Fundamentals of corrosion chemistry

Abstract We live in a metal-based society where the use of metallic materials at all levels is common. These metallic materials (alloys and metals) are subject to an unavoidable but controllable phenomenon referred to as corrosion. When these materials corrode, they lose their physical and chemical properties, which poses great concern to individuals, industries, and the government of the nations of the world. Corrosion has a great effect on human life and the economy, just as much as natural disasters such as earthquakes, floods, and tsunamis. Understanding the corrosion phenomena is an important step in proffering plausible solutions by experts in the field of corrosion science and engineering. Corrosion occurs as uniform (general) or nonuniform corrosion. In uniform corrosion, the entire bare surface of the metal deteriorates while in nonuniform corrosion, uneven deterioration of the metallic surface takes place. Corrosion is generally known to be an electrochemical process involving anodic oxidation and cathodic reduction in the presence of an electrolyte. Industrial metals behave differently in various electrolytic media. Over the years, several corrosion protection methods have been proposed to check the rate of metallic corrosion. Electrochemical techniques such as linear polarization, electrochemical impedance spectroscopy, and potentiodynamic polarization have been widely employed to monitor the rate of corrosion in the laboratory and industry. This chapter explores the basis of corrosion studies, various forms of corrosion, the chemistry behind electrochemical corrosion of common industrial metals, kinetics and thermodynamics, methods of corrosion protection, and monitoring techniques.