Micro-scale potentiodynamic polarisation curves of 316L stainless steel

This database comprises 5 Potentiodynamic Polarisation (PP) datasets. Each dataset consists of a pair of CSVs: 1 file containing the values of the applied potential scan rate (mV/s); and 1 having the corresponding current density j (µA/cm²) values.

This database was first deployed in the following scientific article, accepted for publication in Corrosion Science journal on 10 March 2023:
"Probing the randomness of the local current distributions of 316L stainless steel corrosion in NaCl solution".
Leonardo Bertolucci Coelho1,2,∗, Daniel Torres1, Miguel Bernal1, Gian Marco Paldino3, Gianluca Bontempi3, Jon Ustarroz 1,2
1 ChemSIN – Chemistry of Surfaces, Interfaces and Nanomaterials, Université libre de Bruxelles (ULB), Brussels, Belgium
2 Research Group Electrochemical and Surface Engineering (SURF), Vrije Universiteit Brussel, Brussels, Belgium
3 Machine Learning Group (MLG), Université libre de Bruxelles (ULB), Brussels, Belgium
*[e-mail]

955 PP curves were recorded on the same 316L sample using the Scanning Electrochemical Cell Microscopy (SECCM) in hopping-mode protocol. A total of 12 SECCM sessions were performed, comprising maps with up to 17x17 points (during up to 24 h of continuous measurement).
Five different combinations of [NaCl] and voltammetric scan rates were employed: 0.005 M NaCl – 100 mV/s, 0.01 M NaCl – 100 mV/s, 0.01 M NaCl – 50 mV/s, 0.05 M NaCl – 100 mV/s, 0.05 M NaCl – 50 mV/s. The number of data samples (j Vs E curves) is 287, 377, 119, 125 and 47 for each dataset. These quantities of curves were considered representative of each testing condition, as the underlying j distributions were continuous.
The datasets were sliced from 0.5 V Vs Ag/AgCl (considerably more positive than the OCP) upward to avoid the eventual and deleterious occurrence of negative currents. Positive j values were preferred for building histograms and obtaining defined log(j) numbers.
The SECCM experiments were designed to detect low corrosion currents, and the trade-off for such a high signal sensitivity was the I saturation level at 10 nA. In case of missing data points in the anodic sweep data (most often caused by oversaturation at high applied overpotentials), these were replaced by data interpolation (Python pandas interpolate() method, spline). This data-filling procedure was used for a small proportion of the data populations (0%, 0%, 1%, 1% and 11%, respectively, for the datasets with increasing testing aggressiveness). The final shapes of the j Vs E curves were validated against similar curves with unsaturated signals at the relevant E ranges.