Investigating the kinetics of layer development during the color etching of low-carbon steel with in-situ spectroscopic ellipsometry

József Bálint Renkó; Alekszej Romanenko; Tamás Bíró; Péter János Szabó; Péter Petrik; Attila Bonyár

doi:10.1016/j.heliyon.2024.e25271

Investigating the kinetics of layer development during the color etching of low-carbon steel with in-situ spectroscopic ellipsometry

Heliyon. 2024 Jan 27;10(3):e25271. doi: 10.1016/j.heliyon.2024.e25271. eCollection 2024 Feb 15.

Authors

József Bálint Renkó¹, Alekszej Romanenko^{2

3}, Tamás Bíró¹, Péter János Szabó¹, Péter Petrik^{2

4}, Attila Bonyár⁵

Affiliations

¹ Department of Materials Science and Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, H-1111, Budapest, Bertalan Lajos street 7, Hungary.
² Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly Thege Str. 29-33, 1121, Budapest, Hungary.
³ Doctoral School of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117, Budapest, Hungary.
⁴ Department of Electrical Engineering, Institute of Physics, Faculty of Science and Technology, University of Debrecen, 4032, Debrecen, Hungary.
⁵ Department of Electronics Technology, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, H-1111, Budapest, Egry József street 18, Hungary.

Abstract

Color etching is a useful corrosive process, widely applied in metallography to study the microstructure of metals. To prove the existence of the previously hypothesized steady-state etching rate, in-situ investigations were performed with spectroscopic ellipsometry during the color etching of ferritic materials. Kinetic information regarding the refractive index, extinction coefficient, and layer thickness were used to calculate the steady-state layer buildup rate, which was 1.90 ± 0.15 nm/s for low-carbon steel and 0.99 ± 0.06 nm/s for cast iron owing to its better corrosion resistance. The presented methodology and findings could help understanding other processes that involve the development of layers on metallic surfaces.

Keywords: Beraha˗I; Color etching; In-situ; Layer development kinetics; Optical microscopy; Spectroscopic ellipsometry.