Natural products as corrosion inhibitor for metals in corrosive media — A review

Corrosion control of metals is of technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options of protecting metals and alloys against corrosion. The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors as they are biodegradable, do not contain heavy metals or other toxic compounds. As in addition to being environmentally friendly and ecologically acceptable, plant products are inexpensive, readily available and renewable. Investigations of corrosion inhibiting abilities of tannins, alkaloids, organic,amino acids, and organic dyes of plant origin are of interest. In recent years, sol-gel coatings doped with inhibitors show real promise. Although substantial research has been devoted to corrosion inhibition by plant extracts, reports on the detailed mechanisms of the adsorption process and identification of the active ingredient are still scarce. Development of computational modeling backed by wet experimental results would help to fill this void and help understand the mechanism of inhibitor action, their adsorption patterns, the inhibitor-metal surface interface and aid the development of designer inhibitors with an understanding of the time required for the release of self-healing inhibitors. The present paper consciously restricts itself mainly to plant materials as green corrosion inhibitors.

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Green Inhibitors for Corrosion Protection of Metals and Alloys: An Overview

Inhibitory action of Phyllanthus amarus extracts on the corrosion of mild steel in acidic media

Drugs: A review of promising novel corrosion inhibitors

The effects of Aloe vera extract on corrosion and kinetics of corrosion process of zinc in HCl solution

Purpose – To evaluate the corrosion inhibition potential of Datura metel in acid medium on mild steel (MS) with a view to develop green corrosion inhibitors.Design/methodology/approach – Acid extract of the D. metel was studied for its corrosion inhibitive effect by electrochemical and weight loss methods. Using weight loss measurement data, an attempt has been made to probe the mechanism of inhibitive action by fitting adsorption isotherms.Findings – D. metel has been found to show significant corrosion inhibitive effect in acid medium on MS. Inhibition is through adsorption of the phytoconstituents on MS following Tempkin and Langmuir adsorption isotherms. The results of A.C. impedance and polarisation studies correlate well with the weight loss studies.Originality/value – The plant has been investigated for the first time for its corrosion inhibitive effect. The effect has been studied by proven methods. This green inhibitor can find use in the inhibition of corrosion in industries where MS is used as ...

Corrosion inhibition of mild steel by Datura metel in acidic medium

The inhibition efficiency of the extract of Strychnos nux-vomica for the corrosion of mild steel in 1 M sulfuric acid was investigated using weight loss test (carried out at 303–323 K), electrochemical measurement, and scanning electron microscope (SEM). The results of weight loss studies indicated that the inhibition efficiency increased with inhibitor concentration and the temperature of the system (following Temkin adsorption isotherm). Electrochemical studies proved that the inhibitor acts through mixed mode of inhibition and the inhibitor molecules adsorb on the metal–solution interface. SEM studies supported the adsorption of the inhibitor over the metal surface. The possible active ingredient responsible for the anticorrosion effect is identified as brucine which is isolated and screened for the anticorrosion effect using electrochemical studies and quantum chemical studies. The possible mode of corrosion inhibition of brucine is also derived using FT-IR studies.

Strychnos nux‐vomica an eco‐friendly corrosion inhibitor for mild steel in 1 M sulfuric acid medium

Alkaloid extract of Rauvolfia serpentina was tested as corrosion inhibitor for mild steel in 1 M HCl and H2SO4 using weight loss method at three different temperatures, viz., 303, 313, and 323 K, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscope (SEM) studies. It is evident from the results of this study that R. serpentina effectively inhibits the corrosion in both the acids through adsorption process following Tempkin adsorption isotherm. The protection efficiency increased with increase in inhibitor concentration and temperature. Free energy of adsorption calculated from the temperature studies also revealed the chemisorption. The mixed mode of action exhibited by the inhibitor was confirmed by the polarization studies while SEM analysis substantiated the formation of protective layer over the mild steel surface.

Studies on the Inhibition of Mild Steel Corrosion by Rauvolfia serpentina in Acid Media

The corrosion inhibition potential of mild steel in 1M H2SO4 by Solanum nigrum extract was studied using weight loss method, potentiodynamic polarisation method, ac impedance studies and SEM technique. Weight loss measurements, carried out at three different temperatures, 303, 313 and 323 K, revealed the increase in inhibition efficiency with increasing concentration of the plant extract as well as the temperature of the system. Thus, the inhibitor exhibited the chemisorption mechanism following Temkin adsorption isotherm. Free energy of activation ΔG was also calculated so as to confirm the chemisorption process. Results of polarisation study revealed the mixed mode of inhibition. SEM studies supported the adsorption of inhibitor over the metal surface. The anticorrosion effect of S. nigrum is attributed to the presence of solasodine which was isolated and studied by theoretical, electrochemical and IR techniques. The possible adsorption mechanism of the inhibition is discussed vis-a-vis the pres...

P. Bothi Raja

Papers

Corrosion inhibition of mild steel by Datura metel in acidic medium

Strychnos nux‐vomica an eco‐friendly corrosion inhibitor for mild steel in 1 M sulfuric acid medium

Studies on the Inhibition of Mild Steel Corrosion by Rauvolfia serpentina in Acid Media

Solanum nigrum as natural source of corrosion inhibitor for mild steel in sulphuric acid medium

Corrosion inhibition of Pichia sp. biofilm against mild steel corrosion in 1 M H2SO4