Search Results for organic chemicals

The susceptibility of plastics to environmental failure, when exposed to organic chemicals, limits their use in many applications. Environmental factors can be classified into two categories: chemical and physical effects. This article discusses the effects of these environmental factors on the mechanical properties of plastics.

Organic coatings (paints and plastic or rubber linings), metallic coatings, and nonmetallic inorganic coatings (conversion coatings, cements, ceramics, and glasses) are used in applications requiring corrosion protection. These coatings and linings may protect substrates by three basic mechanisms: barrier protection, chemical inhibition, and galvanic (sacrificial) protection. This chapter begins with a section on organic coating and linings, providing a detailed account of the steps involved in the coating process, namely, design and selection, surface preparation, application, and inspection and quality assurance. The next section discusses the methods by which metals, and in some cases their alloys, can be applied to almost all other metals and alloys: electroplating, electroless plating, hot dipping, thermal spraying, cladding, pack cementation, vapor deposition, ion implantation, and laser processing. The last section focuses on nonmetallic inorganic coatings including ceramic coating materials, conversion coatings, and anodized coatings.

All materials are susceptible to corrosion or some form of environmental degradation. Although no single material is suitable for all applications, usually there are a variety of materials that will perform satisfactorily in a given environment. The intent of this chapter is to review the corrosion behavior of the major classes of metals and alloys as well as some nonmetallic materials, describe typical corrosion applications, and present some unique weaknesses of various types of materials. It also aims to point out some unique material characteristics that may be important in material selection, and discuss, where appropriate, the characteristic forms of corrosion that attack specific materials. The materials addressed in this chapter include carbon steels, weathering steels, and alloy steels; nickel, copper, aluminum, titanium, lead, magnesium, tin, zirconium, tantalum, niobium, and cobalt and their alloys; polymers; and other nonmetallic materials, including rubber, carbon and graphite, and woods.

This chapter discusses corrosion prevention methods used with aluminum and its alloys. The methods range from relatively straightforward measures, such as proper handling and storage, to advanced early warning corrosion monitoring systems for military aircraft. The chapter summarizes the basic factors that influence design for corrosion resistance and discusses the use of conversion coatings, organic coatings, porcelain enameling, and electroplating. It also discusses corrosion monitoring methods used in chemical processing and refining industries.

This chapter provides an introduction to induction soldering. It also illustrates the classification of the different soldering processes according to the heat source, as described in the German standard, Soldering: Categorization of Processes According to Energy Sources, Process Descriptions.

This chapter covers the engineering aspects of corrosion inhibitors and their effect on corrosion reactions. It explains how different metallic salts and heterocyclic compounds influence chemical reactions on metal surfaces exposed to corrosive media or environments. It describes how to evaluate inhibition efficiency through weight loss measurements, linear polarization resistance tests, electrochemical impedance spectroscopy, electrochemical noise monitoring, and surface analysis. It demonstrates the use of potentiodynamic polarization curves, Tafel extrapolations, equivalent circuit models, and various methods for characterizing corrosion damage and protective surface films. It also discusses typical applications, industry trends, and the emerging role of high-throughput experimentation, quantitative modeling, and machine learning in the development of cleaner and more effective corrosion inhibitors.

The basic concept for most methods of corrosion protection is to remove one or more of the electrochemical cell components so that the pure metal or metal alloy of interest will not corrode. Another widely used corrosion protection approach is to change the nature of the anode so that it becomes the cathode (cathodic protection). This chapter briefly reviews these methods of corrosion protection. The factors affecting corrosion behavior are covered. In addition, the chapter provides information on coatings and inhibitors, which are used in corrosion protection.

This chapter focuses on the effects of microscopic organisms and the by-products they produce on the electrochemical corrosion of metals. It begins by considering the characteristics of organisms that allow them to interact with the corrosion processes, the mechanisms by which organisms can influence the occurrence or rate of corrosion, and the types of corrosion most often influenced by microbes. The chapter then discusses the formation of biofilms on the surface of metals. This is followed by a list of industries most often reported as being affected by microbiological corrosion, along with the organisms usually implicated in the attack. The types of attack that have most commonly been documented are illustrated through generalized case histories for different classes of alloys. The chapter also describes the general approaches to be taken to prevent microbiologically influenced corrosion. It ends with some information on the inhibition of corrosion by the action of bacteria.

This chapter presents the early classes of stainless steel. These include martensitic alloys, austenitic alloys, and ferritic alloys. It also presents stainless steel trade names. The chapter describes standardized designation for type 304 stainless steel by various specification organizations.

This chapter presents the Unified Numbering System (UNS) for metals and alloys.

In 1924, the American Society for Testing and Materials (ASTM) organized the symposium "Corrosion and Heat Resisting Alloys, and Electrical Resistance Alloys." It was the beginning of a major role that ASTM played in the history of stainless steel. This chapter provides information on the papers presented at the 1924 symposium. It also describes the role of ASTM in stainless steel standardization after the 1924 symposium.

This chapter provides a detailed account of corrosion inhibitors for oil and gas production. It begins by discussing some of the demands of competitive industry on inhibitor formulations. It then describes the varying characteristics of oil wells, gas wells, water injection systems, and pipelines. The following sections provide information on the factors influencing corrosivity of produced fluids and the methods of inhibitor application. The chapter discusses the primary causes of corrosion problems and inhibition in waterfloods and provides an overview of bacteria-induced corrosion. Various laboratory testing methods of corrosion inhibitors and the methods used to monitor corrosion rates and inhibitor effectiveness are also presented. The chapter ends by providing information on quality control of inhibitors and computerization of inhibitor treating programs.

This appendix provides information on organizations that issue specifications and standards related to titanium and its alloys.

This chapter presents the following groupings of metals and alloys that are soldered together: steel and iron-base alloys, aluminum and aluminum alloys, and copper and copper alloys. It also presents the ancillary materials and process methods that assist the solder filler metal in completing the solder joint through induction heating. The chapter focuses on the selection of fluxes and the use of inert gases or even vacuum to realize an oxide-free base material surface both before and during the soldering process.

Aluminum products are used extensively in natural atmospheres and in and around water. They are also widely used in building materials and as containers for chemicals and food and beverage products. This chapter discusses the corrosion mechanisms associated with these environments and the influence of various factors and prevention methods. It also includes an extensive amount of data of corrosion rates, corrosion resistance, and changes in mechanical properties.

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.

This chapter discusses the engineering significance of steel and briefly describes its chemical composition, crystal structure, Fe-C phases, and associated characterization techniques.

This chapter contains sample problems with worked solutions pertaining to the application of corrosion inhibitors. Correct answers require an understanding of potentiodynamic polarization scan (PDS) curves, the determination of corrosion current and inhibitor efficiency, and the development of a test plan to evaluate the long-term corrosion protection of a potential inhibitor.

The management of a failure analysis (FA) laboratory requires a broad range of activities to optimize the efficiency of the operation. The purpose of this article is to stimulate readers to consider the various aspects of FA laboratory operations and their respective business management requirements. The various aspects include: staffing, laboratory organization, lab design and operations, strategic development, financial management, and metrics and measurements. References for further reading and examples of resource materials are also included.