Low-energy electron diffraction (LEED) is a technique for investigating the crystallography of surfaces and overlayers adsorbed on surfaces. This article provides a brief account of LEED, covering the principles and measurements of diffraction from surfaces. Some of the processes involved in sample preparation are described. In addition, the article discusses the limitations of surface-sensitive electron diffraction and the applications of LEED with examples.

This article is a brief account of low-energy ion-scattering spectroscopy (LEIS) for determining the atomic structure of solid surfaces. It begins with a description of the general principles of LEIS. This is followed by a section providing information on the equipment used for LEIS. Various steps involved in the sample preparation, calibration, and data analysis are then discussed. The article concludes with a section on the applications and interpretation of LEIS in material analysis, including discussion on surface structural analysis, layer-by-layer (Frank-van der Merwe) growth, and low-energy atom-scattering spectroscopy.

This article focuses on transport phenomena and modeling approaches that are specific to vapor-phase processes (VPP). It discusses the VPP for the synthesis of materials. The article reviews the basic notions of molecular collisions and gas flows, and presents transport equations. It describes the modeling of vapor-surface interactions and kinetics of hetereogeneous processes as well as the modeling and kinetics of homogenous reactions in chemical vapor deposition (CVD). The article provides information on the various stages of developing models for numerical simulation of the transport phenomena in continuous media and transition regime flows of VPP. It explains the methods used for molecular modeling in computational materials science. The article also presents examples that illustrate multiscale simulations of CVD or PVD processes and examples that focus on sputtering deposition and reactive or ion beam etching.

Thermomechanical analysis (TMA) is a thermal analysis technique in which the length of a specimen is precisely measured versus temperature and time as the specimen is subjected to controlled heating and cooling. This article discusses the various factors and processes involved in TMA. The discussion covers the general principles, equipment used, specimen preparation process, calibration conditions, data analysis steps, and examples of the applications and interpretation of TMA.

Ion-beam-assisted deposition (IBAD) refers to the process wherein evaporated atoms produced by physical vapor deposition are simultaneously struck by an independently generated flux of ions. This article discusses the energy utilization of this process. It describes the physical and chemical processes occurring at the film-vacuum interface during IBAD and dual-ion-beam sputtering with illustrations. The article also reviews the methods used for large-area, high-volume implementation of IBAD and the modes of film formation for IBAD. It contains a table that presents information on deposition and synthesis of inorganic compounds by IBAD and concludes with a discussion on the improved coating properties, advantages, limitations, and applications of IBAD.

This article provides a detailed account of the basic concepts of Rutherford backscattering spectrometry (RBS). It begins with a description of the principles of RBS, as well as the effect of channeling in conjunction with backscattering measurements and the effect of energy loss under this condition. This is followed by a section on equipment used in RBS analysis. Channel-energy conversion, energy-depth conversion, and separation of the dechanneling background are then discussed as the main steps of RBS data analysis. The article also discusses the applications of RBS—including composition of bulk samples, thin-film composition and layer thickness, impurity profiles, damage depth profile, and surface peak—as well as the various codes developed to simulate it.

Ultrasonic inspection is a nondestructive method in which beams of high-frequency acoustic energy are introduced into a material to detect surface and subsurface flaws, to measure the thickness of the material, and to measure the distance to a flaw. This article provides a detailed account of ultrasonic flaw detectors, including ultrasonic transducers and types of search units and couplants. The article describes pulse-echo and transmission inspection methods and data interpretation. The general characteristics of ultrasonic waves and the factors influencing ultrasonic inspection are also addressed. The article concludes with a review of the advantages and disadvantages of ultrasonic inspection compared with other methods applications of the technique.

This article is intended to provide the reader with a good understanding of the underlying science, technology, and the most common applications of focused ion beam (FIB) instruments. It begins with a survey of the various types of FIB instruments and their configurations, discusses the essential components, and explains their function only to the extent that it helps the operator obtain the desired results. An explanation of how the components of ion optical column shape and steer the ion beam to the desired target locations is then provided. The article also reviews the many diverse accessories and options that enable the instrument to realize its full potential across all of the varied applications. This is followed by a detailed analysis of the physical processes associated with the ion beam interacting with the sample. Finally, a complete survey of the most prominent FIB applications is presented.

Electron beam melting includes melting, refining, and conversion processes for metals and alloys. This article describes the electron beam melting process, as well as the principles, equipment, and process considerations of drip melting and cold hearth melting process.

Ultrasonic inspection is a family of nondestructive methods in which beams of high-frequency mechanical waves are introduced into materials, using transducers, for the detection and characterization of both surface and subsurface anomalies and flaws in the material. This article describes the basic equipment in ultrasonic inspection systems, and lists the advantages and disadvantages of these systems. It discusses the applications of ultrasonic inspection and also the general characteristics of ultrasonic waves in terms of wave propagation, longitudinal waves, transverse waves, surface waves, and lamb waves. The article reviews the major variables in ultrasonic inspection, including frequency, acoustic impedance, angle of incidence, and beam intensity. It discusses the attenuation of ultrasonic beams and provides information on the pulse-echo and transmission methods for implementing ultrasonic inspection.

Microstructural analysis is the combined characterization of the morphology, elemental composition, and crystallography of microstructural features through the use of a microscope. This article reviews three types of the most commonly used electron microscopies in metallurgical studies, namely scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy. It briefly describes the operating principles, instrumentation which includes energy dispersive X-ray detectors, spatial resolution, typical use of the techniques, elemental analysis detection threshold and precision, limitations, sample requirements, and the capabilities of related techniques.

Computed tomography (CT) is an imaging technique that generates a three-dimensional (3-D) volumetric image of a test piece. This article illustrates the basic principles of CT and provides information on the types, applications, and capabilities of CT systems. A comparison of performance characteristics for film radiography, real-time radiography, and X-ray computed tomography is presented in a table. A functional block diagram of a typical computed tomography system is provided. The article discusses CT scanning geometry that is used to acquire the necessary transmission data. It also provides information on digital radiography, image processing and analysis, dual-energy imaging, and partial angle imaging, of a CT system.

Ion implantation involves the bombardment of a solid material with medium-to-high-energy ionized atoms and offers the ability to alloy virtually any elemental species into the near-surface region of any substrate. This article describes the fundamentals of the ion implantation process and discusses the advantages, limitations, and applications of ion implantation. It also reviews a typical medium current semiconductor implanter adapted for implantation of metals with the aid of illustrations.

This article is a detailed account of the principles of electron-excited X-ray microanalysis. It begins by discussing the physical basis of electron-excited X-ray microanalysis and the advantages and limitations of energy dispersive spectrometry (EDS) and wavelength dispersive spectrometry for electron probe microanalysis. Key concepts for performing qualitative analysis and quantitative analysis by electron-excited X-ray spectrometry are then presented. Several sources that lead to measurement uncertainties in the k-ratio/matrix corrections protocol are provided, along with the significance of the raw analytical total. Sections on accuracy of the standards-based k-ratio/matrix corrections protocol with EDS and processes of analysis when severe peak overlap occurs are also included. The article provides information on low-atomic-number elements, iterative qualitative-quantitative analysis for complex compositions, and significance of standardless analysis in the EDS software. It ends with a section on the processes involved in elemental mapping for major and minor constituents.

X-ray spectroscopy is generally accepted as the most useful ancillary technique that can be added to any scanning electron microscope (SEM), even to the point of being considered a necessity by most operators. While “stand-alone” x-ray detection systems are used less frequently in failure analysis than the more exact instrumentation employed in SEMs, the technology is advancing and is worthy of note due to its capability for nondestructive analysis and application in the field. This article begins with information on the basis of the x-ray signal. This is followed by information on the operating principles and applications of detectors for x-ray spectroscopy, namely energy-dispersive spectrometers, wavelength-dispersive spectrometers, and handheld x-ray fluorescence systems. The processes involved in x-ray analysis in the SEM and handheld x-ray fluorescence analysis are then covered. The article ends with a discussion on the applications of x-ray spectroscopy in failure analysis.

This article focuses on the modes of operation, physical basis, sample requirements, properties characterized, advantages, and limitations of common characterization methods that are used to evaluate the physical morphology and chemical properties of component surfaces for medical devices. The methods include light microscopy, scanning electron microscopy, atomic force microscopy, energy-dispersive x-ray spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy.

This article describes testing and characterization methods of ceramics for chemical analysis, phase analysis, microstructural analysis, macroscopic property characterization, strength and proof testing, thermophysical property testing, and nondestructive evaluation techniques. Chemical analysis is carried out by X-ray fluorescence spectrometry, atomic absorption spectrophotometry, and plasma-emission spectrophotometry. Phase analysis is done by X-ray diffraction, spectroscopic methods, thermal analysis, and quantitative analysis. Techniques used for microstructural analysis include reflected light microscopy using polarized light, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis of X-rays, and wavelength dispersive analysis of X-rays. Macroscopic property characterization involves measurement of porosity, density, and surface area. The article describes testing methods such as room and high-temperature strength test methods, proof testing, fracture toughness measurement, and hardness and wear testing. It also explains methods for determining thermal expansion, thermal conductivity, heat capacity, and emissivity of ceramics and glass and measurement of these properties as a function of temperature.

This article provides a detailed account of X-ray spectroscopy used for elemental identification and determination. It begins with an overview of the operating principles of X-ray fluorescence (XRF) spectrometer, as well as a comparison of the operating principles of wavelength-dispersive spectrometer (WDS) and energy-dispersive spectrometer (EDS). This is followed by a discussion on the mechanism and effects of X-ray radiation, X-ray emission, and X-ray absorption. The article then discusses components used, operation, and applications of WDS and EDS. Some of the factors and processes involved in sample preparation for XRF analysis are also included. The article further provides information on the practical procedure for and the applications of WDS and EDS qualitative and quantitative analyses.

This article illustrates the three techniques for producing glassy metals, namely, liquid phase quenching, atomic or molecular deposition, and external action technique. Devitrification of an amorphous alloy can proceed by several routes, including primary crystallization, eutectoid crystallization, and polymorphous crystallization. The article demonstrates a free-energy versus composition diagram that summarizes many of the devitrification routes. It provides a historical review of the corrosion behavior of fully amorphous and partially devitrified metallic glasses. The article describes the general corrosion behavior and localized corrosion behavior of transition metal-metal binary alloys, transition metal-metalloid alloys, and amorphous simple metal-transition metal-rare earth metal alloys. It concludes with a discussion on the environmentally induced fracture of glassy alloys, including hydrogen embrittlement and stress-corrosion cracking.

Low-alloy steels are used in a broad spectrum of applications. In some cases, corrosion resistance is a major factor in alloy selection; in other applications, it is only a minor consideration. This article reviews the applications of alloy steel products in four major industries, namely, oil and gas production, energy conversion systems, marine applications, and chemical processing. Emphasis is placed on the corrosion characteristics of the products, which are used in various applications of each industry.