This article describes the analytical methods for analyzing surfaces for corrosion and corrosion inhibition processes as well as failure analysis based on surface structure and chemical identity and composition. The principles and applications of the surface-structure analysis techniques, namely, optical microscopy, scanning electron microscopy, scanning tunneling microscopy, and atomic force microscopy, are reviewed. The article discusses the principles and applications of chemical identity and composition analysis techniques. These techniques include the energy dispersive X-ray spectroscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy, ion scattering spectroscopy, reflectance Fourier transform infrared absorption spectroscopy, Raman and surface enhanced Raman spectroscopy, and extended X-ray absorption fine structure analysis.

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.

Electron probe microanalysis (EPMA) makes it possible to combine structural and compositional analysis in one operation. This article describes the basic concepts of microanalysis and the processing of EPMA that involves the measurement of the characteristic X-rays emitted from a microscopic part of a solid specimen bombarded by a beam of accelerated electrons. It provides information on the various aspects of energy-dispersive spectrometry (EDS) and wavelength-dispersive spectrometry (WDS), and elucidates the qualitative analysis of the major constituents of EDS and WDS. The article includes information on the analog and digital compositional mapping of elemental distribution, and describes the strengths and weaknesses of WDS and EDS spectrometers in X-ray mapping. It also outlines the application of EPMA for solving various problems in materials science.

This article focuses on the visual or macroscopic examination of damaged materials and interpretation of damage and fracture features. Analytical tools available for evaluations of corrosion and wear damage features include energy dispersive spectroscopy, electron probe microanalysis, Auger electron spectroscopy, secondary ion mass spectroscopy, and X-ray powder diffraction. The article discusses the analysis and interpretation of base material composition and microstructures. Preparation and examination of metallographic specimens in failure analysis are also discussed. The article concludes with a review of the evaluation of polymers and ceramic materials in failure analysis.

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.

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.

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.