Nonelectrochemical Techniques in corrosion inhibition studies: Analytical techniques

Abstract

Humphrey Sam Samuel^, Ugo Nweke-Maraizu, Gani Johnson, and Emmanuel Edet Etim

Corrosion is a widespread issue that impacts many different businesses and infrastructures, causing major financial losses and safety risks. Chemical substances known as corrosion inhibitors can be added to gases or liquids to slow down the rate of corrosion of metals in contact with an aggressive medium. The corrosion inhibition efficiency of a given inhibitor can be influenced by several factors including, temperature, concentration of inhibitor, the type of aggressive medium, etc. In this study, nonelectrochemical methods of analyzing the corrosion of metals have been reviewed. All the methods are observed to have a common principles of monitoring the changes in the structure, surface and other observable properties of the metal, in the absence and presence of the inhibitor. An inhibitor is accepted in this work, only if it can inhibit corrosion, when presence in a minute concentration.  In the light of examining the chemical make-up and molecular structure of corrosion inhibitors, spectroscopic methods such as NMR and GCMS are upheld. FTIR and Raman spectroscopy are useful in analyzing the functional groups in the inhibitor or the corrosion products, without and in the presence of the inhibitor.  XPS offers insight into the elemental composition and oxidation states of the metal surface and inhibitor film. It is the recommendation of the authors that a comprehensive approach to analyzing corrosion inhibition requires the adoption of different methods that can provide information concerning the inhibition.