Corrosive electrolytes

• C. Verma¹, M.A. Quraishi¹ and E.E. Ebenso^2,3

¹ Center of Research Excellence in Corrosion, Research Institute, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
² Department of Chemistry, School of Chemical and Physical Sciences & Material Science Innovation & Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
³ Department of Chemistry, College of Science, Engineering and Technology, University of South Africa, Florida, Roodepoort 1710, South Africa

Abstract: Metals and alloys are extensively used as constructional materials for household and industrial applications. However, most of the metals and their alloys are highly reactive and undergo rapid corrosion depending upon the nature of surrounding environment. The corrosive dissolution is more pronounced in the presence of aqueous electrolytes. Acidic aqueous solutions such as hydrochloric (HCl), sulphuric (H₂SO₄), nitric (HNO₃), phosphoric (H₃PO₄) and other inorganic or inorganic acid are some common industrially useful corrosive electrolytes. Along with acidic electrolytes, basic and neutral aqueous electrolytes have also been used as corrosive electrolytes. Present report describes the collection of some major corrosive electrolytes and the mechanism of metallic corrosion in such electrolytes. In this report, metallic surface cleaning using acidic solutions of hydrochloric (HCl), phosphoric acid (H₃PO₄), sulphuric acid (H₂SO₄), citric acid (C₆H₈O₇), hydrofluoric acid (HF), nitric acid (HNO3), formic acid (HCOOH), acetic acid (CH₃COOH), perchloric acid (HClO₄) and sulfamic acid (H₃NSO₃) has been described. More so, corrosion mechanism and surface cleaning using basic solutions such as sodium hydroxide (NaOH), potassium hydroxide (KOH) and ammonium hydroxide (NH₄OH) has also been described. Lastly, mechanism of corrosion in NaCl, NaCl saturated with CO₂ and CO₂+H₂S medium is described in this repost. Mechanism of metallic corrosion in oil, gas and petroleum industrial is also described in this report. This article will help academician and industrialists to find out different aqueous electrolytes being used as metallic surface treatment.

Keywords: electrolytes, aqueous solution, corrosion inhibitors, sweet and sour corrosion, acid pickling processes

Int. J. Corros. Scale Inhib., 2020, 9, no. 4, 1261-1276 PDF (325 K)
doi: 10.17675/2305-6894-2020-9-4-5

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