Volatile corrosion inhibitors for ferrous and non-ferrous metals and alloys: A review

• F.A. Ansari¹, C. Verma^2,3, Y.S. Siddiqui⁴, E.E. Ebenso^2,3 and M.A. Quraishi⁵

¹ Department of Applied Chemistry, JETGI, Faculty of Engineering, Barabanki, India-225203
² Department of Chemistry, School of Mathematical & Physical Sciences, Faculty of Agriculture, Science and Technology, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
³ Material Science Innovation & Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
⁴ Assistant Professor, Department of Civil Engineering, JETGI, Faculty of Engineering, Barabanki, India-225203
⁵ Center of Research Excellence in Corrosion, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

Abstract: Volatile corrosion inhibitors (VCIs) or vapor phase inhibitors (VPIs) represent a class of compounds that are employed to protect the corrosion or oxidation of ferrous and non-ferrous metals and alloys where other surface treatments are impractical. The VCIs release slowly inside the sealed airspace and actively adsorb and prevent corrosion. Several VCIs have been employed as effective inhibitors for several metals like iron, zinc, aluminum, etc. and their alloys. Literature study revealed that VCIs protect metallic corrosion either by forming a surface protective film on the metal surface or neutralizing the corrosive surrounding reagents H2O, SO2, H2S and CO2, etc. Because of the high volatility, VCIs easily vaporize and their vapors condense on the metallic surface as well as the volume available in the crevices, pores and cracks thereby gives complete protection where they used. The VCIs can be inserted into coatings, foams, adhesives, powders, sprays and plastics. Several VCIs are known those act as effective inhibitors by themselves and few other VCIs are also known those hydrolyzed products act as corrosion inhibitors. The inhibition ability as well as quantity of the adsorbed VCIs on metallic surfaces can be determined by several commonly employed techniques such as contact angle, radiotracer, polarographic and electrocapilarity methods. Present review article describes the assortment of previous works published on VCIs as corrosion inhibitors for ferrous and non-ferrous metals and alloys. The present report also deals with salient features of VCIs and mechanism of their action.

Keywords: VCIs, vapour pressure, corrosion inhibition, vapour phase inhibitors, DICHAN, mechanism of VCIs action

Int. J. Corros. Scale Inhib., 2018, 7, no. 2, 126-150 PDF (1 453 K)
doi: 10.17675/2305-6894-2018-7-2-2

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