Characterization of the film formed on iron in borate solution by electrochemical impedance spectroscopy

Martini, Emilse Maria Agostini; Müller, Ivan

doi:10.1016/s0010-938x(99)00064-5

Cited by 148 publications

(50 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The steady-state current density is approximately 6.8 μA cm −2 . two series capacitances: the space charge capacitance (C SC ) at the film/solution interface and the classical Helmholtz capacitance (C H ) [8]:…”

Section: Polarization Behaviormentioning

confidence: 99%

See 1 more Smart Citation

Diffusivity of Point Defects in the Passive Film on Stainless Steel

Fattah‐alhosseini

Alemi

Banaei

2011

International Journal of Electrochemistry

View full text Add to dashboard Cite

The semiconductor properties of passive films formed on AISI 316 stainless steel in sulfuric acid solution were studied by employing Mott-Schottky analysis in conjunction with the point defect model. The donor density of the passive films, which can be estimated by the Mott-Schottky plots, changes depending on the film formation potentials. Based on the Mott-Schottky analysis, an exponential relationship between donor density and the film formation potentials of the passive films was developed. The results showed that the donor densities evaluated from Mott-Schottky plots are in the range 2-3 × 10 21 cm −3 and decreased with the film formation potential. By assuming that the donors are oxygen ion vacancies and/or cation interstitials, the diffusion coefficient of the donors, (D O ), is calculated to be approximately 3.12 × 10 −16 cm 2 /s.

show abstract

Section: Polarization Behaviormentioning

confidence: 99%

“…Given a correct value of C SC capacitance, the electronic properties are usually deduced from the Mott-Schottky relation [8,9] as follows:…”

Section: Mott-schottkymentioning

confidence: 99%

Diffusivity of Point Defects in the Passive Film on Stainless Steel

Fattah‐alhosseini

Alemi

Banaei

2011

International Journal of Electrochemistry

View full text Add to dashboard Cite

show abstract

“…5,39,40 From the analysis above, this method was closer to the real C film , as it avoided frequency dispersion and, more importantly, ensured the potential drop into the film. But one essential problem is whether C film can be treated as C SC or not.…”

Section: Discussionmentioning

confidence: 99%

Rediscovering Mott-Schottky Plots: A Knee-point in the Plot for Passive Films on Chromium

Ren

Zhou

2017

J. Electrochem. Soc.

View full text Add to dashboard Cite

In previous studies, there has been no consensus on the semiconducting properties of passive films on pure chromium by either photo-electrochemical analysis or Mott-Schottky (MS) analysis. In this work, a knee-point (KP), which is an exotic phenomenon in MS plots for some passive films, was found to be independent of the oxidation of Cr 3+ to Cr 6+ . This shiftable KP was observed for the first time, and a strong correlation between the KP and the corresponding direct-current variation of the film during the MS test was also found. The investigation of the capacitance-time relationship on the aging of passive films provided a rational interpretation of the KP for the film investigated. These findings demonstrated that the film formed on Cr was not an ideal semiconductor, and MS analysis was not applicable to the film. Chromium is an element widely used in stainless steel alloys and nickel-based alloys because of its excellent corrosion resistance due to its highly stable passive film. It is well known that the passive film consists of an Cr 2 O 3 inner layer and an Cr(OH) 3 outer layer. 1Numerous studies on the electronic properties of passive films have been reported. Recently, however, both p-type 2,3 and n-type 4 films were observed using MS analysis.For MS plots, we note that there is a knee-point (KP) (Fig. 1) where the slope changes from positive to negative at a higher anodic potential for the passive film on Cr. A KP is not common for an ideal semiconductor. However, this feature also commonly appears in the MS plots of some thin passive films, including those on iron, 5,6 nickel, 7,8 stainless steels, 9-11 and Ni-Cr-Mo alloys. 12-14 The KP of passive Cr has been attributed to the film oxidation of Cr 3+ to Cr 6+ . 6,13,15 The generation of excess cation vacancies due to oxidation leads to p-type semiconductive behavior, while the film resistance decreases accordingly because of the thinning of the inner layer. 13 However, in our work on Cr, Inconel 625 and C2000 showed that the impedance did not decrease when the film formation potential (E F ) was higher than the KP potential (E KP ). Similar results have also been reported on Alloy 22 in chloride solutions.14 Additionally, the dependence of impedance on E F for the passive 316L SS in borate buffer 16 was not consistent with either n-type 17,18 or with mixed-type. (For example, MS plots presented an M-shape obtained by some authors.) 6,19,20 Recently, we observed that the KP for a film could shift in both the anodic and cathodic directions under varying test conditions. This raises question about the semiconducting property, because if the KP shifts to a negative potential direction, the plot presents a p-type character; otherwise, it presents an n-type character. In this paper, KPs in MS plots of passive films on Cr in 0.05 M H 2 SO 4 were studied in detail using conventional electrochemical methods: potentiostatic polarization, MS analysis, electrochemical impedance spectroscopy (EIS), and I-E fixed sampling. The new phenomenon observed was analyzed ...

show abstract

“…Em geral, há um consenso (Castle e Clayton, 1977, Ginesan e Smith, 1988, Hakiki et al, 1995, Bojinov et al, 1999, Martini e Muller, 2000, Montemor et al, 2000, Oh et al, 2004 sobre o caráter duplex dos filmes passivos sobre aços inoxidáveis. Estes filmes geralmente apresentam gradientes de composição química e podem ser constituídos de regiões com propriedades semicondutoras diferenciadas (Hakiki et al, 1995, Martini e Muller, 2000, Montemor et al, 2000.…”

Section: Resistência à Corrosão E Camada Passivaunclassified

“…Estes filmes geralmente apresentam gradientes de composição química e podem ser constituídos de regiões com propriedades semicondutoras diferenciadas (Hakiki et al, 1995, Martini e Muller, 2000, Montemor et al, 2000. Hakiki et al (1995) analisaram aços inoxidáveis 304 e 316 em uma solução de borato pelos diagramas de Mott-Schottky e concluíram que a película passiva era composta de duas camadas, uma interna rica em cromo e outra externa, rica em ferro.…”

Section: Resistência à Corrosão E Camada Passivaunclassified

Corrosão de aços inoxidáveis avançados em meios fisiológicos

Terada¹

View full text Add to dashboard Cite

were rich in chromium and iron. The electrochemical behavior of these steels was investigated using electrochemical impedance spectroscopy (EIE), potentiodynamic polarization, scanning vibrating electrode technique (SVET), field emission gun (FEG), scanning electrochemical microscopy (SECM), optical microscopy (OM) and scanning electron microscopy (SEM). The test electrolytes used were Hanks solution, a culture medium known as Minimum Essential Medium (MEM) and a buffered phoshated solution (PBS). The EIE results were interpreted using equivalent electrical circuits that simulated the duplex structure of the oxide layer. All the materials were more resistant to localized corrosion than AISI 316L, with composition similar to ASTM F-138 SS. The results also highlighted the effect of the solution annealing treatment on corrosion resistance of the high nitrogen DIN W. Nr. 1.4460.The DIN W. Nr. 1.4970 steel was cytotoxic. Hence it cannot be used as a biomaterial.The DIN W. Nr. 1.4575 steel and Incoloy MA 956 can only be used for applications of easy removal, such as for odontological prostheses, due to their ferromagnetic properties. The DIN W. Nr. 1.4460 (0.87% nitrogen) steel was the SS with the best properties, among those studied for use as biomaterials.

show abstract

Characterization of the film formed on iron in borate solution by electrochemical impedance spectroscopy

Cited by 148 publications

References 17 publications

Diffusivity of Point Defects in the Passive Film on Stainless Steel

Diffusivity of Point Defects in the Passive Film on Stainless Steel

Rediscovering Mott-Schottky Plots: A Knee-point in the Plot for Passive Films on Chromium

Corrosão de aços inoxidáveis avançados em meios fisiológicos

Contact Info

Product

Resources

About