protective effect increases with the length of the alkyl chain. All the studied derivatives are effective against atmospheric corrosion of α-brass. A protective film is formed on the brass surface, and it most probably includes oxides as well as complex compounds of zinc and copper with the molecules of the inhibitors. The impedance spectroscopy demonstrated that the presence of the inhibitor results in a decrease in the double-layer capacitance and an increase in the polarization resistance, which proves that the protective film actually forms on the brass surface. The quantum chemical analysis of the optimized molecular structures demonstrates that all the studied inhibitors should have a similar protective effect, which agrees with the experimental results.

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Electrochemical impedance study on brass corrosion in NaCl and (NH4)2SO4 solutions during cyclic wet?dry conditions

Cited by 39 publications

References 32 publications

X‐ray, synchrotron, and neutron diffraction analysis of Roman cavalry parade helmet fragment

X‐ray, synchrotron, and neutron diffraction analysis of Roman cavalry parade helmet fragment

Analysis of naturally etched surface of brass sheathing from a nineteenth-century shipwreck

Corrosion of α-Brass in Solutions Containing Chloride Ions and 3-Mercaptoalkyl-5-amino-1H-1,2,4-triazoles

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