The anodic oxide film on iron in neutral solution

Satô, Norio; Kudô, Kiyokatsu; Noda, Tetsuji

doi:10.1016/0013-4686(71)85146-0

Cited by 127 publications

(63 citation statements)

References 11 publications

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“…This phenomenon has been attributed to the exponential variation of the resistivity as a function of the distance through the film [47]. Sato and all have also evoked the lack of three-dimensional long-range order due to small thickness of the films [48]. Some previous works [11,49] attribute this phenomenon to the variable conductivity of the film due to variable stoichiometry and to non-uniform distribution of doping species across the film thickness.…”

Section: Frequency Dependence Of the Capacitancementioning

confidence: 97%

Influence of surface roughness on the semiconducting properties of oxide films formed on 304 stainless steel

Hakiki

2008

J Appl Electrochem

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Oxide films were formed at 350°C in borate buffer solution on AISI 304 stainless steel priory abraded with wet SiC paper of different grit size. The films were characterised by Atomic Force Microscopy (AFM) and studied by capacitance, impedance, and photocurrent measurements. The images obtained by AFM microscopy show the evolution of the surface roughness of the films with increasing grit size. Capacitance measurements show that, in all cases, the electronic structure of the films is comparable to that of a p-n heterojunction. This structure is due to the development of space charge layers in the outer iron oxide region at the film/electrolyte interface and in the inner chromium oxide region at the film/metal interface. However, donor and acceptor densities are closely related to the surface roughness via the grit size of the wet SiC paper. An increase in capacitance leading to higher doping densities is manifested by an increase in grit size. These parameters are also frequency dependent. An investigation of the frequency dispersion in relation to the evolution of the surface roughness was performed by analysing the Bode plots through the impedance measurements. The photocurrent results, obtained for the oxide films formed on the different abraded AISI 304, show an increasing photoresponse with decreasing grit size. In spite of this, a constant value of the band gap energy was obtained whatever the oxide film considered. The photocurrent response near the absorption edge is also discussed. The photocurrent response at fixed wavelength and as a function of the applied potential is also influenced by the grit size.

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Section: Frequency Dependence Of the Capacitancementioning

confidence: 97%

Influence of surface roughness on the semiconducting properties of oxide films formed on 304 stainless steel

Hakiki

2008

J Appl Electrochem

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“…Kolotyrkin (16,17) emphasizes the possibility that chemisorbed oxygen ions are displaced by halogenide ions in reactions governed by processes of nucleation. Sat0 ( 18,19) considers the mechanical instability of thin films at high electric fields, and surface energies changing with the nature of chemisorption.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Pit Initiation at Passive Iron

Heusler

Fischer

1976

Materials & Corrosion

134

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Pit initiation at passive iron in borate and phthalate buffer solutions was investigated by separately measuring dissolution rates of Fe(III) and Fe(II) at rotating ring‐dis electrodes. The rate of Fe(III) dissolution grow linearly with the chloride concentration. Fe(II) appears simultaneously with the first pits. At a constant electrode potential positive to the critical pitting potential a stage of pit initiation is observed ending at the time ti of incubation after addition of chloride to the solution. The time ti is independent of the time of prior passivation. The potential dependence of ti described by a relation known from the theory of two‐dimensional nucleation. The physical meaning of this formal analogy is discussed. According to the dependence of ti on pH and chloride concentration the observed mechanism of pit initiation is possible only above a critical chloride concentration c=0.3 mM and below a critical pH 10.4. The absolute values of critical pitting potentials and the dependence of the critical pitting potentials on chloride concentration were found to be a function of the nature and the concentration of the supporting electrolyte. The influence of the supporting electrolyte on the time of incubation was also investigated.

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“…It is categorized in three main mechanisms: ͑i͒ The adsorption-induced thinning of the passive film that involves the competitive adsorption of the aggressive ions with hydroxyl groups at the passive film surface, 2,9,11-18 ͑ii͒ the penetration mechanism that involves the subsurface insertion and transport of the aggressive species to the metal/oxide interface 1,2,6,11 and that has been further developed in the point defect model 19,20 to form the penetrationinduced voiding mechanism, 21 and ͑iii͒ the inhibited healing mechanism that involves continuous events of breakdown and repair of the passive film and repair poisoning by the aggressive species. [22][23][24][25][26] All these models consider the passive layer as a simple uniform and homogeneous oxide ͑or hydroxide͒ film that blocks the migration of ions through the passive film.…”

mentioning

confidence: 99%

Breakdown Kinetics at Nanostructure Defects of Passive Films

Seyeux

Maurice

Marcus

2009

Electrochem. Solid-State Lett.

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Kinetics expressions for passivity breakdown have been determined based on a model taking into account the presence of intergranular defective sites in passive films. It is shown that depending on the interface at which the potential drop increase predominates, passivity breakdown can occur by enhanced dissolution ͑i.e., oxide thinning͒ at the oxide/electrolyte interface or by accelerated interfacial voiding at the metal/oxide interface. In all cases, the rate of the interfacial processes leading to passivity breakdown is increased at the intergranular defective sites of the passive film.

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The anodic oxide film on iron in neutral solution

Cited by 127 publications

References 11 publications

Influence of surface roughness on the semiconducting properties of oxide films formed on 304 stainless steel

Influence of surface roughness on the semiconducting properties of oxide films formed on 304 stainless steel

Kinetics of Pit Initiation at Passive Iron

Breakdown Kinetics at Nanostructure Defects of Passive Films

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