This chapter outlines the major types of corrosion, their interactions, their complicating effects on fracture and wear, and some possible prevention methods. The types of corrosion considered in the chapter are galvanic corrosion, uniform corrosion, pitting corrosion, crevice corrosion, microbiologically influenced corrosion, stress-corrosion cracking, and corrosion fatigue.

This chapter covers the corrosion behavior of beryllium in aqueous environments. It describes the chemical reactions that drive the corrosion process, the conditions required for equilibrium, and the factors that affect corrosion resistance. It discusses the stability of the native oxides that form on the surface of beryllium and their ability to withstand acids, bases, and corrosive agents found in rain and seawater. It explains how carbides, inclusions, ions, and impurities contribute to corrosion damage, particularly pitting, and how corrosion reduces the ductility and fracture strength of certain beryllium alloys.

This chapter discusses the principles of corrosion of metals in aqueous environments. The thermodynamics of aqueous corrosion is the subject of the first half of this chapter, which addresses concepts such as corrosion reactions and free-energy change, the relationship between free energy and electrochemical potential, the effect of ionic concentration on electrode potential, and the corrosion behavior of a metal based on its potential-pH diagram. The corrosion (potential-pH) behavior of iron, gold, copper, zinc, aluminum, and titanium are described. Understanding the kinetics of corrosion and the factors that control the rates of corrosion reactions requires examination of the concepts of polarization behavior and identification of the various forms of polarization in an electrochemical cell. These concepts, addressed in the remaining of this chapter, include anodic and cathodic reactions, the mixed-potential theory, and the exchange currents.

This chapter discusses the formation and control of aqueous corrosion in iron and steel. It also provides information on passivation, stress corrosion, rust, and direct oxidation.

Corrosion problems can be divided into eight categories based on the appearance of the corrosion damage or the mechanism of attack: uniform or general corrosion; pitting corrosion; crevice corrosion, including corrosion under tubercles or deposits, filiform corrosion, and poultice corrosion; galvanic corrosion; erosion-corrosion, including cavitation erosion and fretting corrosion; intergranular corrosion, including sensitization and exfoliation; dealloying; environmentally assisted cracking, including stress-corrosion cracking, corrosion fatigue, and hydrogen damage (including hydrogen embrittlement, hydrogen-induced blistering, high-temperature hydrogen attack, and hydride formation). All these forms are addressed in this chapter in the context of aqueous corrosion. For each form, a general description is provided along with information on the causes and the list of metals that can be affected, with particular emphasis on the recognition and prevention measures.

Corrosion can be defined as a chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties. This chapter describes the effects and economic impact of corrosion in major industrial plants. The emphasis in this chapter, as well as in other chapters in this book, is on aqueous corrosion, or corrosion in environments where water is present. The chapter describes the classification of various forms of corrosion based on the nature of the corrodent, mechanism of corrosion, and appearance of the corroded metal. It discusses five primary methods of corrosion control, namely, material selection, coatings, inhibitors, cathodic protection, and design. Examples of the opportunities in corrosion control and the means to implement a program to capitalize on those opportunities are presented in a table. The chapter concludes with varied sources of information pertaining to corrosion and corrosion prevention.

Nickel-base alloys used for low-temperature aqueous corrosion are commonly referred to as corrosion-resistant alloys (CRAs), and nickel alloys used for high-temperature applications are known as heat-resistant alloys, high-temperature alloys, or superalloys. The emphasis in this chapter is on the CRAs and in particular nickel-chromium-molybdenum alloys. The chapter provides a basic understanding of general welding considerations and describes the welding metallurgy of molybdenum-containing CRAs and of nickel-copper, nickel-chromium, and nickel-chromium-iron CRAs. It discusses the corrosion behavior of nickel-molybdenum alloys and nickel-chromium-molybdenum alloys. Information on the phase stability and corrosion behavior of nickel-base alloys is also included.

This chapter familiarizes readers with the basic concepts of corrosion, discussing chemical reactions, ion transfer mechanisms, electrochemical processes and variables, and the formation of solid corrosion products. It presents a simple but effective teaching tool, the elementary electrochemical corrosion circuit, using it to explain how electric potential differences drive the corrosion process and how corrosion rates vary in proportion to current density. The chapter concludes with a discussion on the importance of corrosion products, such as oxides and hydroxides, and how their formation can be a major factor in controlling corrosion.

This chapter describes various units and process streams that are often susceptible corrosion inhibitors in crude oil refineries, discusses the types and applications of corrosion inhibitors, and provides some information on corrosion monitoring techniques used at refineries.

This chapter outlines the step-by-step processes by which materials are selected in order to prevent or control corrosion and includes information on materials that are resistant to the various forms of corrosion. The various forms of corrosion covered are general (uniform) corrosion, localized corrosion, galvanic corrosion, intergranular corrosion, stress-corrosion cracking, hydrogen damage, and erosion-corrosion. In addition, the economic importance of cost-effective materials selection is also considered.

This chapter addresses the basic concepts important to understanding corrosion of metals. It begins with an overview of the three types of behaviors that a metal exhibits when immersed in an environment and of the four requirements of a corrosion cell. The chapter then covers the important characteristics of metals with respect to corrosion, namely the metallurgical characteristics, the inherent tendency to corrode, and the tendency to form insoluble corrosion products. The important characteristics of aqueous solutions with respect to corrosion are then addressed. The characteristics include: conductivity of the solution, acidity and alkalinity, oxidizing power, degree of ionization, and solubility in the solution. These characteristics, in combination with the characteristics of the metal, will determine the corrosion behavior of a metal/environment combination. The chapter concludes with a section on the determination of corrosion rates and corrosion rate allowances.

This chapter presents the primary considerations and mechanisms for corrosion and how they are involved in the selection of materials for process equipment in petroleum refineries and petrochemical plants. In addition, specific information on mechanical properties, corrosion, sulfide stress cracking, hydrogen-induced cracking, stress-oriented hydrogen-induced cracking, hydrogen embrittlement cracking, stress-corrosion cracking, velocity-accelerated corrosion, erosion-corrosion, and corrosion control is provided.

Nonferrous metals are of commercial interest both as engineering materials and as alloying agents. This chapter addresses both roles, discussing the properties, processing characteristics, and applications of several categories of nonferrous metals, including light metals, corrosion-resistance alloys, superalloys, refractory metals, low-melting-point metals, reactive metals, precious metals, rare earth metals, and metalloids or semimetals. It also provides a brief summary on special-purpose materials, including uranium, vanadium, magnetic alloys, and thermocouple materials.

This chapter addresses the issue of stress-corrosion cracking (SCC) in carbon and low-alloy steels. It discusses crack initiation, propagation, and fracture in aqueous chloride, hydrogen sulfide, sulfuric acid, hydroxide, ammonia, nitrate, ethanol, methanol, and hydrogen gas environments. It explains how composition and microstructure influence SCC, as do mechanical properties such as strength and fracture toughness and processes such as welding and cold work. It also discusses the role of materials selection and best practices for welding.

This chapter describes the conditions under which copper-base alloys are susceptible to stress-corrosion cracking (SCC) and some of the environmental factors, such as temperature, pH, and corrosion potential, that influence crack growth and time to failure. It explains that, although most of the literature has been concerned with copper zinc alloys in ammoniacal solutions, there are a number of alloy-environment combinations where SCC has been observed. The chapter discusses several of these cases and the effect of various application parameters, including composition, microstructure, heat treatment, cold working, and stress intensity. It also provides information on stress-corrosion testing, mitigation techniques, and basic cracking mechanisms.

This chapter provides an introduction to various forms of corrosion, namely uniform corrosion, localized corrosion, mechanically assisted degradation, environmentally induced cracking, microbiologically influenced corrosion, and metallurgically influenced corrosion.