engleski

Advances in application of electrochemical methods for in-field paint coatings quality assurance and control

Long-term corrosion protection may be achieved by a coating system that requires little or no maintenance, or by a system that requires several major maintenance operations during the structure’s design lifetime. It has been shown that electrochemical impedance spectroscopy (EIS) is a suitable method for coating lifetime prediction, generating invaluable input for making informed decisions within the scope of coating quality assurance system related to coating choice and its lifecycle economics. EIS is equally successfully applied in field for performance rating of new coatings and coatings that have spent time in service. Coating resistance, capacitance, water uptake and dielectric constant may be recorded as functions of time and indicate probable premature coating failure before it can be visually observed. When used, on reference samples and multiple positions on a structure, the technique can also discriminate between low quality coating and improper workmanship. Early detection of corrosion under coating is observed as significant drop in coating impedance and appearance of additional time constant representing steel/coating pores interface. Recent technical advances originating from Research Laboratory for Corrosion Engineering and Surface Protection of FKIT, Zagreb, that led towards method simplification for use in laboratory and in field, will be presented, alongside with the examples of successful application. Reference will be made to state-of- the-art and prospects of wide-spreading the use of electrochemical methods for paint coating QA and QC.

corrosion ; coating ; electrochemical impedance spectroscopy

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