Online Course:
Measure Corrosion by Electrochemical Impedance Spectroscopy
A practical approach to using electrochemical impedance spectroscopy, or EIS, for corrosion measurement and analysis.
Course Content & Lectures Preview
- Introduction to Section 1 (2:09)
- What is Electrochemical Impedance Spectroscopy? (4:31)
- Understanding the Corroding Surface (9:33)
- Resistive response of a simple corroding surface and Stern-Geary equation (5:23)
- Double layer capacitance (3:21)
- Electrolyte resistance (3:43)
- Alternating current (AC) signals (2:29)
- Understanding the concept of impedance (8:23)
- Connecting impedances in series and in parallel (7:13)
- Summary of Section 1 (2:52)
- Section 1 Quiz
- Introduction to Section 2 (2:05)
- Measuring the EIS spectrum (10:03)
- Interactive App: Simulate EIS signal (0:36)
- Effects of polarisation resistance, electrolyte resistance and double layer capacitance (6:06)
- Interactive App: Simulate EIS spectrum (0:26)
- Interactive App: Simulate EIS spectrum (multi-curve) (0:25)
- Impact of frequency range on resolvable parameters (5:49)
- Impact of surface layers on EIS response (14:14)
- Interactive App: Effect of parameters on EIS for surface with layer (0:55)
- Effect of area and relative area on EIS spectra (11:57)
- EIS response of a surface supporting a coating with defects (8:09)
- Interactive App: Effect of relative area of regions with different behaviour. (0:46)
- Interactive App: Effect of relative area of regions (multi curve) (0:24)
- Summary of Section 2 (1:22)
- Introduction to Section 3 (1:56)
- Measuring EIS at the corrosion potential (4:13)
- Influence of signal amplitude on the EIS measurement (11:40)
- Interactive App: Current response near corrosion potential (0:23)
- Impact of measurement frequency range on measurement time (12:40)
- Interactive App: Impact of parameters on measurement time (0:26)
- Charge passed during EIS measurements (6:22)
- Interactive App: Thickness of oxidised material (0:42)
- Requirement of stationarity and noise-related issues (9:18)
- S3 Summary (1:51)
- Introduction to Section 4 (2:04)
- How fitting works (12:56)
- Interactive App: Fitting process and error surface
- Characteristic responses of individual equivalent circuit components (8:45)
- Interactive App: Individual components impedance (0:28)
- Key features in EIS spectra (13:44)
- Interactive App: Response of circuit containing a CPE
- Interactive App: Response of circuit containing CPE and Warburg short. (0:22)
- Constructing an equivalent circuit model (16:28)
- Practical example of fitting EIS data (16:36)
- Interactive App: Fitting Example
- Summary of Section 4 (1:57)
Course Description
In this course, we will take a practical approach to understanding and using electrochemical impedance spectroscopy (EIS) for corrosion measurement and analysis. We will begin by covering the basics of EIS, discussing essential concepts like impedance, alternating current signals, and corrosion surface phenomena, all aimed at making EIS accessible and straightforward for everyone, and we will finish with a practical example of fitting a complex EIS spectrum.
In Section 1, we will learn about the fundamentals of corrosion and impedance in electrochemical systems, building the foundation for understanding how and why EIS is applied to corrosion studies. In Section 2 we will look at how the processes occurring on the surface impact on the EIS responses, considering key factors like polarization resistance, double layer capacitance, and the impact of surface coatings on the EIS response.
In Section 3, we will focus on practical considerations for measuring EIS spectra. We will discuss critical topics such as the selection of signal amplitude, the measurement frequency range, and the importance of stationarity to obtain reliable results. Finally, in Section 4, we will learn how to interpret EIS spectra using equivalent circuit models, exploring characteristic responses and fitting techniques to extract valuable information from the data.
By the end of the course, we will have the knowledge and skills needed to confidently measure, model, and interpret EIS data for effective corrosion analysis.