Pitting corrosion of stainless steels

Uhlig, H. H. and Gilman, 3. R., Inhibition of Pitting Corrosion of Stainless Steel 18/8 in Iron(III) Chloride Solutions by Nitrates , Z. Physik. Chem.,21/6, 127 (1964) C.A., 61,9231c Fisher, W. R., Pitting Corrosion, Especially of Titanium. 1 Corrosion Studies , Techn. Mill. 

Several methods to determine the resistance to pitting corrosion of stainless steel have been introduced. The methods are divided into two groups. The first group includes determination of pitting potential, CPT, in FeClj... 

It is well known that chloride ions in aqueous or humid systems promote pitting corrosion of stainless steel surfaces. 

In a different application, Williams and coworkers were interested in using the SECM to identify a precursor state to the pitting corrosion of stainless steel (12) and also to elucidate the mechanism by which a pit could be maintained and propagate further (13), once it had been initiated. For these studies, a commercial AFM (Quesant Resolver ) was adapted for use as an SECM. The tip electrode was a Pt-Ir wire electrolytically sharpened and insulated, as for electrochemical STM. A two-electrode mode was used with a Pt counterelectrode of much larger area than the stainless steel working electrode. The potential of the counterelectrode was standardized against an SCE. The probe UME was maintained at the same potential as the Pt counterelectrode. Typical tip-substrate separations of 0.1-0.5 /xm were employed for imaging purposes, with the distance carefully established by ap-... 

K. Osozawa, N. Okato, Y. Fukase, and K. Yokato, Effects of Alloying Elements on the Pitting Corrosion of Stainless Steel, Proceedings of the Fifth International Congress on Metallic Corrosion, National Association of Corrosion Engineers, 1974, p 270-274... 

B. Baroux, Further insights on the pitting corrosion of stainless steels, in P. Marcus (Ed.), Corrosion Mechanism in Theory and Practice, second ed., Marcel Dekker, New York, 2004. 

P.C. Pistorius, G.T. Burstein, Metastable pitting corrosion of stainless steel and the transition to sta-bdity, Philos. Trans. R. Soc. London A 341 (1992) 531—542. 

Williams, D.E., Westcott, C. and Fleischmann, M. (1985) Stochastic models of pitting corrosion of stainless steel part I. Modelling of the initiation and growth of pits at constant potential. Journal of The Electrochemical Society, 132, 1796. 

WUUams, D.E., Fleisehmann, M., Stewart, J. and Brooks, T. (1986) Some characteristics of the initiation phase of pitting corrosion of stainless steel. Materials Science Forum, 8, 151. 

A correct interpretation of the observed fluctuations requires an understanding of what processes are driving them. Generally speaking, for corrosion reactions this is not thermal fluctuations, so interpretation of the behavior in terms of Johnson noise in a simple resistor is not correct. The first approach to a rigorous analysis was made by Wilhams, Westcott and Fleischmann, in the case of the initiation of pitting corrosion of stainless steel [37-40]. 

Williams, D.E., Mohiuddin, T.F and Zhu, Y.Y. (1998) Elucidation of a trigger mechanism for pitting corrosion of stainless steels using submicron resolution scanning electrochemical and photoelectrochemical microscopy. Journal of the Electrochemical Society, 145, 2664— 2672. 

Wilhams, D. E., Westcott, C., and Fleischman, M., Stochastic Models of Pitting Corrosion of Stainless Steels, n. Measurement and Interpretation of Data at Constant PotentitJ, Journal of the Electrochemical Society, Vol. 132, No. 8,1985, pp. 1804-11. 

One must be careful about the corrosion allowance for pitting corrosion of stainless steel - there should not be one. This is because pitting corrosion is not a continuing phenomenon. When pitting corrosion happens, it happens over a short time which is not the situation envisioned by Equation 2.3. 

Lochkorrosion nichtrostender Stable (Pitting corrosion of stainless steels)... 

Corrosion inhibitors for steels are being continuously developed because of the ubiquitous use of steel in construction and its somewhat limited corrosion resistance, especially in the presence of water. A great number of papers are on the effect of corrosion inhibitors, and the overwhelming majority deals with the effect of inhibitors on uniform corrosion. Due to environmental restrictions on common inorganic inhibitors (Freedman, 1986), several studies suggest derivatives of some amino acids as corrosion inhibitors. A survey of a number of different organic compounds commonly used as uniform corrosion inhibitors showed that most compounds hardly affect the pitting corrosion of stainless steel however, one of... 

Further Insights on the Pitting Corrosion of Stainless Steels... 

Sulfate-reducing bacteria have also been reported to be responsible for pitting corrosion on stainless steels in aqueous environments. The mechanisms proposed are mostly related to iron and steel. However, a different mechanism has been proposed in which the role of thiosulfate in the microbial pitting of stainless steel has been emphasized [137]. The same authors have also demonstrated clearly that SRB-induced pitting corrosion of stainless steel is unlikely to occur in a uniformly anaerobic SRB medium, whereas it will occur when the anaerobic sites are coupled to an oxygen cathode [136]. 

Y. Y. Zhu and D. E. Williams, Scaiming electrochemical microscopic observation of a precursor state to pitting corrosion of stainless steel , J. Electrochem. Soc. 144, L43 (1997). 

Ilevbare, G. O., Burstein, G. T. 2003. The inhibition of pitting corrosion of stainless steels by chromate and molybdate ions. Corrosion Science, 45,1545-1569. 

Pitting corrosion can lead to unexpected catastrophic system failure. The spht tubing in Figure 2.17 was caused by pitting corrosion of stainless steel. 

Figure 2.17 Pitting corrosion of stainless steel. (Reproduced with permission from Analog Luis Orozco.)...

Qin, R.-J., M. Lu, W.-K. Guo, and L. Niu, Localized electrochemical scanning study on pitting corrosion of stainless steel in acidic chloride solutions, Eushi Kexue Yu Fanghu Jishu, 21, 2009, 230. 

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