What is ISO 16773-3 - EIS for paint with metallic specimens about?
ISO 16773 describes a procedure for the evaluation of protective anticorrosion coatings by using electrochemical impedance spectroscopy (EIS).
EIS is an electrochemical technique with applications in corrosion, biosensors, battery development, fuel cell development, paint characterization, sensor development, and physical electrochemistry. 
ISO 16773-3 deals with the procedure used for the evaluation of the experimental results obtained from dummy cells which simulate high-impedance coated samples and it gives acceptance criteria for the values obtained.
Based on the equivalent circuits described, ISO 16773-3 gives guidelines for the use of dummy cells to increase confidence in the test protocol, including making measurements, curve fitting and data presentation.
Note: Due to the nature of the measurements, investigations of high impedance coated samples are more susceptible to artefacts coming from electromagnetic interferences. Therefore, this part of ISO 16773 considers the aspects for measuring high-impedance samples by using appropriate dummy cells in a Faraday cage. However, most manufacturers offer complementary dummy cells in the low and medium impedance range. This allows checking the setup in the respective low impedance range.
Who is ISO 16773-3 - EIS for paint with metallic specimens for?
ISO 16773-3 on ‘EIS for paint with metallic specimens’ is useful for:
- Paint and varnish manufacturers
- Research and testing laboratories
- Researchers dealing with biosensors and nanoparticles
- Manufacturers of Pathological Diagnostic Equipment
- Product development teams
- Quality control teams
Why should you use ISO 16773-3 - EIS for paint with metallic specimens?
When paint coatings degrade with time, water may penetrate into the coating and form a new liquid/metal interface under the coating. Corrosion phenomena can occur at this new interface. The impedance of coated metals needs to be studied.
EIS involves the application of a sinusoidal electrochemical perturbation (potential or current) to the sample that covers a wide range of frequencies.  This multi-frequency excitation allows the measurement of:
- Several electrochemical reactions that take place at different rates
- The capacitance of the electrode
ISO 16773-3 discusses using dummy cells, apart from the general procedure and data analysis. Using ISO 16773-3 guidelines, you would be able to perform EIS on coated and uncoated metallic specimens; and process and analyse the data from dummy cells, so that you can provide your customers with suitable products and quality results.
What’s changed since the last update?
BS EN ISO 16773-3:2016 supersedes BS EN ISO 16773-3:2009. BS EN ISO 16773-3:2016 includes some technical changes with respect to BS EN ISO 16773-3:2009. These include:
- The introductory element of the title, paints and varnishes, has been omitted, because the scope is broadened to include metals and alloys and the main element of the title has been changed to: Electrochemical impedance spectroscopy (EIS) on coated and uncoated metallic specimens
- A reference to ISO/TR 16208 for dummy cells with low impedance values (10 Ω to 1 000 Ω) has been added
- A reference to ASTM G106 for the precision data of low impedance measurements has been added
- A test report has been added
