Influence of chloride ion concentration on the corrosion behavior of Al-bearing TRIP steels
F. El-Taib Heakal; Noura Saad tantawy; O.S.Shehata;
Abstract
The effect of a systematic increase of chloride ion concentration on the electrochemical corrosion behavior
of two types of Al-bearing TRIP steels (T1 and T2) was studied in aqueous NaCl solutions. Several
electrochemical techniques were used comprising open circuit potential measurements, potentiodynamic
polarization curves and electrochemical impedance spectroscopy (EIS). Chloride concentration
has a critical influence on the corrosion rate of the two tested steel samples. For both steels the corrosion
rate first increased with increasing chloride content up to a certain critical concentration (CC), and then
decreased in solution with chloride level higher than the threshold value. TRIP steel T1 microalloyed with
Nb and Cr as compared to steel T2 not containing these two elements, exhibited lower corrosion rate and
smaller CC value, indicating better corrosion resistance to chloride attack, albeit the Al content in T2 is
220 times higher than that in T1. This is because Nb alloyed with TRIP steel likely enhances the formation
on the surface of a stable rust layer enriched with other passivating elements Al, Cu, Cr and Ni, which
has higher corrosion resistance and hence improve greatly the passive performance of the TRIP sample.
The ac impedance data are in good agreement with the OCP and dc polarization measurements. Surface
examinations via scanning electron microscope confirmed well the obtained results.
of two types of Al-bearing TRIP steels (T1 and T2) was studied in aqueous NaCl solutions. Several
electrochemical techniques were used comprising open circuit potential measurements, potentiodynamic
polarization curves and electrochemical impedance spectroscopy (EIS). Chloride concentration
has a critical influence on the corrosion rate of the two tested steel samples. For both steels the corrosion
rate first increased with increasing chloride content up to a certain critical concentration (CC), and then
decreased in solution with chloride level higher than the threshold value. TRIP steel T1 microalloyed with
Nb and Cr as compared to steel T2 not containing these two elements, exhibited lower corrosion rate and
smaller CC value, indicating better corrosion resistance to chloride attack, albeit the Al content in T2 is
220 times higher than that in T1. This is because Nb alloyed with TRIP steel likely enhances the formation
on the surface of a stable rust layer enriched with other passivating elements Al, Cu, Cr and Ni, which
has higher corrosion resistance and hence improve greatly the passive performance of the TRIP sample.
The ac impedance data are in good agreement with the OCP and dc polarization measurements. Surface
examinations via scanning electron microscope confirmed well the obtained results.
Other data
Title | Influence of chloride ion concentration on the corrosion behavior of Al-bearing TRIP steels | Authors | F. El-Taib Heakal; Noura Saad tantawy ; O.S.Shehata | Keywords | Alloys;Corrosion;Electrochemical techniques | Issue Date | 22-Jul-2011 | Publisher | Elsevier Ltd. | Journal | Materials Chemistry and Physics | Volume | 130 | Start page | 743 | End page | 749 | DOI | 10.1016/j.matchemphys.2011.07.064 |
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