The effect of oxygen and biofilms on crevice corrosion of UNS S31803 and UNS N08825 in seawater was studied. Passivity breakdown occurred through crevice corrosion in UNS N08825 and through transpassive dissolution in UNS S31803 although both alloys displayed crevice corrosion under potentiodynamic conditions. The most severe crevice corrosion occurred in the absence of oxygen and the presence of a biofilm. Microbial adhesion as investigated by fluorescence microscopy occurred mainly outside the crevice and DNA sequencing revealed a shift in biofilm composition as a function of substratum surface and oxygen pressure.

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Pitting And Crevice Corrosion

Microbiologically influenced corrosion of common alloys used for subsea applications

Light microscopy, scanning electron microscopy and energy dispersive X-ray analysis were employed to identify the key factors responsible for the crevice-galvanic corrosion of shower curtain poles produced from EN AW-6060 alloy. The corrosion process has started between the aluminium poles and the metallized plastic hooks used to hang the shower curtains on the poles. The highly alkaline bathroom cleaning agent has penetrated between the aluminium profile and the plastic hooks leading to the dissolution of the unusually thin anodic oxide layer. The aluminium profile which has been stripped of its anodic oxide locally via crevice corrosion is then allowed to contact the Ni-, Cr- and Cubearing coating of the plastic hooks. The corrosion process has accelerated due to a galvanic couple effect as evidenced by the analysis of the corroded regions where Cu and Ni were abundant.

Crevice-Galvanic Corrosion in Aluminium Shower Curtain Poles

Effect of Temperature on the Repassivation Kinetics of Crevice-Corroded Nickel Base Alloys

The objective of this work is to achieve an analyti cal predictive model to study the influence of surface topography on the corrosion re sistance of UNS S31600 stainless steel, in a solution of sodium chloride NaCl, at 6% by weight as electrolyte, applying the finite element method. The surface topography was given by the average roughness variation of a UNS S31600 work piece in superfinish turning, of which correlation with the corrosion resistance was examined. The analytic l results show that corrosion physico-chemical parameters, polarization resistanc e, corrosion rate, corrosion potential, and current density have a very remarkable correlat ion with the surface roughness obtained by the superfinish turning. This is due to a very significant affinity between the plastic deformation depth obtained by turning, and the pits development on the work piece surface. The whole work was completed by an empirical analys is, in order to validate the analytical results obtained in comparison with the experimental results.

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Tetrahedral Finite Element Modeling of UNS S31600 Stainless Steel Corrosion Behavior under Superfinish Turning Conditions

Localized corrosion is a precursor to the deterioration of carbon steel reinforcing bars in concrete. The localized corrosion of carbon steel in simulated concrete pore solutions was investigated by cyclic potentiodynamic polarization (CPP) technique. A four-factor, two-level, full factorial design and a five-factor, two-level, Plackett-Burman design were used to study the effects of OH−, Cl−, , , with Na+ and Ca2+ cations on the localized corrosion of carbon steel. The results show that the occurrence of localized corrosion can be evaluated by the type of CPP curves (negative, mixed, or positive hysteresis) and the difference between the open-circuit and repassivation potentials (OCP-Erp). The lowest (OCP-Erp), indicating a low risk of pitting corrosion, could be obtained with high OH−, high , and low Cl−, whereas the effect of was not significant. The corrosion activities near the OCP were measured using linear polarization resistance and electrochemical impedance spectroscopy methods. They indicated that NO2− and Cl− were the main factors influencing the corrosion rate. The cationic species did not have a significant influence on the electrochemical parameters.

Pitting And Crevice Corrosion

Citations

Microbiologically influenced corrosion of common alloys used for subsea applications

Crevice-Galvanic Corrosion in Aluminium Shower Curtain Poles

Effect of Temperature on the Repassivation Kinetics of Crevice-Corroded Nickel Base Alloys

Tetrahedral Finite Element Modeling of UNS S31600 Stainless Steel Corrosion Behavior under Superfinish Turning Conditions

The Effects of Chloride, Nitrate, and Nitrite on the Localized Corrosion of Carbon Steel in Simulated Concrete Pore Solutions

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