Use of XPS for quantitative evaluation of tensile-stress-induced degradation of passive film on carbon steel in simulated concrete pore solution

摘要

In this paper, the tensile-stress-induced degradation of passive film on carbon steel is studied by means of X-ray photoelectron spectroscopy (XPS). A novel concept of shedding ratio is proposed to quantitatively characterize the degradation degree of passive film. The computational model of shedding ratio is derived on the basis of XPS reanalysis. Electrochemical tests are conducted on the carbon steel in both holding stress conditions and removed stress conditions to demonstrate the shedding-ratio model. Results show that the shedding ratio remarkably increases with the applied tensile stress, which is consistent with the rule obtained from the electrochemical tests. From electrochemical point of view, we derive that the shedding ratio has an inversely proportional relationship with the polarization resistance, which is also confirmed by the test results. Plus, it is also found that the degradation of the passive film can be partially recovered after the applied stress is removed. Generally, the shedding-ratio model on the basis of XPS reanalysis is physically meaningful and effective in the quantitative characterization of degradation level of passive film, which is worthy to be further investigated. (C) 2020 Elsevier Ltd. All rights reserved.