Mass transfer influence on the corrosion inhibition of N80 steel in 1 M H₂SO₄ by green corrosion inhibitor using MATLAB

The corrosion process of steel alloys in acidic environments is typically considered to be governed by charge transfer (activation) control. Nonetheless, in aerated solutions, mass transfer can affect the electrochemical measurements. This study examines the corrosion inhibition of N80 steel in 1 M sulfuric acid using okra leaf extract (OLE), utilizing electrochemical polarization techniques at various concentrations of the inhibitor and different temperatures. The outcomes of electrochemical data of current densities and overpotentials were fitted to a high-order polynomial equation and the Maclaurin series formula. The coefficients of the high-order polynomial equation were evaluated using a non-linear regression method, which is in turn used in the Maclaurin series formula. A series of complex equations were derived, incorporating a factor (β) to account for the impact of mass transfer on the activation-controlled corrosion process. A complex equation set of β-models was processed using MATLAB computer programming. In addition, a β-model was correlated to a mass transfer correction factor (γ) and polarization resistance (Rp). β-values ranged from 0.005 to 0.916 (average 0.198), which indicates the presence of a mass transfer effect in addition to the activation effect (mixed control corrosion mechanism). Conversely, the polarization resistance (Rp) increased with higher inhibitor concentrations and decreased as the temperature rose.</p

Okra leaves extract as green corrosion inhibitor for steel in sulfuric acid: Gravimetric, electrochemical, and surface morphological investigations

Utilizing plant extracts as an alternative source for corrosion inhibitors holds significant promise in minimizing the risk of corrosion. In this study, an okra leaf extract (OLE) was employed as a corrosion inhibitor for N80 steel in 1.0 M H2SO4. The corrosion rate was assessed concerning temperature (30, 40, 50, and 60 °C) and inhibitor concentrations (blank, 25, 50, 75, and 100 ml/l) through weight loss and electrochemical polarization techniques. The results indicated that OLE functions as a mixed-type corrosion inhibitor, with corrosion rates increasing with temperature and decreasing with inhibitor concentration. The maximum corrosion inhibition efficiency reached 96 % at 30 °C and 100 ml/l. Adsorption studies revealed that OLE physically adsorbed onto the mild steel surface, following the Langmuir adsorption isotherm. Gravimetrical and electrochemical techniques were confirmed by FTIR and UV measurements, which showed the presence of a protective layer on the metal surface. Optical microscopy, AFM, and SEM images demonstrated the formation of a protective layer on the metal surface. Thermogravimetric analysis (TGA) highlighted the thermal stability exhibited by inhibitor molecules, which showed that OLE was thermally stable up to 85 °C