BEHAVIOR OF CARBON-STEEL IN COMPLEXING ENVIRONMENT AT DIFFERENT TEMPERATURES STUDIED BY ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY

In this paper, the behaviour of carbon steel in 6% Ammonium salt of Et hylenediaminetetraacetic acid dissolution (pH = 9) has been studied at temperatures between 25 and 85 degrees C, with potentiodynamic scans and electrochemical impedance spectra at different points of polarizat ion curves. On these curves, a reduction of the passive zone is observ ed when the temperature is increased. When the electrochemical impedan ce spectra on points of the passive zone are realized, it is observed that the nature of the film does not change in an important way with t emperature variations. Likewise, passive films of Fe3O4 have been obta ined with the polarization of carbon steel coupons at the middle of th e activation zone until the current density decreased from mA/cm(2) to mu A/cm(2), and these films have been characterized with electrochemi cal impedance spectroscopy.