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J.r. Galvele - One of the best experts on this subject based on the ideXlab platform.

Guoan Zhang - One of the best experts on this subject based on the ideXlab platform.

J Y Huang - One of the best experts on this subject based on the ideXlab platform.

Raul B. Rebak - One of the best experts on this subject based on the ideXlab platform.

  • Crevice Corrosion kinetics of nickel alloys bearing chromium and molybdenum
    Electrochimica Acta, 2012
    Co-Authors: Natalia S. Zadorozne, C M Giordano, Martín A. Rodríguez, Ricardo M. Carranza, Raul B. Rebak
    Abstract:

    Abstract The Crevice Corrosion kinetics of alloys C-22, C-22HS and HYBRID-BC1 was studied in several chloride solutions at 90 °C. The Crevice Corrosion resistance of the alloys increased with PREN (Pitting Resistance Equivalent Number), which is mainly affected by the Mo content in the alloys. The Crevice Corrosion kinetics of the three alloys was analyzed at potentials slightly higher than the repassivation potential. Crevice propagation was controlled by ohmic drop in the more dilute chloride solutions, and by charge transfer in the more concentrated chloride solutions. Ohmic drop was not a necessary condition for Crevice Corrosion to occur.

  • Efficiency of inhibitors for chloride-induced Crevice Corrosion of Alloy 22
    MRS Proceedings, 2012
    Co-Authors: Mauricio Rincón Ortíz, Martín A. Rodríguez, Ricardo M. Carranza, Raul B. Rebak
    Abstract:

    Alloy 22 is considered as a candidate for engineered barriers of nuclear repositories. Chloride is the only species present in groundwater that is able to promote Crevice Corrosion, if severe conditions such as high temperatures and a tight Crevice are present. Other species present in groundwater have been shown to be inhibitors or non-detrimental species. The objective of this work was to evaluate the efficiency of different species potentially found in groundwaters as possible inhibitors of Crevice Corrosion of Alloy 22. The Crevice Corrosion repassivation potential of Alloy 22 was determined in chloride plus inhibitor solutions at 90oC. The species tested as inhibitors were nitrate, sulfate, carbonate, bicarbonate, chromate, molybdate and tungstate. Nitrate was the most efficient among tested inhibitors. The carbonate was the only species of the carbonate / bicarbonate / carbonic acid equilibrium able to inhibit the chloride-induced Crevice Corrosion of Alloy 22. Sulfate, chromate and molybdate were moderately good inhibitors.

  • Anionic and Cationic Effects on the Crevice Corrosion Susceptibility of Alloy 22
    MRS Proceedings, 2011
    Co-Authors: Ricardo M. Carranza, Raul B. Rebak
    Abstract:

    AbstractAlloy 22 is highly resistant to all forms of Corrosion; however, it may suffer Crevice Corrosion in presence of chloride ions especially at temperatures higher than ambient and at anodic potentials. The susceptibility of Alloy 22 to suffer Crevice Corrosion is highly dependent on the type of electrolyte solution that is in contact with the alloy including variety of species in solution and their relative concentration. Laboratory research has shown that at a constant chloride concentration, the susceptibility of Alloy 22 to Crevice Corrosion is not influenced by the nature of the cations present in solution. On the other hand, that nature of the anions is highly influential. Of the anions present in ground water, only chloride is detrimental and the others are inhibitors or innocuous for Crevice Corrosion susceptibility. That is, the presence of the other anions counter balances the negative effect of chloride. The inhibition effect is explained and the likelihood that Alloy 22 would suffer Crevice Corrosion in contact with ground water is discussed.

  • Stifling of Crevice Corrosion in Alloy 22 During Constant Potential Tests
    Journal of Pressure Vessel Technology-transactions of The Asme, 2008
    Co-Authors: Raul B. Rebak
    Abstract:

    Artificially Creviced Alloy 22 (N06022) may be susceptible to Crevice Corrosion in the presence of high-chloride aqueous solutions, especially at higher temperatures and at anodic potentials. The presence of oxyanions in the electrolyte, particularly nitrate, inhibits the nucleation and growth of Crevice Corrosion. The current results show that Crevice Corrosion will develop in Alloy 22 when a constant potential above the Crevice repassivation potential is applied to a Creviced specimen. The analyses of the current output showed the presence of three characteristic domains: (1) passivation or induction time, (2) nucleation and growth, and (3) stifling and arrest. That is, under the tested conditions, Crevice Corrosion did initiate but after it reached a critical stage of growth, further damage stalled and the output anodic current returned to the passive values before the nucleation of the attack.

  • Environmental and Geometrical Conditions to Sustain Crevice Corrosion in Alloy 22
    2006
    Co-Authors: Ricardo M. Carranza, M A Rodr Guez, Raul B. Rebak
    Abstract:

    Alloy 22 (N06022) is highly resistant to localized Corrosion. Under aggressive environmental conditions Alloy 22 may be susceptible to Crevice Corrosion in hot chloride (Cl{sup -}) solutions. The objective of the present work was to explore the environmental and geometrical conditions for Crevice Corrosion to occur. Electrochemical tests were performed using PCA and prismatic mill annealed Alloy 22 specimens in chloride solutions. Crevice Corrosion current density was found to be a function of applied potential. i{sub CREV} values ranged from 40 {micro}A/cm{sup 2} to 20 mA/cm{sup 2}. Such low values of current density explained the absence of pitting Corrosion in Alloy 22 at any potential. Decreasing of the effective diffusion distance in a propagating Crevice is thought to cause Crevice Corrosion stifling or repassivation after long anodic polarization. Crevice Corrosion breakdown potential is expected to decrease with potential scan rate, approaching repassivation potential for low scan rates. The lowest Corrosion potential of Alloy 22 in hydrochloric acid solutions at which active Corrosion exists was proposed as the lowest possible repassivation potential for Crevice Corrosion.

Qian Hu - One of the best experts on this subject based on the ideXlab platform.

  • Crevice Corrosion Behaviors of X52 Carbon Steel in Chloride Containing Solutions
    Advanced Materials Research, 2013
    Co-Authors: Qian Hu, Jie Zhang, Feng Huang
    Abstract:

    The Crevice Corrosion behaviors of X52 carbon steel in two typical Cl--containing solutions were investigated by electrochemical noise and electrochemical impedance spectroscopy. Results show that oxygen concentration difference leads to the coupled current in NaCl + NaHCO3 solution while HAc concentration difference causes the coupled current in NaCl solution saturated with CO2 in the presence of HAc. There exists an apparent incubation stage during the Crevice Corrosion process of X52 carbon steel in the former. However, no obvious incubation period of Crevice Corrosion can be observed in the latter. Micrography shows that the Crevice Corrosion occurs indeed and the Corrosion inside the Crevice is not uniform.

  • the Crevice Corrosion behaviour of stainless steel in sodium chloride solution
    Corrosion Science, 2011
    Co-Authors: Qian Hu, Guoan Zhang
    Abstract:

    Abstract The Crevice Corrosion behaviour of 13Cr stainless steel in NaCl solution was investigated mainly by electrochemical noise measurements, considering the influences of the Crevice opening dimension ( a ) and the area ratio of the electrode outside the Crevice to the one inside the Crevice ( r ). Results show that the increase of r value prolongs the incubation period of Crevice Corrosion, but Crevice Corrosion develops rapidly once the Crevice Corrosion occurs. The Crevice Corrosion develops preferentially at the Crevice bottom and then spreads to the whole electrode surface. Proton could reduce on the uncorroded area and hydrogen bubbles form inside the Crevice.