Electrochemical and spectroscopic studies on dezincification of α-brass

Saber, T.M.H.; Warraky, A. A. El

doi:10.1016/0011-9164(93)80123-5

Cited by 18 publications

(18 citation statements)

References 13 publications

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“…This is opposite to the general acceleration of dezincification in the presence of chloride ions as time elapsed. At pH 8.5 Z f agreed with % Zn in the alloy and indicated the significant contribution of zinc dissolution as HZnO À 2 and ZnCl 2 [3,8]. This is why the most reactive alloy at pH 2.4 and 7.0 with the least % Zn became the least reactive in both corrosion and dezincification at pH 8.5.…”

Section: Neutral and Slightly Alkaline Solutionssupporting

confidence: 51%

“…Close to the corroding surface, a solid state diffusion layer inside the alloy is established (SS Diffusion Layer in the model), the thickness of which is assumed to increase with corrosion time. The outer most part of this layer is poor in zinc due to the initial fast leaching of zinc, as reported in previous studies at times less than one hour [3,5,6,8]. One may assume that the concentration of zinc atoms decreases on approaching the surface from the alloy bulk, based on the diminishing Z f values with corrosion time [3,5,6,8].…”

Section: The Proposed Dezincification Modelmentioning

confidence: 75%

“…The difference between DW SA and DW Bl increased as corrosion time increased due to thickening of the corrosion product layer. Previous X-ray photo-electron spectroscopy (XPS) and Auger electron spectroscopy (AES) results showed that the corrosion product layer is composed mainly of Cu 2 O and ZnO with different proportions, depending on the solution pH, corrosion period, chloride content, alloy composition and electrode potential [3,4,8]. Neither DW SA nor DW Bl can be used for an accurate estimation of the corrosion rate because soluble and insoluble products contribute to the total corrosion rate.…”

Section: Electrochemical Polarizationmentioning

confidence: 99%

“…Cuprous chloride complex ion CuCl À 2 was assumed to accelerate the dezincification of brass in hydrochloric acid via catalyzing the dissolution of copper into cupric species, which consequently deposited on the expense of zinc dissolution [6]. Disproportionation of Cu(I) species into Cu and Cu 2 was suggested as a probable process for dezincification [3,8,16] in chloride solutions, though the detailed study due to Newman et al [1,25] dismissed Cu(I) disproportionation. Most studies on the dezincification in chloride environments extended for periods no longer than few hours although dezincification at much longer periods seems interesting from the technical point of view.…”

Section: Introductionmentioning

confidence: 99%

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A model for prolonged dezincification ofα-brasses in 3% sodium chloride buffer solutions at different pH values

Rehan¹,

Al-Moubarak²,

Alrafai³

2001

Materials and Corrosion

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Dezincification behaviour of three commercial α‐brasses (33–37% Zn) in acetate buffer solutions containing 0.5 M sodium chloride was studied by weight loss, solution analysis and electrochemical polarization over a period of time extended for four weeks. The corrosion behaviour in the same solutions without chloride was also studied to explore the role of chloride in the dezincification. The presence of chloride led to a severe dezincification, which increased as time increased in contrast to chloride‐free solutions. The corrosion rate, however, was insensitive to the presence of chloride. The dezincification factor in chloride solutions increased in the order: pH 7.0 < pH 8.5 < pH 2.4 (order of increasing Zn dissolution rate) while the corrosion rate followed the order: pH 8.5 < pH 7.0 < pH 2.4 (order of increasing O2 and H+ reduction rates). Corrosion and dezincification was not a simple function of % Zn in the alloy. A model was proposed to explain the autocatalytic dezincification in chloride solutions and important elements in the model are: the production, disproportionation and redeposition of cuprous chloride complexes, growth of a spongy copper layer on the corroding alloy and establishment of an increasing number of microgalvanic cells.

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Section: Neutral and Slightly Alkaline Solutionssupporting

confidence: 51%

Section: The Proposed Dezincification Modelmentioning

confidence: 75%

Section: Electrochemical Polarizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A model for prolonged dezincification ofα-brasses in 3% sodium chloride buffer solutions at different pH values

Rehan¹,

Al-Moubarak²,

Alrafai³

2001

Materials and Corrosion

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“…6) For the pure Cu-Zn binary system in chloride media, the majority of publications have been focused on the dealloying process. 7,8) Brass corrosion in the natural and synthetic seawater is much less investigated.…”

Section: Introductionmentioning

confidence: 99%

The Corrosion Behavior of an Ag43Cu37Zn20 Alloy in the Natural Seawaters

et al. 2015

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We investigated the effects of natural seawater on the corrosion of an Ag43Cu37Zn20 alloy. The alloy was a commercial brazing filler alloy of composition (BS1845:1984 Ag5) and belongs to the class of Cd-free silver brazing alloys. The Ag-Cu-Zn system is corrosion resistant in chloride solutions has not been widely examined. In this study, the corrosion behavior of the alloy has been investigated using the open circuit potential measurements, Tafel plots and anodic potentiodynamic curves. By comparing different samples of marine water indicates that salinity is the primary influence on corrosion behavior near the open circuit potential. At higher anodic potentials, the impact of mineral composition becomes significant.

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Corrosion behaviour of copper in LiBr solutions – surface examination

Meleigy¹,

Elhamid²,

Warraky

2015

Materialwissenschaft Werkst

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Optical microscope (O.M) and scanning electron microscope (SEM) equipped with energy dispersive X‐ray (EDX) were used to follow the changes that occurred on the surfaces of copper after treated electrochemically in concentrated solutions of LiBr (up to 9 M). Results showed the existence of protective film of CuO and Cu(OH)2 which are recorded during the passive film formation in 5 × 10–1 M LiBr at 200 mV. At 1 M LiBr and during the partial passive region (600 mV) a porous film of Cu2O with a small ratio of CuOH and Cu(OH)2 were detected which confirmed the higher current density recorded. On the other hand and at the same concentration (1 M LiBr at 1000 mV), surface examination confirmed the detection of CuBr2 with small ratio of CuO which explain the deleterious effect of bromide and the autocatalytic dissolution of Cu at this higher potential. At higher concentrations from 4 to 9 M, the film formed is non homogeneous with a more porous structure which is mainly CuBr and some area of the film suffered from cracking. This proves the general dissolution through the complexing formation of soluble CuBr2–.

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Electrochemical and spectroscopic studies on dezincification of α-brass

Cited by 18 publications

References 13 publications

A model for prolonged dezincification ofα-brasses in 3% sodium chloride buffer solutions at different pH values

A model for prolonged dezincification ofα-brasses in 3% sodium chloride buffer solutions at different pH values

The Corrosion Behavior of an Ag43Cu37Zn20 Alloy in the Natural Seawaters

Corrosion behaviour of copper in LiBr solutions – surface examination

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