AMBALI IBRAHIM OWOLABISHUAIB-BABATAAJAO K.SBUSARI Y.ONURUDEEN T.AOKOLO J.ALONGE J.A2026-05-122026-05-122026-04-17Shuaib-babata,Y. L., Ajao, K. S., Busari, Y.O., Ambali, I. O., Nurudeen T. A., Okolo, J. A., & Longe, G.A3092-9385https://uilspace.unilorin.edu.ng/handle/123456789/18366The development of sustainable corrosion inhibitors for mild steel in acidic environments remains a significant challenge. This study evaluates the individual and synergistic inhibition performance of Parkia biglobosa peel extract (PBPE) and Delonix regia pod extract (DRPE) in 1.0 M HCl using weight loss, gasometric, electrochemical polarization, and electrochemical impedance spectroscopy (EIS) techniques. Results from mass loss and gasometric measurements reveal that PBPE accelerates corrosion, whereas DRPE exhibits high inhibition efficiency. Hybrid formulations (PBPE:DRPE = 3:1, 1:3, 2:1, 1:2, 1:1) demonstrate enhanced performance, with DRPE-rich systems (1:3 and 1:2) showing superior inhibition efficiency. Polarization studies indicate mixed-type inhibition behaviour, while EIS results show increased charge transfer resistance and reduced double layer capacitance with increasing inhibitor concentration, confirming adsorption-driven protective film formation. This work uniquely identifies the antagonistic behaviour of PBPE and the dominant inhibitory effect of DRPE, and demonstrates that optimized hybridization significantly improves corrosion resistance. The findings provide a novel approach for designing efficient, eco-friendly inhibitor systems through strategic combination of plant extracts.enCorrosionHydrochloric AcidInhibitorPlant extractsPotentialArticle