Title: Investigation of black cumin cake extract as a green corrosion inhibitor for 316L stainless steel: combined experimental and theoretical approaches

Authors: B. Maalem; S. Abderrahmane; S. Athmani; B. Bezzina; K. Moussaoui; K. Berrezag; D. Berdjane

Addresses: Surface Engineering Laboratory (LIS), Faculty of Sciences, Badji Mokhtar-Annaba University, P.O. Box 12, Annaba, 23000, Algeria; Research Center in Industrial Technologies (CRTI), P.O. Box 64, Chéraga 16014 Algiers, Algeria ' Surface Engineering Laboratory (LIS), Faculty of Sciences, Badji Mokhtar-Annaba University, P.O. Box 12, Annaba, 23000, Algeria ' Scientific and Technical Research Center in Physico-chemical Analysis (CRAPC), BP 384, Bou-Ismail Industrial Zone, RP 42004, Tipaza, Algeria ' Research Center in Industrial Technologies (CRTI), P.O. Box 64, Chéraga 16014 Algiers, Algeria ' Surface Engineering Laboratory (LIS), Faculty of Sciences, Badji Mokhtar-Annaba University, P.O. Box 12, Annaba, 23000, Algeria ' Surface Engineering Laboratory (LIS), Faculty of Sciences, Badji Mokhtar-Annaba University, P.O. Box 12, Annaba, 23000, Algeria ' Research Center in Industrial Technologies (CRTI), P.O. Box 64, Chéraga 16014 Algiers, Algeria

Abstract: In this study, black cumin cake extract (BCCE) was evaluated as a green corrosion inhibitor for 316L stainless steel in 3M HCl. The extract was obtained via maceration in 1M HCl and characterised using phytochemical screening, gas chromatography-mass spectrometry, FTIR and UV-visible spectroscopy. The inhibitory behaviour of BCCE was assessed through electrochemical impedance spectroscopy and potentiodynamic polarisation. SEM-EDX and profilometry were used to examine the surface topography. The inhibitive efficiency reached 84.4% at 20.10^-2 v/v. The ΔG_ads was found -19.19 kJ.mol^-1 at 298 K indicating that the adsorption acts as a physisorption inhibitor. Adsorption of BCCE on 316L surface obeyed the Langmuir adsorption model. SEM-EDX and profilometry micrographs confirmed the formation of an inhibitory film. Computational methods, including density functional theory and Monte Carlo simulation, were carried out to investigate the adsorption characteristics and inhibition mechanism of the molecules present in BCCE. These theoretical approaches supported and interpreted the experimental findings.

Keywords: black cumin cake; corrosion; eco-friendly inhibitor; 316L; EIS; DFT; GC-MS.

DOI: 10.1504/IJSURFSE.2026.154837

International Journal of Surface Science and Engineering, 2026 Vol.20 No.2, pp.155 - 188

Received: 16 Apr 2025
Accepted: 30 Oct 2025
Published online: 15 Jul 2026 *

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