Abstract

APERADOR, W.; BAUTISTA RUIZ, J. H.  and  PARDO CUERVO, O.. Electrochemical behavior of thin films of CrN/Cr obtained varying the bias potential. Rev. Mex. Ing. Quím [online]. 2012, vol.11, n.1, pp.145-154. ISSN 1665-2738.

In this article is presented the applicability of the Kramers-Kronig relations (KK) to the validity study of the impedance measurements (EIS) on the variation of bias potential of the CrN / Cr, depositing on AISI 4140 steel substrates by the method of DC reactive sputtering magnetron in contact with NaCl 0.5 M. Nyquist diagrams show a capacitive behavior with a high impedance module and two time constants. In the implementation of KK integrals, were used two procedures: one based on an equivalent circuit thaa meets the KK relations, and another, according to on ohmic resistor connected in parallel. Additionally, from Tafel polarization curves were validated the found results with EIS. The morphology of the coating was evaluated by scanning electron microscopy of high-resolution; the optical microscopy (OM) was used to determine the morphology after the electrochemical evaluation. The results of impedance as a function of bias potential of CrN / Cr deposited on AISI 4140 steel substrates satisfy the KK relations; also it was found a dependency ratio of polarization potential on corrosion rate.

Keywords : Kramers-Kronig; CrN/Cr; EIS; Tafel; equivalent circuit.

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