Effect of AC interference on failure mechanism of zinc-rich epoxy coatings in alkaline environment

Abstract In this paper, the failure mechanism of Zn-rich epoxy coating under AC interference in alkaline environment was revealed based on EIS tests. Using X80 steel as matrix, coated sample formed by hand-brushing with thickness 25 ± 5 μ m determined five-point test. The curves 3 wt% NaOH solution immersion time studied (no) interference, and evolution established through fitting parameters. results showed that during curing process coating, Zn reacted O 2 air to generate ZnO, which surface particle form ZnO-Zn structure. environment, ZnO dissolved Zn(OH) , namely activation particles, inhibited interference. Furthermore, activated particles is, electrochemical reaction significantly promoted conclusion, non-conductive generated together un-activated can not only isolate electrical connection between but also cut off cathodic protection Fe. Meanwhile, matrix Fe passivated weakened wet binding force resulting stripping.