Search Results for electrochemical impedance spectroscopy

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 provides an overview of common analytical tools used as part of the process of providing practical information regarding the causes of a coating problem or failure. The common analytical tools include Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy-energy dispersive X-ray spectroscopy, chromatography, and electrochemical impedance spectroscopy. Test cabinets and standard test environments for laboratory analysis are reviewed. The article describes non-standard simulation testing and case studies of simulated environments for coating failure analysis.

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.

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.

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.

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 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.

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.

Corrosion of metallic materials is governed by electrochemical kinetics, so that the general concepts developed for studying electrochemical reaction mechanisms may be applied to corrosion. This article presents the fundamental aspects of electrode kinetics. The processes of charge transfer taking place at the electrode interface within the double layer and of mass transport at the vicinity of the electrode surface are discussed. The article describes the corrosion processes, which involve anodic and cathodic reactions at specific electrode sites. Some experimental methods for devising a reliable reaction model are detailed. The article explains some reaction mechanisms for cathodic and anodic processes to illustrate the great variety of reaction mechanisms occurring at the electrode interface.

Corrosion monitoring is important in the operation of modern industrial plants and in the use and maintenance of expensive assets such as bridges and aircrafts, because the damage caused by corrosion and the rate of the deterioration can be huge and the risks devastating. This article discusses the system considerations and installation techniques of different types of direct and indirect techniques in electrochemically based on-line corrosion monitoring process. It describes the importance of probe location and on-line corrosion monitoring techniques with examples.

A sacrificial coating applied to a steel substrate can add 20 years or more of life to the substrate, depending on its thickness and composition. Different techniques to apply sacrificial coatings offer various characteristics that contribute to corrosion resistance. This article discusses thermal spray, hotdipping, and electroplating processes used to apply coatings in steel structures. It describes the corrosion attributes of the resulting coatings and discusses the methods of protecting steel from corrosion using aluminum and zinc coatings.