Quantitative measurement of corrosion at the nanoscale by in situ spectral modulation interferometry

In situ quantitative topographic measurement and corrosion behaviour of low carbon steel in chloride solutions

“…The SMI technique offers sub-nanometre vertical precision, sub-micrometre lateral resolution, high-speed image acquisition (up to 120 Hz) and speckle-free phase imaging using a Linnik interferometer [54,57]. SMI uses a broadband light beam from a super-luminescent diode (SLD, Superlum; wavelength, λ = 837 nm, Δλ = 54 nm).…”

“…Similar to the previous study [54], a three-electrode cell was employed, with the sample coupon acting as the working electrode (WE). A saturated silver/silver chloride (Ag/ AgCl) electrode was the reference electrode (RE) with the tip set at 2 mm from the alloy surface of the WE, and stainless steel was used as the counter electrode (CE).…”

“…The details of the fluid cell are presented in Ref. [54], and the fluid cell schematic is shown in Figure 3.…”

Surface Characterization Techniques: A Systematic Review of their Principles, Applications, and Perspectives in Corrosion Studies

“…Other QPM and surface measurement techniques.-Aside from the well-researched AFM, VSI, and DHM techniques, there are other varieties of QPM and surface measuring systems, as shown in Table IV that would be relevant for discussion, including in situ scanning tunneling microscopy (STM), 119,[121][122][123] confocal laser scanning microscopy (CLSM), 114,[116][117][118] digital holography (DH) 102,104,105 digital speckle pattern interferometry (DSPI), [100][101][102] in situ special modulation interferometry (SMI) 124 and in situ light reflectivity microscopy, 125,126 etc. Interestingly, their working principles or mode of operation are quite similar to the three systems (AFM, VSI, and DHM) earlier discussed above.…”

“…131,132 Lastly, SMI was recently developed by Shang et al 133 for studying structures and dynamics of biological specimens but has now been recently adopted for in situ quantitative measurements of metallic corrosion at the nanoscale. 124 SMI combines spectraldomain low-coherence interferometry with spectral modulation technique and the schematic setup as well as its phase demodulation procedure is presented in Fig. 5.…”