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Electrochemical Characterization of the Stainless Steel Corrosion immersed in Seawater under Turbulent Flow conditions by Electrochemical Noise D. Cabrera-de la Cruz1, R. Galván-Martínez1, R. Orozco-Cruz1, R. Torres-Sánchez2, A. Contreras3 1

Unidad Anticorrosión, Instituto de Ingeniería, Universidad Veracruzana, Av. S.S. Juan Pablo II S/N, Z. Universitaria, Fracc. Costa Verde, Veracruz, México, CP 94294. Email: [email protected]

2

Universidad Michoacana de San Nicolás de Hidalgo, Instituto de Investigaciones Metalúrgicas, Edif. “U”, C.U. Apartado Postal 52-B, C.P. 58000, Morelia, Mich. México. 3

Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas Norte #152, Col. San Bartolo Atepehuacan, México D.F. C.P. 07730, México.

ABSTRACT The electrochemical studies of the corrosion can provide indirect techniques that they can determinate the corrosion rate of metals or alloys immersed in a corrosive medium. For many years, most studies about the cathodic and anodic polarization behaviour of metals have been confined to traditional steady-state techniques, such as potentiodynamic sweep measurements. However, steady-state techniques are limited because they give information only on the ratedetermining step. Moreover, during the measuring process, technique such as potentiodynamic sweep polarize the electrode surface to such a great extent, in order to uncover corrosion mechanism, that the validity of the results can be questioned particularly in the cases when protective films. Transient electrochemical techniques such as Electrochemical Noise (EN), are less intrusive because they can provide information about the processes without disturbing the reactions with the voltage application. Keywords: Corrosion, Passivation, Steel, Optical Metallographic, Oxide. INTRODUCTION The study of electrochemical corrosion has some indirect techniques in order to determinate the corrosion rate of an alloy or metal, immersed in a corrosive medium. One of these techniques is the electrochemical noise measured (ENM). Electrochemical Noise (EN) consisted of potential and current fluctuations spontaneously generated by corrosion processes recorded as a function of time [1-4]. EN could be generated by charge transfer on surface of the metal, by the dissociation, reduction or oxidation reactions that it could be happen in the electrolyte-metal system, etc. Two popular procedures for the mathematical treatment of ENM data have been recently implemented, namely, the statistical method and spectral analysis method [5]. It is important to mention that the spectral analysis method (done in the frequency domain) include the power spectrum analysis and the electrochemical noise impedance [6]; whereas the statistical method include (done in the time domain) median, standard deviation, electrochemical noise resistance, pitting index or localization index, transients analysis, etc [5,7]. Electrochemical

Mater. Res. Soc. Symp. Proc. Vol. 1275 © Materials Research Society

Noise measurement can provide information about the processes without di