On the mechanism of the anodic dissolution of iron in acid solutions

Florianovich, G. M.; Sokolova, L. A.; Kolotyrkin, Ya.M.

doi:10.1016/0013-4686(67)80124-5

Cited by 75 publications

(26 citation statements)

References 20 publications

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“…Florianovich et al (13) conclude that anions in addition to OH-ions play a direct part in the anodic reaction; an effect consistent with a model in which specific adsorption of the anion changes the surface area for the Fe/Fe 2+ exchange has also been advanced (9, 10).…”

Section: Log [Fe E+ ] Ephmentioning

confidence: 91%

The Corrosion of Steel by Aqueous Solutions of Hydrogen Sulfide

Morris

Sampaleanu

Veysey

1980

J. Electrochem. Soc.

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Steel corrosion has been investigated through polarization studies in aqueous H2S systems of acid pH using a rotating disk electrode cell. H2S does not change the Tafel slopes of the anodic and cathodic processes. The anodic curves are shifted toward more negative potentials mainly due to the decrease of the reversible potential of iron, while the exchange current density appears to remain unchanged. The cathodic process maintains the reversible potential and the exchange current density of the H2S free system, but the H+ diffusion control gradually disappears. A corrosion current density dependence on the H2S concentration is found which matches that obtained from published weight-loss experiments. The product of corrosion, mackinawite is essentially nonadherent and in certain circumstances enhances the corrosion rate. A new method for the compensation of ohmic overpotential in polarization measurements is described.The corrosion of steel by aqueous H2S is a significant technical problem in two major industrial areas. In oil refineries and natural gas treatment facilities, the process conditions vary widely due to natural causes (1-4). Replication of the conditions for laboratory work is difficult. The Girdler-Sulphide (GS) process for the production of heavy water involves the use of H2S as the deuterium exchange agent. The process prescribes the basic pressure/temperature conditions, hence laboratory replication is simpler.This paper presents the results of studies of the corrosion of carbon steel by deaerated aqueous solutions of H2S at 25~176 using the potentiostatic polarization method and under long term (up to 1000 hr) dynamic exposure conditions. TheoryAccording to the electrochemical theory of corrosion, the corrosion process takes place at a mixed potential, Ecorr between the reversible potentials, ErevFe for the anodic process and ErevH for the cathodic process, in the absence of oxygen.The reversible potential, ErevFe for the Fe2+/Fe electrode is given generally by (5) ErevFe ~-~ --0.44 + 0.030 log lee 2+ ][1]For the particular case involving aqueous H2S solutions, the concentration of ferrous ions, [Fe 2+] is related to the first and second ionization constants of H2S, K1 and K=, the solubility product of FeS, Ks, and the Henry law constant, k, for the H2S solution. Inserting numerical values of K1, K2, and Ks equal to 9.1 • 10 -s, 1.1 • 10 -12, and 3.7 • 10 -19 at 18~ respectively (6), and k equal to 8.3 atm (mole liter -1)-1 (7) at 18~ gives ErevFe ~---0.39 --0.06 pH --0.03 log P~2s [2] where PH2S is the partial pressure of H2S. According to Hilbert et al. (8), iron with a high density of crystal imperfections dissolves by a catalyzed mechanism (CM) whereas iron with low surface activity dissolves by a noncatalyzed mechanism (NCM). The dissolution reaction is activation controlled with a Tafel slope b a ~_ 0.04 V/decade for the NCM (8-10) and b a ~_ 0.03 V/decade for the CM (11).The influence of the ferrous ion concentration on the reaction rate is disputed; Bockris and Reddy (12) claim an electro...

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Section: Log [Fe E+ ] Ephmentioning

confidence: 91%

The Corrosion of Steel by Aqueous Solutions of Hydrogen Sulfide

Morris

Sampaleanu

Veysey

1980

J. Electrochem. Soc.

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“…In sulphate-containing solutions the anodic dissolution proceeds according to a mechanism proposed by Florianovitch et al [73] …”

Section: Atmospheres Polluted With Somentioning

confidence: 99%

Atmospheric corrosion of mild steel

Morcillo¹,

Fuente²,

Díaz³

et al. 2011

REVMETAL

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The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morphology of steel corrosion products and corrosion product layers; and b) long-term atmospheric corrosion (>10 years). KeywordsAtmospheric corrosion; Mild steel; Long-term; Morphology; Review. corrosión atmosférica del acero suave resumenLa corrosión atmosférica del acero suave es un tema de gran amplitud que ha sido tratado por muchos autores en numerosas regiones del mundo. Este artículo de compilación incorpora publicaciones relevantes sobre esta temática, en particular sobre la naturaleza de los productos de corrosión atmosférica, mecanismos y cinética de los procesos de corrosión atmosférica, prestando una atención especial a dos aspectos sobre los que la información publicada ha sido menos abundante: a) morfología de los productos de corrosión del acero y capas de productos de corrosión, y b) corrosión atmosférica a larga duración (> 10 años).

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“…The author developed a model in which the anodic dissolution of iron takes place via two reactions, 11 at low potentials and 12 at higher potentials (for a complete list of his work see e.g. ref.…”

Section: Introductionmentioning

confidence: 99%

Anodic Tafel behaviour of mild steel in presence of inhibitors

Khalil

1992

Materialwissenschaft Werkst

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On the mechanism of the anodic dissolution of iron in acid solutions

Cited by 75 publications

References 20 publications

The Corrosion of Steel by Aqueous Solutions of Hydrogen Sulfide

The Corrosion of Steel by Aqueous Solutions of Hydrogen Sulfide

Atmospheric corrosion of mild steel

Anodic Tafel behaviour of mild steel in presence of inhibitors

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