Potentiodynamic polarisation curves and pitting descriptors of 316L stainless steel in NaCl electrolyte

This deposit contains all data and code supporting the analysis in: Identifying stable pitting pathways in 316L stainless steel via fractal-inspired PCA-based clustering Coelho L.B., Amand T., Torres D., Olivier M., Ustarroz J. (accepted 21 April 2025, npj Materials Degradation) Included files calculated_epit_data.csv – the ML-estimated critical pitting potentials (Epit) calculated_logipit_data.csv – the ML-estimated log(jₚᵢₜ) values corresponding to Epit calculated_epass_data.csv – the ML-estimated passive potentials (Epass) and log(jₚₐₛₛ) calculated_epit_df_meta_data.csv – manually curated Epit values just before stable pit growth calculated_logipit_df_meta_data.csv – manually curated log(jₚᵢₜ) values just before stable pit growth Critical-descriptor definitions The critical pitting potentials (Epit) and passive potentials (Epass) were estimated using the machine learning (ML) model described previously [1]. The files calculated_epit_df_meta_data.csv and calculated_logipit_df_meta_data.csv contain the last metastable-pitting descriptors—manually identified—immediately prior to the onset of stable pit growth. Experimental methods The macro-scale potentiodynamic polarization (PP) tests were performed at varying NaCl concentrations (0.005 M, 0.01 M and 0.05 M). Using an SP-300 (Bio-Logic) potentiostat inside a Faraday cage, the cell comprised: WE: 316L SS specimen (~1 cm² exposed area) RE: Ag/AgCl/KCl_sat inside a Luggin capillary CE: platinum foil After 60 min immersion to stabilize the open-circuit potential (OCP), polarization scans ran from –30 mV to +900 mV vs. OCP at 0.5 mV/s, matching our previous macro PP study on the same sample [2]. Each NaCl concentration was tested 28 times (84 curves total). References [1] L.B. Coelho, D. Torres, V. Vangrunderbeek, M. Bernal, G.M. Paldino, G. Bontempi, J. Ustarroz, Estimating pitting descriptors of 316 L stainless steel by machine learning and statistical analysis, Npj Mater Degrad 7 (2023) 82. https://doi.org/10.1038/s41529-023-00403-z. [2] L. B. Coelho, S. Kossman, A. Mejias, X. Noirfalise, A. Montagne, A. Van Gorp, M. Poorteman, M. G. Olivier, “Mechanical and corrosion characterization of industrially treated 316L stainless steel surfaces,” Surf. Coat. Technol. 382 (2020) 125175. https://doi.org/10.1016/j.surfcoat.2019.125175