Abstract

RINCON ORTIZ, Mauricio; RODRIGUEZ, Martín Alejandro  and  CARRANZA, Ricardo Mario. Effect of carbonate chemical speciation on crevice corrosion of nickel superalloy. Rev. ion [online]. 2017, vol.30, n.1, pp.7-19. ISSN 0120-100X.  https://doi.org/10.18273/revion.v30n1-2017001.

The inhibitory effects of carbonate chemical species on the susceptibility of crevice corrosion of the alloy 22 in chloride solutions were studied. In this work electrochemical techniques such as Anodic Polarizations Curves and Potentiodynamic-Galvanostatic-Potentiodynamic (PD-GS-PD), Electrochemical Impedance Spectroscopy and Scanning Electron Microscopy (SEM) were applied to determine the passive behavior of the alloy in the presence of these species. Results indicated that carbonic acid and bicarbonate not showed inhibitory effects on the conditions studied. Carbonate presented a critical molar ratio independent of the chloride concentration. The presence of an anodic peak was found, related with carbonate concentration. The corrosion rate obtained were less than 0.4μm/year at 24h of immersion.

Keywords : Alloy 22; Crevice corrosion; carbonate chemical speciation; cloruros; repassivation potential; PD-GS-PD.

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