Identification of alloys using quantitative chemical analysis is an essential step during a metallurgical failure analysis process. There are several methods available for quantitative analysis of metal alloys, and the analyst should carefully approach selection of the method used. The choice of appropriate analytical techniques is determined by the specific chemical information required, the condition of the sample, and any limitations imposed by interested parties. This article discusses some of the commonly used quantitative chemical analysis techniques for metals. The discussion covers the operating principles, applications, advantages, and disadvantages of optical emission spectroscopy (OES), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray spectroscopy, and ion chromatography (IC). In addition, information on combustion analysis and inert gas fusion analysis is provided.

This article briefly discusses popular techniques for metals characterization. It begins with a description of the most common techniques for determining chemical composition of metals, namely X-ray fluorescence, optical emission spectroscopy, inductively coupled plasma optical emission spectroscopy, high-temperature combustion, and inert gas fusion. This is followed by a section on techniques for determining the atomic structure of crystals, namely X-ray diffraction, neutron diffraction, and electron diffraction. Types of electron microscopies most commonly used for microstructural analysis of metals, such as scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy, are then reviewed. The article contains tables listing analytical methods used for characterization of metals and alloys and surface analysis techniques. It ends by discussing the objective of metallography.

The overall chemical composition of metals and alloys is most commonly determined by X-ray fluorescence (XRF) and optical emission spectroscopy (OES), and combustion and inert gas fusion analysis. This article provides information on the capabilities, uses, detection threshold and precision methods, and sample requirements. The amount of material that needs to be sampled, operating principles, and limitations of the stated methods are also discussed.

The electronic microcircuit industry has placed severe demands on metal suppliers to provide metals of the highest reproducible purity attainable as a result of the constant quest for the true values of physical and chemical properties of metals. This article describes the commonly used methods for ultrapurification of metals produced by electrolytic processes, including fractional crystallization, zone refining, vacuum melting, distillation, chemical vapor deposition, and solid state refining techniques. In addition, it describes the trace element analysis and resistance-ratio test methods used to characterize purity. Tables list the values for resistance ratios of zone-refined metals and their corresponding chemical compositions, and provide an example of the detection of impurities to concentrations in the parts per billion range, utilizing a combination of the glow discharge mass spectroscopy method and Leco combustion methods.

This article presents the major thermal spray processes and their subsets, presenting each of the commercially significant processes together with some of their important variations. Each process is presented along with the attributes that influence coating structure and performance. The article summarizes the essential equipment components and necessary controls. The various thermal spray processes are conventional flame spray, detonation gun, high-velocity oxyfuel spray, electric arc spray, and plasma arc spray. Other processes, such as cold spray, underwater plasma arc spray, and extended-arc and other high-energy plasma arc spray, are also considered.

This article provides an overview of the concepts of environmental, health, and safety (EH&S) risk incidents, then discusses these concepts relative to additive manufacturing (AM): the multiple intrants, process parameters, and equipment, as well as the resulting products and wastes. The article discusses additive manufacturing hazards, which are broken down into material hazards, equipment/process hazards, and facility hazards. The environmental impact of AM and the development of EH&S standards for AM also are covered in the article.

This article provides an overview of the supply chain for metallic additively manufactured materials, with an emphasis on spherical alloy powders. The article describes powder production processes as well as the various metal alloys that can be produced using powder AM techniques. It also reviews the basic characteristics of powder feedstocks and the management of metallic powders.

This article provides information on the liquid lithium systems that are exposed to liquid metal. It discusses the forms in which liquid-metal corrosion is manifested. The influence of several key factors on the corrosion of metals and alloys by liquid-metal systems or liquid-vapor metal coolants is described. Some information on safety precautions for handling liquid metals, operating circulating systems, dealing with fire and spillage, and cleaning contaminated components, are also provided.

This article introduces thermal spray coatings and describes the various types of coating processes and coating devices, including the flame spray, electric-arc spray, plasma spray, transferred plasma arc, high-velocity oxyfuel, and detonation gun. It provides information on the surface preparation methods and finishing treatments of coated parts. The article also explains the tests to evaluate the coating quality and the effects of coating structures and mechanical properties on coated parts. It concludes with a discussion on the uses of thermal spray coatings.

This article discusses the capabilities and limitations of various material characterization methods that assist in the selection of a proper analytical tool for analyzing particulate materials. Commonly used methods are microanalysis, surface analysis, and bulk analysis. The techniques used for performing microanalysis include scanning electron microscopy and electron probe X-ray microanalysis. The article describes surface analysis techniques, including Auger electron spectroscopy, X-ray photoelectron spectroscopy, and ion-scattering spectroscopy. Bulk analysis techniques, such as X-ray powder diffraction, inductively coupled plasma atomic emission spectroscopy, atomic absorption spectroscopy, and atomic fluorescence spectrometry, are also discussed.

This article provides information on basic chemical equilibria, wet analytical chemistry, and the appropriateness of classical wet methods. It focuses on nonoxidizing acids and oxidizing acids. The article includes information on the qualitative methods used to identify materials by wet chemical reaction. Gravimetry, in which a chemical species is weighed; titrimetry, which involves volume measurement of a liquid reactant; and a host of separation techniques, which require diverse forms of laboratory manipulation, are discussed. The article briefly describes the partitioning of oxidation states as well as those applications in surface studies and rapid material identification in which chemical techniques have proved useful.

Quality control of cemented carbides includes the evaluation of physical and chemical properties of constituent raw material powders, powder blends/formulations, green compacts, and fully dense finished product. This article provides a summary of the underlying principles and size ranges for the American Society for Testing and Materials (ASTM) standard methods of particle sizing and distribution. It presents the methods used to analyze the chemical composition of cemented carbide materials in a tabular form. The article also presents information on microstructural evaluation and physical and mechanical property evaluation of cemented carbides.

Ceramic coatings are applied to metals to protect them against oxidation and corrosion at room temperature and at elevated temperatures. This article provides a detailed account of the factors to be considered when selecting a ceramic coating and describes the characteristics of various coating materials, namely, silicate glasses, oxides, carbides, silicides, and cermets. It reviews ceramic coating methods: brushing, spraying, dipping, flow coating, combustion flame spraying, plasma-arc flame spraying, detonation gun spraying, pack cementation, fluidized-bed deposition, vapor streaming, troweling, and electrophoresis. The article also includes information on the evaluation of the quality of ceramic coatings.

This article focuses on wet chemical methods that have stood the test of time in laboratories around the world. It begins with a description of the appropriateness of classical wet methods. This is followed by sections on sampling procedures, basic chemical equilibria, and wet analytical chemistry. Mechanical methods and nonoxidizing acids and/or acid mixtures for dissolving solid samples for wet chemical analysis are then reviewed. Qualitative methods that are used to identify materials by wet chemical reaction are also included. The article provides information on various methods for the separation of chemical mixtures and on the types of gravimetry and titrimetry. Strategies for removing inclusions are also included to aid in their compositional understanding. The article also briefly describes the processes involved in chemical surface studies and partitioning of oxidation states. It ends by presenting some examples of the applications of classical wet methods.

Case depth is the normal distance from the surface of the steel to the start of the core. Measurement of case depth is highly sensitive to the type of case hardening, original steel composition, quenching condition, and even to the testing method. This article describes the various methods of measuring case depth in steels, including chemical methods such as the combustion analysis and spectrographic analysis, microhardness test method, macroscopic and microscopic visual methods, and nondestructive methods. It contains a table that provides approximate equivalent hardness numbers for steel.

This article is a detailed account of additive manufacturing (AM) processes for copper and copper alloys such as copper-chromium alloys, GRCop, oxide-dispersion-strengthened copper, copper-nickel alloys, copper-tin alloys, copper-zinc alloys, and copper-base shape memory alloys. The AM processes include binder jetting, ultrasonic additive manufacturing, directed-energy deposition, laser powder-bed fusion, and electron beam powder-bed fusion. The article presents a review of the literature and state of the art for copper alloy AM and features data on AM processes and industrial practices, copper alloys used, selected applications, material properties, and where applicable, compares these data and properties to traditionally processed materials. The data presented and the surrounding discussion focus on bulk metallurgical processing of copper components. The discussion covers the composition and performance criteria for copper alloys that have been reported for AM and discusses key differences in process-structure-property relationships compared to conventionally processed material. The article also provides information on feedstock considerations for copper powder handling.

Ion chromatography (IC) is an analytical technique that uses columns packed with ion exchange resins to separate ions in aqueous solutions and dynamically elute them to a detector. This article provides information on the different modes of detection, namely, eluent-suppressed conductivity detection, single-column ion chromatography with conductivity detection, ion chromatography with spectrophotometric detection, and amperometric electrochemical detection. It describes the modes of separation techniques in IC and reversed-phase IC. The article discusses the detection capabilities of IC, the procedures for preparing solid and liquid samples, as well as the applications of IC.

The primary market for metal powder is the production of powder metallurgy (PM) parts, which are dominated primarily by iron and copper powders. This article reviews the chemical and pyrotechnics applications of ferrous and nonferrous powders. It describes the characteristics of iron powder used in oxygen scavengers and chemical reactive warmers and heaters. Metal powders used as fuels in solid propellants, pyrotechnic devices, explosives, and similar applications are reviewed. Atomized aluminum, magnesium, tungsten, and zirconium powders are also discussed.

This article reviews analytical techniques that are most often used in plastic component failure analysis. The description of the techniques is intended to familiarize the reader with the general principles and benefits of the methodologies, namely Fourier transform infrared spectroscopy, energy-dispersive x-ray spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The article describes the methods for molecular weight assessment and mechanical testing to evaluate plastics and polymers. The descriptions of the analytical techniques are supplemented by a series of case studies to illustrate the significance of each method. The case studies also include pertinent visual examination results and the corresponding images that aided in the characterization of the failures.