Preface

Progress in the field of corrosion mitigation has been commendable in recent years. As the use of metals and alloys increased throughout the world, the problem of corrosion increased simultaneously. The available methods do not provide ample solutions to the existing problems. So, the area is wide open to explore and develop further options and provide suitable mitigation to the corrosion of metals and alloys. Among the active methods, use of inhibitors is common and is used globally due to ease of usage, availability, and low cost.

The strict environmental guidelines and measures do not allow the usage of organic inhibitors in high concentrations. Therefore, the development of inhibitors is mostly focused on green principles and eco-friendly nature. The inhibitors prepared following the green principles are environmentally benign and serve as a potential solution to mitigate corrosion in petroleum industries and refineries. Different inhibitors have been reported with several formulations for industries to delay the corrosion process. To explain the mechanism of inhibitor action, several examples have been included with appropriate equations for different metals in different aggressive media. Detailed emphasis has been given to determine the corrosion rate using various available techniques. Several chapters have been included in this book to elaborate the mechanisms of inhibitor action in different corrosive solutions.

Apart from traditional studies, quantum studies have been used extensively to support the experimental findings. The introduction of density functional theory has strongly influenced the explanations of mechanisms and surface phenomena. Basic concepts such as chemical potential, chemical hardness, electronegativity, electrophilicity, and nucleophilicity play important roles in the prediction of reaction mechanisms and the analysis of chemical reactions. One chapter written by Dr. Ambrish Singh has been included that mainly focuses on the use of quantum studies in corrosion inhibition.

Tribocorrosion is one of the hot topics in corrosion research that involves materials and mechanical aspects altogether. Tribocorrosion damage (i.e., material loss) can be designated in a broad sense as a failure mechanism due to the mutual interaction of corrosion, friction, and wear processes and their synergy effects. It generates changes in surface and/or volume compositions, often modifies the environment, and ultimately can lead to system failure. The chapters by Dr. Abdenacer Berradja include overall insights into tribocorrosion in this book.

**II**

**Section 3**

Fundamentals of Electrolytic Corrosion

Methods for the Assessment of Corrosion Rates

*by Abdenacer Berradja*

*by Abdenacer Berradja*

Tribocorrosion **141**

**Chapter 8 143**

**Chapter 9 167**

Electrochemical Techniques for Corrosion and Tribocorrosion Monitoring:

Electrochemical Techniques for Corrosion and Tribocorrosion Monitoring:

Finally, I would like to thank all the committee members of IntechOpen along with all authors and reviewers for their invaluable contributions.

> **Dr. Ambrish Singh** School of Materials Science and Engineering, Southwest Petroleum University, Chengdu, Sichuan, China

> > **1**

Section 1

Inhibitors

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan, China

Section 1 Inhibitors

**3**

**Chapter 1**

**Abstract**

inhibitor

**1. Introduction**

large economic cost to the society [6].

rise their funds for demand of corrosion inhibitors [9].

**2. Historical background**

Corrosion Inhibitors

Corrosion is a natural process driven by energy consideration. Inhibition is a preventive measure against corrosive attack on metallic materials. Corrosion inhibitors have been frequently studied, since they offer simple solution for protection of metals against corrosion in aqueous environment. Mineral acids like hydrochloric and sulfuric acids are most widely used in pickling baths to remove the metal oxides formed on the surface. The multidisciplinary aspect of corrosion problems combined with the distributed responsibilities associated with such problems only increase the complexity of the subject. Inhibitors are used in industrial and com-

mercial processes to minimize both the metal loss and acid consumption.

**Keywords:** corrosion inhibitors, acidic inhibitors, volatile inhibitors, vapor phase

Corrosion is the primary means by which metals deteriorate. Corrosion introduces itself into many parts of our lives [1, 2]. The great majority of us have personal feeling for the importance of corrosion. Far too many have cringed at the emergence of rust holes in the body panels of relatively new automobiles [3]. The outdoor rusting of steel, household and garden appliances is a common fact of life. All have seen the strains on cooking utensils from hot foods or experienced the metallic taste in acid foods stored too long on open cans. That these effects are caused by corrosion is well known [4]. The glaring example related to corrosion is the appearance of cracks in certain portions of Taj Mahal, was due to steel dowels embedded inside had extensively corroded and rusted leading to fractures in the stoned [5]. However, corrosion is just as common in other material classes such as ceramics, plastics and rubber. Since, practically all environments are corrosive to some degree and are major contributing causes of material failure and also are a

Corrosion can be viewed as a universal phenomenon, omnipresent and omnipotent. It is there everywhere, air, water, soil and in every environment, we encounter [7]. Known to people as rust, corrosion is an undesirable phenomenon which destroys the luster and beauty of the materials and lessens their life. Indian government spending around 3.5% Lakscrores of the nation's GDP per annum for losses of corrosion [8]. Recent studies estimate that, not only in India, other countries also

*Geethamani Palanisamy*
