Inhibition of corrosion of mild steel in well water by Phenolic compounds

Abstract

The present work is carried out with the objective of developing a new inhibitor formulation containing organic chemicals for the inhibition of corrosion of carbon steel in well water and also to inhibit the Microbial Induced Corrosion (MIC) by adding suitable biocides in open recirculating cooling systems. The inhibitors chosen for the present study are phenolic compounds viz., phenol, resorcinol, 1-naphthol, 2-naphthol, hydroquinone and Zn2+ is chosen as the synergist. The biocides selected for the present work are N-cetyl-N,N,N-trimethylammonium bromide, cetylpyridinium chloride and sodiumdodecyl sulphate. The influence of immersion period and pH on the inhibition efficiency of effective synergistic systems on the corrosion of carbon steel have also been investigated. In order to investigate the nature of the protective film, UV-Visible Absorption Spectroscopy, Luminescence Spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Fourier Transform- Infrared Spectroscopy (FTIR) have been used in the present study. The mechanistic aspects of corrosion inhibition are based on the classical weight loss method, the polarization study and different surface examination techniques. This thesis is divided into six chapters. Chapter I presents a general introduction to the nature and extent of corrosion problems, theories of corrosion, different forms of corrosion, corrosion control by inhibitors and theories of inhibition of corrosion. Review of literature on the corrosion inhibitors such as phenolic compounds, zinc ions and surfactants for carbon steel are discussed in Chapter II. Reviews on the synergistic study on the carbon steel and on the biocidal efficiency of certain biocides are also presented. The need, objectives and scope of the present study are discussed in Chapter III. Chapter IV explains the methodology employed in the present study.