TY - JOUR AU - Bautista, A. AU - Blanco, G. AU - Velasco, F. AU - Gutiérrez, A. AU - Palacín, S. AU - Soriano, L. AU - Takenouti, H. PY - 2007/12/30 Y2 - 2024/03/29 TI - Passivation of duplex stainless steel in solutions simulating chloride-contaminated concrete JF - Materiales de Construcción JA - Mater. constr. VL - 57 IS - 288 SE - Research Articles DO - 10.3989/mc.2007.v57.i288.62 UR - https://materconstrucc.revistas.csic.es/index.php/materconstrucc/article/view/62 SP - 17-32 AB - Most studies published to date on the corrosion behaviour of stainless reinforcing steel are based on austenitic steel. The market presence of corrugated duplex steel is growing, however. The present study compared passivity in 2205 type duplex and 304 type austenitic stainless steel. Polarization tests in chloride-containing Ca(OH)<sub>2</sub> solutions confirmed the exceptional performance of duplex steels. X-ray photoelectronic spectroscopy (XPS) showed that the passive layer generated on duplex stainless steel in media simulating concrete pore solutions had a higher Cr content than the layer formed on steel in contact with the air. The XPS results also revealed that in duplex steel the form adopted by the passive layer Fe oxides was Fe<sub>3</sub>O<sub>4</sub> in the solutions simulating concrete, rather than Fe<sub>2</sub>O<sub>3</sub>, as in duplex steel exposed to air. Electrochemical impedance spectroscopy (EIS) can be used to monitor the transformations taking place in the passive layer and analyze the factors involved. ER -