An in situ optical second harmonic generation study of carbon steel in contact with an alkaline aqueous solution containing glutamic acid

Abstract

In this paper we report a spectroelectrochemical investigationrelevant to the elucidation of rebar corrosion processes-based on in situ optical second-harmonic generation spectroscopy. We studied the corrosion behaviour of a carbon steel electrode in contact with an alkaline aqueous solution-simulating the electrolyte of freshly prepared cement paste-containing glutamic acid, a candidate corrosion inhibitor [1]. The non-linear time-dependent optical response to exciting radiation at 1064 nm has been recorded as a function of applied potential. This approach allows to obtain detailed information regarding the dynamic electronic structure of the corrosion interface, which is not available from other electrochemical or spectroelectrochemical approaches.

Second‐harmonic generation technique for in situ study of passive film formation on carbon steel surfaces in aqueous solutions

“…In this regard, SHG has been used to study the effectiveness of corrosion inhibitors on mild steel. [24,[36][37][38][39] A third advantage of using SHG against other spectroscopic techniques concerns the possibility to characterize the oxides formed on the surface. Very few studies are available in the literature concerning the use of SHG on carbon steel or iron.…”

“…Very few studies are available in the literature concerning the use of SHG on carbon steel or iron. [13,14,24,36,38,39] To our knowledge, the only studies related to the different responses in SHG susceptibility on iron passivation in alkaline media were given in the late 1980s by Biwer et al [13,14] In these studies, Biwer et al studied passive film formation on iron samples with SHG. Biwer et al, by coupling cyclic voltammetry with SHG, studied the oxidation and reduction of passive film on iron samples in alkaline electrolytes, namely, 0.1 M NaOH and borate buffer (pH approximately 8.5).…”

“…Studying the formation of passive film on metals with spectroscopic and microscopic techniques has a long tradition. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] For the case of iron or carbon steel passivation and passive film composition, x-ray photoelectron spectroscopy, [3,4,[18][19][20][21] Raman spectroscopy, [10,11,15,16,22,23] x-ray absorption near edge structure, [8] light reflectance technique, [1,7,12] second-harmonic generation (SHG), [13,14,24] and other spectroscopic techniques [2,5,6] have been applied. These techniques differ in terms of in situ applicability, accessibility of measurement instrumentation, need for sample preparation, and spatial and temporal resolution.…”

“…In this regard, SHG has been used to study the effectiveness of corrosion inhibitors on mild steel. [ 24,36–39 ]…”