Anodic behaviour of carbon steel in concentrated NaOH solutions

Zou, Jin-Yun; Chin, D.‐T.

doi:10.1016/0013-4686(88)80164-6

Cited by 51 publications

(36 citation statements)

References 20 publications

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“…Both these phenomena may be explained in terms of enhanced convective mass transfer between the electrode surface and the bulk of the electrolyte solution. While in the case of the anodic potential course it results in enhanced chemical attack by OH -ions on the oxo-hydroxide layer covering the electrode surface [11], during the cathodic potential sweep the removal of ferrate and intermediates from the anode surface reduces the extent of the electrode reactions corresponding to the individual current peaks.…”

Section: Voltammetric Experimentsmentioning

confidence: 99%

The influence of electrolyte composition on electrochemical ferrate(VI) synthesis. Part III: anodic dissolution kinetics of a white cast iron anode rich in iron carbide

Mácová

Bouzek

2012

J Appl Electrochem

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The anolyte composition and process temperature could improve the kinetics of iron anode dissolution and subsequent ferrate(VI) production significantly. This also holds for the anode composition. Following pure iron and silicon-rich steel (SRS), white cast iron (WCI) was the last representative of anode material tested that is typically used to produce ferrate(VI). Using anolytes 14 M NaOH, 14 M KOH, and mixtures thereof, the systems were studied by potentiodynamic methods, electrochemical impedance spectroscopy, and batch electrolysis experiments. Additionally, metallographic analysis of the material was performed. The dissolution kinetics increases with increasing temperature and also, at 60°C, with increasing K ? content in the anolyte, but less progressively than in the case of SRS. Similar to SRS, WCI also easily dissolves into ferrate(VI) even at 20°C in pure NaOH, thus indicating the inferior protective properties of oxo-hydroxide surface layers. In general, a maximum current efficiency of approx. 60 % was obtained at 60°C in pure KOH solution. The authors conclude that, at 60°C, the high efficiency of the synthesis is caused by the low protective properties of the oxo-hydroxide surface layer caused by the preferential dissolution of cementite and at the same time by the precipitation of the potassium salt of the product in the electrolyte immediately after its formation. This minimizes the effect of its decomposition.

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Section: Voltammetric Experimentsmentioning

confidence: 99%

The influence of electrolyte composition on electrochemical ferrate(VI) synthesis. Part III: anodic dissolution kinetics of a white cast iron anode rich in iron carbide

Mácová

Bouzek

2012

J Appl Electrochem

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“…Many investigations were carried out using highly alkaline solutions [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] or using buffer solutions as carbonate/bicarbonate [19][20][21][22][23][24][25][26] or borate buffer [27][28][29][30][31][32] when a constant and not very high pH is desirable. Many products have been identified as resulting from the anodic polarization of iron at different potentials, by different surface analysis techniques [6][7][8][9][10][11][12][13]22,26,[33][34][35][36][37][38][39][40]…”

Section: Introductionmentioning

confidence: 99%

“…Many products have been identified as resulting from the anodic polarization of iron at different potentials, by different surface analysis techniques [6][7][8][9][10][11][12][13]22,26,[33][34][35][36][37][38][39][40][41][42][43][44][45] . Several electrochemical techniques have also been used to investigate the kinetics of the formation of these products and among them cyclic voltammetry is one of the most used [2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22] . The surface analysis techniques that perform in-situ analysis have the great advantage of avoiding decomposition and/or dehydration of products formed which is inevitable with ex-situ analysis due to the high vacuum conditions and to the heating promoted by electron bombardment 1,14,28,[33][34][35][36]…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Behaviour of Iron in NaOH 0.01 mol/L Solutions Containing Variable Amounts of Silicate

Amaral¹,

Müller²

1999

J. Braz. Chem. Soc.

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Ciclos voltamétricos repetitivos do ferro em soluções de NaOH contendo concentrações variáveis de silicato entre 10 ppm e 1500 ppm, mostram comportamentos diferentes da primeira varredura quando comparada com as subsequentes, em todas as soluções testadas. Esta diferença indica uma modificação do processo de formação do filme com a ciclagem. Foi observada uma transição do perfil i/E entre 10 ppm e 100 ppm de silicato o que permite formular considerações sobre a incorporação de silicato ao filme.Repetitive voltammetric cycling of iron in NaOH solutions containing variable silicate concentrations between 10 ppm and 1500 ppm, shows different behaviour for the first scan when compared to the following ones in all studied solutions. This difference indicates a modification on the film formation process. A transition in the i/E profile between 10 ppm and 100 ppm of silicate was observed allowing considerations about silicate incorporation to be formulated.

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“…In presence of various anions, iron dissolution was explained invoking the participation of SCTC and mechanistic schemes. Many studies about active dissolution and passivation were carried in alkaline solution [3][4][5][6][7][8][9][10][11][12] and many electrochemical studies have been investigating the behaviour of iron in aqueous solution. Several mechanisms have been suggested [3][4][5][6][7][8][9] [4,5,14].…”

Section: Introductionmentioning

confidence: 99%

“…Many studies about active dissolution and passivation were carried in alkaline solution [3][4][5][6][7][8][9][10][11][12] and many electrochemical studies have been investigating the behaviour of iron in aqueous solution. Several mechanisms have been suggested [3][4][5][6][7][8][9] [4,5,14]. Under potentiodynamic conditions, the first anodic peak is specifically related to Fe(OH) 2 formation and the second peak to Fe(OH) 2 with three dimensional oxide film, and the third peak to FeOOH formation [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Role of Halides on the Passivation of Iron in Alkaline Buffer Solutions

Begum

Basha

Muralidharan

2010

Port. Electrochim. Acta

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Cyclic voltammetric studies were carried out on pure iron in alkaline borate and phosphate buffer solutions at pH 10.8. At higher potentials, on anodic polarization, iron forms FeB 4 O 7 and FeOOH in borate buffer, and FeHPO 4 in phosphate buffer which got converted to higher valency phosphates. In phosphate solutions, in presence of halides, the interfacial diffusion layer turned to be cation selective outer sublayer and an anion selective inner sublayer, and in borate solutions a precipitate layer of metal oxyhydroxide was formed, which was anion selective, and anions adsorb on this.

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Anodic behaviour of carbon steel in concentrated NaOH solutions

Cited by 51 publications

References 20 publications

The influence of electrolyte composition on electrochemical ferrate(VI) synthesis. Part III: anodic dissolution kinetics of a white cast iron anode rich in iron carbide

The influence of electrolyte composition on electrochemical ferrate(VI) synthesis. Part III: anodic dissolution kinetics of a white cast iron anode rich in iron carbide

Electrochemical Behaviour of Iron in NaOH 0.01 mol/L Solutions Containing Variable Amounts of Silicate

Role of Halides on the Passivation of Iron in Alkaline Buffer Solutions

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