Investigation of Protective Behavior of Different Cathodic Electrocoatings Using Different Anti-Corrosive Tests (Modified AC/DC/AC Test, EIS and Salt Spray)

Lajevardi Esfahani, S.; Ranjbar, Z.; Rastegar, S.

Investigation of Protective Behavior of Different Cathodic Electrocoatings Using Different Anti-Corrosive Tests (Modified AC/DC/AC Test, EIS and Salt Spray)

Authors

¹ Department of Surface Coatings, Institute for Color Science and Technology

² Department of Surface Coatings and Corrosion;Center of Excellence for Color Science and Technology, Institute for Color Science and Technology

³ Department of Polymer Engineering and Color Technoloty, Amirkabir University of Technology

Abstract

In this study, an accelerated electrochemical test was introduced as modified AC/DC/AC test. This test consists of D.C. polarization, soaking and dry cycles. The evaluated coating was cathodic electrocoating that electrodeposited on phosphated mild steel substrate with an average thickness of 20 microns and cured in three different conditions. In this research, the protective behavior of cathodic electrocoatings was investigated using the modified AC/DC/AC test, EIS and salt spray tests. Results showed that cathodic electrocoatings with low crosslinking density have better resistance against mechanical stresses during the modified AC/DC/AC test because of their more flexibility. On the other hand, due to the poor resistance against electrochemical stresses, final loss of protective properties of low-crosslinked electrocoatings are notable. The study manifests good correlation between the results of carried tests which the acceleration of coating degradation under the modified AC/DC/AC test conditions is the most.

Keywords