Argentum Solutions Inc. - Sterling Guidance on Corrosion and Materials Degradation

Argentum Solutions, Inc.

Sterling guidance on corrosion and materials degradation

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TUTORIAL ON ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY

David C. Silverman

Table of Contents

Overview of Tutorial
Overview of EIS
Analysis Using Simple Circuits
Constant Phase Element
Corrosion Rate Estimation

Two Capacitive Relaxation Time Constants
Critical Criteria for Proper Spectra
Diffusion Impedance
Pseudoinductance

Overview of Tutorial

Electrochemical impedance spectroscopy (also known as: AC impedance or the electrochemical impedance technique) is an electrochemical technique that has gained wide acceptance for corrosion rate measurement, corrosion research, corrosion monitoring, and corrosion quality assurance. Some of the documented areas of application are:

Rapid estimation of corrosion rates (30 min to 24 hr after immersion)
Estimation of corrosion rates in slowly changing systems (as long as stability is not compromised)
Estimation of low corrosion or contamination rates (e.g. less than 0.01 mpy)
Rapid assessment of inhibitors in various applications
Corrosion rate estimation in low conductivity media (e.g. organic fluids, soil, and concrete)
Evaluation of corrosion under coatings and quality assurance of coatings

This tutorial concentrates on selected areas pertaining to analysis of electrochemical impedance spectra as shown in the Table of Contents above. The tutorial makes the assumption that the reader understands how impedance spectra are generated, has possibly generated such spectra, and has been exposed to some of the methods commonly used to relate the spectra to corrosion rates and mechanisms.
To go to a particular topic, click on the active word colored in blue. Clicking on the word "top" at the end of each section will return to the table of contents at the beginning of the tutorial.

Next Page: Overview of EIS

Return to Table of Contents

David C. Silverman, Ph.D. - Primary Consultant
E-Mail:     dcsilverman@argentumsolutions.com
Phone:     314-576-3586
Fax:         314-754-9825
Address:   The Argentum House
                14314 Strawbridge Ct.
                Chesterfield, MO 63017