Silicate Ions as Corrosion Inhibitors for Construction Steel in Chloride-Contaminated Environments

F. MONTES; M.A. FRONTINI; M. VÁZQUEZ; M.B. VALCARCE

CORROSION

NATL ASSOC CORROSION ENG

Año: 2020 vol. 76 p. 1147 - 1154

0010-9312

Silicate ions were tested as corrosion inhibitors for construction steel using concrete pore simulating solutions contaminated with chloride ions.The results are compared to those from solutions with no silicate and with no silicate and no chloride ions. The evaluation included typicalelectrochemical techniques such as cyclic voltammetry, polarization curves, and weight loss evaluation after a 60-day immersion. Surface analysiswas undertaken using micro-Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Polarization curves show no sign of pitting and lowcorrosion current densities if silicate ions are present, even when chloride ions are also in the system. In parallel, no localized attack is observedafter 60 days of immersion in solutions containing an Inhibitor/Chloride = 1 ratio. Cyclic voltammograms and XPS spectra indicate that the presenceof silicate ions affects the composition and thickness of the passive film: the film becomes thinner and contains more Fe(II) species. All the resultsshow that silicate ions act as promising inhibiting agents.