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.

This article presents a detailed account of ion chromatography (IC). It begins by describing the principles of common separation modes in IC. This is followed by a section on the different modes of detection, namely suppressed conductivity detection, nonsuppressed conductivity detection, spectrophotometric detection, and electrochemical detection. Various separation modes in IC are then described. The article further provides information on various eluents species, analyte range, and sample preparation techniques in IC. It ends by providing information on the instrumentation and applications and future directions of IC.

A variety of electrochemical techniques are used to detect and monitor material deterioration in service or in the field. This article describes the static or direct current measurements in a number of applications, including buried pipelines and storage tanks. It reviews the electrochemical impedance spectroscopy and electrochemical noise measurements in a laboratory, especially for the inspection of coatings.

This article focuses on the methods that are being developed for detecting and monitoring corrosion: electrochemical methods, electromagnetic or sound wave methods, fiber-optic technology, fluorescence methods, and the Diffracto Sight method. It reviews the importance of data management and the Corrosion Expert System. It concludes with information on the simulation and modeling for incorporating the mechanisms of corrosion prevention into military hardware systems design and operation.

This article provides a discussion on the operation of various methods and sensors that have been used or have the potential to be used for on-line, real-time monitoring of localized corrosion. These include the electrochemical noise (ECN) method, nonelectrochemical methods, the galvanically coupled differential flow cell, galvanically coupled crevice cell, coupled multielectrode sensor, and electrochemical biofilm activity sensor.

This article provides a summary of the concepts discussed in the article under the section "Corrosion Testing and Evaluation" in ASM Handbook, Volume 13A: Corrosion: Fundamentals, Testing, and Protection. This section presents fundamental information on step-by-step instructions for techniques, examples of actual test data, and hints to help in interpretation. The topics covered include planning corrosion tests and evaluating results, laboratory corrosion testing, simulated service corrosion testing, in-service techniques for damage detection and monitoring, and evaluating forms of corrosion.

This article explores the use of the electrochemical and nonelectrochemical techniques for measuring the corrosion behavior of buried metals and the types of probes used. The electrical resistance technique is the main nonelectrochemical technique used for measuring corrosion rate. Electrochemical techniques discussed include linear polarization resistance, electrochemical noise, harmonic distortion analysis, electrochemical impedance spectroscopy, and hydrogen permeation. The principles of operation for the corrosion measuring techniques are described along with examples of their use in soils.

This article describes the criteria for selecting a corrosion-monitoring method used in industrial plants. It provides a detailed discussion on the design, advantages, and disadvantages of plant corrosion-testing program. The basic types of racks used to support and insulate the coupons are also discussed. The analysis of electrical-resistance probes, sentry holes, side-stream loop, electrochemical noise, hydrogen-probe, and process streams are used to monitor and estimate corrosion rates. The corrosion rates can also be estimated by ultrasonic thickness measurements, polarization-resistance measurements, corrosion potential measurements, and alternating current impedance measurements. Corrosion monitoring strategies, such as locations, data analysis, redundancy, and other issues, are discussed. The article concludes with information on the interpretation and reporting of corrosion testing.

This article addresses electrochemical methods for instantaneous rate determination and threshold determination as well as nonelectrochemical methods that can determine incremental or cumulative rates of corrosion. Electrochemical methods for the study of galvanic corrosion rates and localized corrosion and evaluation of corrosion rates under paints are also discussed. The article describes nonelectrochemical methods that can determine incremental or cumulative rates of corrosion. Methods presented include polarization methods, polarization resistance methods, electrochemical impedance methods, frequency modulation methods, electrochemical noise resistance, potential probe methods, cyclic potentiodynamic polarization methods, potentiostatic and galvanostatic methods, electrochemical noise (EN) methods, scratch-repassivation method, and electrochemical impedance spectroscopy (EIS) techniques. Gravimetric determination of mass loss, electrical-resistance methods, magnetic methods, quartz crystal microbalance method, solution analysis methods, and metrological methods are nonelectrochemical methods. The article presents an electrochemical test that examines the susceptibility of stainless steel alloys to intergranular corrosion.

This article describes various methods of electrochemical analysis, namely coulometry, electrogravimetry, voltammetry, electrometric titration, and nanometer electrochemistry. The discussion covers the general uses, sample requirements, application examples, advantages, and limitations of these methods. Some of the factors pertinent to electrochemical cells are also provided. In addition, the article provides information on various potentiometric membrane electrodes used to quantify numerous ionic and nonionic species.

Voltammetry is the study of the current voltage relationships observed when electroactive species in solution are subject to oxidation or reduction at electrodes under carefully controlled conditions. This article describes the basic principle of voltammetry performed using the dropping mercury electrode (polarography). It discusses the various methods of voltammetry, namely, linear sweep voltammetry, cyclic voltammetry, and stripping voltammetry that are carried out with different electrode material. The article also explores the modern instrumentation and developments achieved in voltammetry, and provides an outline of additional data, such as values of the formation, or stability, and constants of complexes formed by shifting the half-wave potential, which can be obtained by voltammetry. Additionally, the article provides a brief account of the applications of voltammetry.

This article reviews the fundamentals of electrochemical corrosion test methods. The features and requirements of the instrumentation needed for an electrochemical test are briefly discussed. The article provides a discussion on the various electrochemical techniques and tests available for laboratory studies of corrosion phenomena. The techniques and tests include no-applied-signal tests, small-signal polarization tests, large-signal polarization tests, scanning electrode techniques, and miscellaneous techniques.

Electrochemical machining (ECM) is the controlled removal of metal by anodic dissolution in an electrolytic cell in which the workpiece is the anode and the tool is the cathode. This article begins with a description of the ECM system and then discusses the primary variables that affect current density and the material removal rate in the ECM process. It reviews the various characteristics of electrolytes and considers tool material and design. It also provides an overview of the properties of the workpiece and defines the surface finish and accuracy of an electrochemically machined sample. The variety of work done by electrochemical machining is also exemplified in the article.

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.

Chromate conversion coatings (CCCs) are primarily used to improve adhesion of subsequently applied organic coatings or to impart corrosion resistance during atmospheric exposure. This article describes the factors that affect the formation of CCCs. It provides information on the processing sequence, morphology, composition, and properties of CCCs. The article discusses the electrochemical impedance spectroscopy approach used for evaluating conversion coatings. The test methods for various CCCs properties are also reviewed. The article examines the various coatings associated with chromate-free conversion. These include: titanium and zirconium fluorocomplexes; cerium-base, manganese-base, cobalt-base, and molybdate-base conversion coatings; hydrotalcite coatings; and organic coatings.

This article provides a clear but nonexhaustive description of the general principle of atomic emission, with a particular focus on instrumentation, and summarizes the main characteristics of the inductively coupled plasma optical emission spectrometer technique. Basic atomic theory as well as the instrument characteristics and their influence on the instrument performances are presented. The advantages, drawbacks, and developments of this technique are discussed, and, finally, alternative techniques and examples of applications are provided.

This article discusses the various categories of nontraditional machining processes that are subdivided according to the form of energy being harnessed. These include mechanical, electrical, thermal, and chemical methods.

Corrosion resulting from the presence and activities of microbes on metals and metal alloys is generally referred to as microbiologically influenced corrosion (MIC). This article describes the biofilm formation and structure and microbial processes influencing corrosion. It also discusses the electrochemical techniques used to study and monitor MIC and presents examples of their applications to MIC.

This article focuses on the different parameters that influence the pitting corrosion of passive metals. The parameters are environment, metal composition, potential, temperature, surface condition, alloy composition, stochastic nature of the processes, and inhibitors. In addition, the article provides a detailed discussion on the various stages of pitting. These include passive film breakdown, metastable pitting, pit growth, and pit stifling or death.