Evaluation of endemic Chilean plant‐based Chañar extract (Geoffroea decorticans) as an inhibitor of corrosion for A36 steel under a saline environment

Abstract

The use of inhibitors is one of the most practical modern methods in preventing and protecting against metal and alloy pipe corrosion. Exploring such additional inhibitors, particularly of natural origins, has become a key area of research. The present work, thus, evaluates the extract of a desert plant fruit, endemic to northern Chile, called Chañar (Geoffroea decorticans), as an inhibitor for the corrosion of A36 steel under a saline environment. Extract inhibition efficiency was evaluated by mass loss, polarization curves, and electrochemical impedance spectroscopy, and surface morphology of the steel after assays was analyzed by scanning electron microscopy. Results showed the formation of a smooth surface on the steel in the presence of the extract and a rough surface in the absence of the extract; also, polarization curves indicated an inhibition efficiency of approximately 82% at a concentration of 200ppm extract, corroborated by electrochemical impedance spectroscopy. The adsorption of the extract on the steel surface follows Langmuir's isotherm model, for which thermodynamic parameters suggest a physisorption mechanism.

Insight into corrosion inhibition mechanism of carbon steel by an algal extract as an eco‐friendly corrosion inhibitor in 0.5 M H2SO4: Experimental and molecular dynamics study

“…On the other hand, if the E corr shift <±85 mV, the inhibitor is of mixed electrochemical type. [ 31,32 ] In our study, the maximum displacement of E corr was −24.5 mV. These findings suggest that our inhibitor has mixed electrochemical behavior, as it acts by decreasing the anodic dissolution rate of the steel and reducing H + proton.…”

Analysis of inhibitory properties of Ce‐citrate as a green corrosion inhibitor of low alloy steel in neutral chloride solution

“…Also, a large number of papers are dedicated to finding ecologically friendly corrosion inhibitors obtained from extracts of various plants. [9][10][11][12][13][14][15] In the 1990s, Hinton [16] showed that rare earth metal chlorides (Y, Nd, Ce, La, etc.) are effective corrosion inhibitors of many metals and alloys in NaCl solutions, including steels.…”

“…Also, a large number of papers are dedicated to finding ecologically friendly corrosion inhibitors obtained from extracts of various plants. [ 9–15 ]…”