Overview
CEN ISO/TR 5602:2022 (adopted from ISO/TR 5602:2021) is a technical report that documents common sources of error in electrochemical impedance spectroscopy (EIS) when investigating coatings and other materials. The report covers the full workflow - from sample and measuring-cell set‑up through measurement, parameter selection and data evaluation - and explains how experimental and instrumental factors can bias EIS results. The document is informative (not normative) and explicitly notes that the listed errors are not exhaustive.
Key topics
The report organizes practical error sources and mitigation guidance across these technical areas:
- Measuring-cell make‑up
- Surface roughness, O‑ring and exposed area definition, optically detectable and non‑detectable leaks
- Reference and counter electrode positioning, shielding, bleeding, poisoning, gas inclusion
- Electronics and shielding
- Use of Faraday cages, cable effects (shielding, extension, breaks), contact resistances, inductance
- Power‑supply noise, insufficient signal‑to‑noise ratio, peripheral-device interference
- Parameter selection and measurement limits
- Amplitude selection, frequency range limits, switching, open‑lead tests and dummy cells
- Non‑stationary conditions
- Temperature fluctuations, changing electrolyte conductivity, swelling, drifting open‑circuit potential (OCP), corroding electrodes, gas formation
- Data modelling and interpretation
- Choice and limitations of equivalent circuits (constant phase element, Warburg impedance)
- Measurement uncertainty, plausibility checks and practical interpretation for coating systems
- Data presentation and annexes
- Guidance on presenting results and annexes with capacitance calculations, double‑layer effects and corrosion‑related apparent capacitances
Applications and who uses it
This report is intended for professionals involved in EIS testing of coatings and materials, including:
- Corrosion scientists and electrochemists
- Coatings R&D and formulation engineers
- Quality‑control and test laboratories
- Materials scientists and surface analysts
- EIS instrument manufacturers and test-cell designers
Practical uses include troubleshooting inconsistent EIS data, designing robust measuring cells, defining measurement protocols (amplitude/frequency), improving signal‑to‑noise, selecting appropriate equivalent circuits, and assessing barrier properties and coating performance with greater confidence.
Related standards
- ISO/TR 5602:2021 (original ISO text)
- ISO 16773 series (EIS measurement methodology and dummy‑cell guidance)
- CEN/TC 139 and ISO/TC 35 background for paints and varnishes
Keywords: electrochemical impedance spectroscopy, EIS, coatings, sources of error, measuring cell, equivalent circuit, frequency range, signal‑to‑noise, corrosion, measurement uncertainty.