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.

This article provides an overview of the most common micro-analytical technique in the failure analysis laboratory: energy dispersive X-ray spectroscopy (EDS). It discusses the general characteristics, advantages, and disadvantages of some of the X-ray detectors attached to the scanning electron microscope chamber including the lithium-drifted EDS detector, silicon drift detector (SDD), and wavelength dispersive X-ray detector. The article then provides information on qualitative and quantitative X-ray analysis programs followed by a discussion on EDS elemental mapping. The discussion includes a comparison of scanning transmission electron microscope-EDS elemental mapping and mapping with an SDD. A brief section is devoted to the discussion on the artifacts that occur during X-ray mapping.

There are several analytical methods available that can be used in-line on whole wafers as well as off-line on de-processed products that are returned from the field. These techniques are surface analytical techniques that can be used to characterize the bulk of the material. The main six methods used in semiconductor industry are: Auger spectroscopy, dynamic secondary ion mass spectroscopy, time of flight static secondary ion mass spectroscopy (ToF-SIMS), X-ray photoelectron spectroscopy, scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscope-EDX. This review specifically addresses ToF-SIMS and describes some typical examples of the application of Auger and SEM-EDX.

The ultimate goal of the failure analysis process is to find physical evidence that can identify the root cause of the failure. Transmission electron microscopy (TEM) has emerged as a powerful tool to characterize subtle defects. This article discusses the sample preparation procedures based on focused ion beam milling used for TEM sample preparation. It describes the principles behind commonly used imaging modes in semiconductor failure analysis and how these operation modes can be utilized to selectively maximize signal from specific beam-specimen interactions to generate useful information about the defect. Various elemental analysis techniques, namely energy dispersive spectroscopy, electron energy loss spectroscopy, and energy-filtered TEM, are described using examples encountered in failure analysis. The origin of different image contrast mechanisms, their interpretation, and analytical techniques for composition analysis are discussed. The article also provides information on the use of off-axis electron holography technique in failure analysis.

This chapter describes some of the most effective tools for investigating boiler tube failures, including scanning electron microscopy, optical emission spectroscopy, atomic absorption spectroscopy, x-ray fluorescence spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. It explains how the tools work and what they reveal. It also covers the topic of image analysis and its application in the measurement of grain size, phase/volume fraction, delta ferrite and retained austenite, inclusion rating, depth of carburization/decarburization, scale thickness, pearlite banding, microhardness, and hardness profiles. The chapter concludes with a brief discussion on the effect of scaling and deposition and how to measure it.

This chapter elucidates the indispensable role of characterization in the development of cold-sprayed coatings and illustrates some of the common processes used during coatings development. Emphasis is placed on the advanced microstructural characterization techniques that are used in high-pressure cold spray coating characterization, including residual-stress characterization. The chapter includes some preliminary screening of tool hardness and bond adhesion strength, as well as a distinction between surface and bulk characterization techniques and their importance for cold spray coatings. The techniques covered are optical microscopy, X-Ray diffraction, scanning electron microscopy, focused ion beam machining, electron probe microanalysis, transmission electron microscopy, and electron backscattered diffraction. The techniques also include electron channeling contrast imaging, X-Ray photoelectron spectroscopy, X-ray fluorescence, Auger electron spectroscopy, Raman spectroscopy, oxygen analysis, and nanoindentation.

The overall chemical composition of metals and alloys is most commonly determined by x-ray fluorescence (XRF) and optical emission spectroscopy (OES). High-temperature combustion and inert gas fusion methods are typically used to analyze dissolved gases (oxygen, nitrogen, and hydrogen) and, in some cases, carbon and sulfur in metals. This chapter discusses the operating principles of XRF, OES, combustion and inert gas fusion analysis, surface analysis, and scanning auger microprobe analysis. The details of equipment set-up used for chemical composition analysis as well as the capabilities of related techniques of these methods are also covered.

This chapter describes the procedures and processes used to chemically analyze beryllium samples. It discusses gravimetric, volumetric, colorimetric, and fluorometric techniques, radiochemical separation and assay, and the use of emission spectrometry and polarographic methods.

During a major servicing of an aircraft, cracks were found in the bottom wing root fitting. Based on dye penetrant inspection and the results of SEM fractography and chemical analysis, investigators concluded that the cracks were due to stress corrosion. They also recommended an inspection of all other aircraft with similar fittings and the consideration of alternate materials that are less prone to stress-corrosion cracking.

This chapter discusses the failure of a compressor blade in an aircraft engine and explains how investigators determined the cause. Based on visual examination and the results of SEM fractography and chemical analysis, it was concluded that blade failed due to fatigue fracture originating from nonmetallic inclusions in the blade root.

Several hydraulic pumps that failed in service on a particular type of aircraft were received for analysis. Hydraulic testing was not an option, so the pumps were disassembled and their plungers and cylinders were cleaned and examined. Based on their observations, investigators concluded that cavitation erosion damaged the plungers, causing them to seize.

A driven gear in the gear box of an aircraft engine fractured after a 40 h test run. The driving gear and gear shaft were also damaged. Based on the results of fractography, chemical analysis, metallography, and hardness testing, the fracture was caused by a fatigue crack initiating at the corner of the inner rim near an inclusion. The report recommends the use of a cleaner material and more carefully controlling case hardening process.

One of the rotor bearings in an electric motor failed, producing excessive vibrate. The bearing was removed and disassembled, revealing craters and bruises on the inner ring raceway and balls along with evidence of melting and burning of metal. Scanning electron microscopy revealed metal particles near the craters, and energy-dispersive x-ray analysis showed that slivers recovered from the grease had the same composition as the bearing raceway and balls. Based on these observations, it was concluded that the bearing failed due to electrostatic discharge, which would have led to seizure if it continued. The report recommends the use of electrically conductive grease and proper grounding practices.

This article focuses on characterization techniques used for analyzing the physical behavior and chemical composition of thermoset resins, namely chromatography and infrared spectroscopy. The main purpose is to give sufficient detail to permit the reader understand a particular test technique and its value to the thermoset resin field. Epoxy resins are emphasized in the examples because they dominate the airframe and aerospace industries. The article also provides information on two categories of characterization of the processing behavior of thermoset. The first studies the thermal properties of reactive thermoset systems, while the second utilizes these thermal characteristics as the basis for monitoring and control during processing.

This article introduces procedures an engineer or materials scientist can use to investigate failures. It provides a brief survey of polymer systems and key properties that need to be measured during failure analysis. The article begins with an overview of the problem-solving approach pertinent to structure analysis. This is followed by a review of the characterization of plastics by infrared and nuclear magnetic resonance spectroscopy. The article then provides information on the distribution of molecular weight of an engineering plastic. It further discusses the methods used in thermal analysis, namely differential thermal analysis, thermogravimetric analysis, thermal-mechanical analysis, and dynamic mechanical analysis. The following sections provide details on X-ray diffraction for analyzing crystalline phases and on a minimal scheme for polymer analysis and characterization to assist the design engineer. The article ends with a discussion on the thermal-analytical scheme for analyzing the milligram quantities of polymer samples.

This article reviews various analytical techniques most commonly used in plastic component failure analysis. The description of the techniques is intended to make the reader familiar with the general principles and benefits of the methodologies. The descriptions of the analytical techniques are supplemented by a series of case studies that include pertinent visual examination results and the corresponding images that aided in the characterization of the failures. The techniques covered include Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, thermomechanical analysis, and dynamic mechanical analysis. The article also discusses various analytical methods used to characterize the molecular weight distribution of a polymeric material. It provides information on a wide range of mechanical tests that are available to evaluate plastics and polymers, covering the various considerations in the selection and use of test methods.

This article covers common techniques for surface characterization, including the modern scanning electron microscopy and methods for the chemical characterization of surfaces by Auger electron spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. The principles of surface analysis and some of the applications of the technique in polymer failure studies are also provided.

Process gas control for plasma (ion) nitriding is a matter of estimating the flows necessary to accomplish the required surface metallurgy. This chapter reviews several studies aimed at better understanding process gas control in plasma nitriding and its influence on compound zone formation. Emphasis is placed on the effect of sputtering on the kinetics of compound zone formation. The discussion covers the processes involved in process gas control analysis by photo spectrometry and mass spectrometry and the difficulties associated with gas analysis.