Metronidazole mediated potassium iodide as high-performance deterioration retardant for mild steel in an acidic media

Abstract

As corrosion scientists all over the world struggle to discover new metal deterioration retardant which can close the performance gap created by the legislative banned toxic inhibitors, we present in this research work an azole based drug and its mediation performance with a synergistic agent as ‘green’ metal degradation retardant. The anti-deterioration performance of the azole-based drug, metronidazole (MTN) and its different concentration combinations with potassium iodide (KI) were examined with materials degradation analysis tools such as functional group, nanoindentation, weight loss and electrochemical techniques. MTN alone performed well as an anti-deterioration retardant exhibiting retardation efficiencies (η%) in the range between 73 to 85% at different temperatures and analytical techniques. However, with the introduction of KI, an escalation in (η%) was obtained in the region of 92 to 97%. In addition, improved polarization resistance of chemical retardants on substrate cross sections was achieved, manifested by the resultant elevation in values of polarization resistances (R_p) from 1.54 Ω.cm² of the blank to 30.61 Ω.cm² of the optimum concentration, charge transfer resistances, (R_ct) improved likewise from 6.03 to 144.07 Ω.cm² and depreciation in the values of corrosion current densities (I_corr) from 8863.86 to 228.89 µA.cm². This work describes a method of improving the metal deterioration retardation potentials of an azole compound, bringing out new knowledge on the degradation inhibition properties of MTN and the adsorption process taking place between the substrate and the belligerent environment. We hope it opens the door for the utilization of a mixture of MTN and KI as additives for the formulation of sealants, paints, conversion coatings and primers for ferrous alloys. It also encourages more investigations, to find additives such as suitable activating and accelerating agents for MTN to make It exercise the same or more anti-corrosion potents possessed by the banned hexavalent chromium (vi), benzothiazoles (BTA) and others. Some of these potents are the ability of MTN to function at a wide region of pH and in the moment of coating failure, what can enable an azole-containing coating, to undergo some chemical activities and still maintain the substrate surface integrity?

Graphical Abstract

Keywords:

• Metronidazole
• mild steel
• polarization
• deterioration
• retardant
• synergism
• occluding

Acknowledgments

We acknowledge the efforts of other Staff of African Development Bank Laboratory during the process of this research, and in fact the Management of African University of Science and Technology, Abuja, Nigeria, especially our University President Prof. Peter Onwualu for providing all the equipment we used to carry out this research.

Disclosure statement

We the Authors of this research work solemnly declare that we have no conflict of interest of any form with any body or person concerning this work. The authors declare that we have no relevant support either in form of financial or non-financial term to disclose.