INVESTIGADORES
VALCARCE Maria beatriz
artículos
Título:
Characterization of surface films on constructional steel in carbonated media containing chloride and nitrite ions
Autor/es:
M.A. FRONTINI; A. GÓMEZ SÁNCHEZ; G. GUIDONI; M. VAZQUEZ; M.B. VALCARCE; M.B. VALCARCE
Revista:
ELECTROCHIMICA ACTA
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2020 vol. 364
ISSN:
0013-4686
Resumen:
The inhibition effect of the NaNO2 on the electronic properties of the passive film wasinvestigated for carbon steel exposed in solutions of pH = 13 and pH = 9 keeping the ratio[inhibitor]/[chloride]=1. Cyclic voltammograms, polarization curves, electrochemicalimpedance spectroscopy, Mott-Schottky plots and X-ray photoelectron spectra wereanalyzed. Steel is passive at pH=13 and active at pH=9 (carbonated solutions). Passivitycan be regained in carbonated solutions when nitrite ions are also present. The thicknessand composition of the surface films depend on alkalinity. Both films behave as n-typesemiconductors. Donor density values are similar for films grown in solutions containingnitrite ions, regardless of the presence of carbonate ions and the difference in alkalinity.Nitrite ions inhibit pitting in both solutions, although the difference between the pittingand the open circuit potential is 2.7 times higher at pH=13. Donor density values cannotbe used as the only parameter to evaluate pitting risk.