Electrochemical and microstructural analysis of azomethine polyamides as inhibitor for rebar corrosion under chloride contaminated pore solution

Abstract

The present study deals with the synthesis of two structurally different azomethine polyamides and their effect as inhibitor for a steel rebar in chloride containing pore solution. The amorphous and crystalline natures of the polymers were evaluated based on the XRD analysis. Potentiodynamic polarisation and impedance spectroscopy were employed to investigate the inhibition efficiency of the polymers for the protection of the rebar during corrosion. Scanning electron microscopic and atomic force microscopic techniques were used for the surface characterization of the steel in presence of the adsorbed layer formed by the polymer molecule leading to the inhibition from corrosion. The adsorption of the polyamide inhibitors on the steel rebar obeyed Langmuir adsorption isotherm. Two polyamide inhibitors showed similar inhibition efficiency at concentration ranging from 10 to 1000 ppm and maximum efficiency of 99.62% was achieved by the polymer PAMA1. Formation of protective layer on the surface of steel rebar by the inhibitors was attributed to be the reason for corrosion protection under chloride contaminated pore solution.

Investigation of Corrosion Inhibition of Mild Steel in 0.5 M H2SO4 with Lachancea fermentati Inhibitor Extracted from Rotten Grapefruits (Vitis vinifera): Adsorption, Thermodynamic, Electrochemical, and Quantum Chemical Studies

“…The XPS spectrum of Lachancea fermentati isolate biofilm adhesion on MS surface revealed the presence of carbon (C), iron (Fe), oxygen (O), and nitrogen (N) elements (Figure e). Figure a shows the binding energy value at 281.95 eV for the C 1s state because of the presence of the C–C bond in Lachancea fermentati isolate. ,, Figure b exhibits the binding energy value at 398.56 eV for the N 1s state because of the −CO–NH (imide) bond. ,, Figure c exhibits the binding energy (eV) value at 526.00 eV for the O 1s chemical state. Figure d shows the binding energy values at 715.03 eV for Fe–OOH/Fe 2 O 3 , at 718.80 eV for Fe–OOH, and at 735.62 eV for Fe 3+ peaks for iron atoms. , The elements, such as carbon (C), iron (Fe), oxygen (O), and nitrogen (N), were confirmed, and the aforementioned elements were involved for the formation of biofilm (protective layer) over the surface of MS via electrostatic interactions.…”

“…Figure 11a shows the binding energy value at 281.95 eV for the C 1s state because of the presence of the C−C bond in Lachancea fermentati isolate. 61,67,68 Figure 11b exhibits the binding energy value at 398.56 eV for the N 1s state because of the −CO−NH (imide) bond. 55,56,61 Figure 11c exhibits the binding energy (eV) value at 526.00 eV for the O 1s chemical state.…”