Overview
EN ISO 16773-2:2016 - Electrochemical impedance spectroscopy (EIS) on coated and uncoated metallic specimens - Part 2: Collection of data - is a CEN-endorsed ISO guideline for acquiring reliable EIS data. The standard focuses on high-impedance systems (intact coatings with impedance greater than 10^9 Ω·cm²) but is also applicable to lower-impedance measurements. It defines best practices for experimental setup, validation, measurement execution and presentation of EIS data for coated and uncoated metallic specimens. This part does not cover data interpretation.
Key topics and technical requirements
- Instrumental set-up: recommendations and common pitfalls for electrodes, cell geometry, grounding and shielding to minimize noise and measurement artefacts.
- Electrochemical cell components: guidance on electrode selection, exposed area determination and electrolyte considerations to ensure reproducible conditions.
- Data validation: procedures for checking measurement range, signal accuracy and confidence tests (including use of interlaboratory test cells and error/accuracy estimates).
- Measurement procedure: specimen preconditioning, environmental control, conditioning potential and time, and procedural steps for repeatable EIS acquisition.
- Instrumental parameters: guidance on frequency spectra, data point spacing, perturbation amplitude, DC potential control, current range and data averaging to optimize results, especially for high-impedance coatings.
- Data presentation: standard methods for reporting EIS results including Bode plots, Nyquist plots, and an exchange file format for data interoperability.
- Reporting: mandatory elements of the test report and annexes (e.g., determination of maximum measurable impedance and exposed area considerations).
Practical applications
- Quality control and acceptance testing of protective coatings and varnishes.
- Laboratory and field evaluation of coating barrier performance and deterioration.
- Corrosion testing for metals and alloys where EIS is used to monitor coating integrity.
- R&D for coating formulation, accelerated aging studies and evaluation of surface treatments.
- Establishing repeatable measurement protocols for high-impedance specimens.
Who should use this standard
- Coating and corrosion laboratories performing EIS measurements.
- Materials scientists and electrochemists conducting barrier or degradation studies.
- Quality assurance engineers in surface treatment and protective coatings industries.
- Manufacturers of EIS instrumentation and test cells.
- Standards committees and technical auditors involved in test method harmonization.
Related standards
- ISO 16773-1 - Terms and definitions for EIS on coated/uncoated specimens
- ISO 16773-3 - Processing and analysis of data from dummy cells
- ISO 16773-4 - Examples of spectra for polymer-coated and uncoated specimens
- ISO/TR 16208 - Additional guidance for uncoated samples
Keywords: Electrochemical impedance spectroscopy, EIS, EN ISO 16773-2:2016, high-impedance coatings, coated metallic specimens, data collection, Bode plot, Nyquist plot, coating testing.