Electrochemical characterization of a Fe-based shape memory alloy in an alkaline medium and the behaviour in aggressive conditions
DATE:
2023-03
UNIVERSAL IDENTIFIER: http://hdl.handle.net/11093/4482
EDITED VERSION: https://linkinghub.elsevier.com/retrieve/pii/S0013468623002219
DOCUMENT TYPE: article
ABSTRACT
A Fe-17Mn-6Si-19Cr-4Ni-1(V,C) shape memory steel (SMS) was characterised electrochemically in its unstrained
and pre-strained conditions. The work focused on analysing the passive films generated in alkaline conditions,
and on the behaviour of those passive samples in various Cl /OH ratios. The passive films were developed by
cyclic voltammetry and their characterisation was performed by electrochemical impedance spectroscopy (EIS)
and X-ray photoelectron spectroscopy (XPS); these tests were also carried out in 304 L stainless steel specimens
for comparison purposes. The results indicated that the film characteristics (thickness and composition) were
similar in all the samples, although higher corrosion resistance was observed in the 304 L due to the higher Cr
content. In addition, the behaviour of the passive samples in aggressive conditions was assessed by potentiodynamic
measurements. The results stated that the shape memory steels were more sensitive than the stainless
steel to the aggressive conditions, especially when the alloy was pre-strained. It was also observed that the SMS
exhibited a characteristic corrosion morphology localized at the grain boundaries