Paints and varnishes — Electrochemical measurement of the protection provided to steel by paint coatings — Current interrupter (CI) technique, relaxation voltammetry (RV) technique and DC transient (DCT) measurements

1 Scope

This International Standard specifies the procedure for evaluation of the experimental set-up of electrochemical

measurements on high-impedance coated samples using methods that are based on the current interrupter

(CI) technique, relaxation voltammetry (RV) or DC transient (DCT) measurements.

It provides specific definitions and guidance on optimizing the collection of CI, RV and DCT data from highimpedance

systems. High impedance in the context of intact coatings refers to systems with an impedance

greater than 109 Ω/cm2. This does not preclude measurements on systems with lower impedance. This

International Standard deals in particular with:

— instrumental set-up: requirements and shortcomings;

— data validation: checking the measurement range and the accuracy of the data;

— performing CI, RV, DCT measurements: specimen considerations and instrumental parameters;

— the experimental results: different methods of presenting CI, RV and DCT data.

Following the recommendations should ensure the acquisition of CI, RV and DCT data that can be used to study the

performance of the specimen. This International Standard does not give guidelines for the interpretation o