Golpar leaves extract application for construction of an effective anti-corrosion film for superior mild-steel acidic-induced corrosion mitigation at different temperatures

Abstract

The application of bio-compatible organic compounds from Golpar leaves as a green source to establish a protective layer on the steel surface is the main target of this study. So herein, the effect of environmental-friendly and cost-effective Golpar leaves extract (GLE) on the corrosion retardation of the mild-steel (MS) substance in HCl aggressive solution (1 M) is reported. The Fourier transform infrared (FT-IR) and ultraviolet-visible (UV–vis) tests were conducted to recognize the GLE functional groups. The effect of GLE on the topology and morphology of the steel surface subjected to the GLE-HCl solution was investigated via atomic force microscopy (AFM) and field emission scanning electron microscopes (FE-SEM), respectively. Accordingly, the heterogeneity and roughness of the steel surface decreased in the presence of the GLE. The deposition of a graphene-like film that consists of GLE phytochemicals was examined by Raman spectroscopy ( I D / I G = 0.60). The grazing incidence X-Ray diffraction (GIXRD) indicated the formation of inhibitor and iron complex layers over the surface. The contact angle (CA) outcomes demonstrated 45° enhancement of the metal surface hydrophobicity in the presence of GLE. The electrochemical impedance spectroscopy (EIS), potentiodynamic polarization spectroscopy (PDS), and weight loss measurements were utilized to survey the steel plates' corrosion resistance. The total resistance of 6.8, 8.1, 9.2, and 9.8 KΩ cm 2 was obtained at the concentrations of 400, 600, 800, and 1000 ppm, respectively. The results revealed that in the presence of 1000 ppm GLE, the inhibition activity was improved to up 91% after 10 h at 25 °C. The inhibition efficiency of GLE-contained solutions remained 90% even at 35 and 45 °C during 10 h of exposure, which is a significant number in comparison with most of the reported green inhibitors. According to the weight loss determinations, 90% surface coverage was attained after 5 h immersion in 1000 ppm GLE. Moreover, obeying Langmuir-isotherm the GLE organic compounds adsorbed on the steel substance and showed mixed (anodic/cathodic) corrosion inhibition activity. • The effect of GLE concentration on the MS corrosion protection in hydrochloric acid aqueous (1 M) solution was studied. • Addition of 1000 ppm GLE to the acidic media caused 91% inhibition efficiency and 92% surface coverage after 10 h of immersion. • Deposition of a hydrophobic and graphene-like film that consists of GLE phytochemicals was examined by Raman spectroscopy. • GLE acted as a mixed inhibitor in the acidic media and suppressed the corrosion reaction obeying Langmuir-isotherm.