Zinc-rich primers-Test performance and electrochemical properties

The performance of coating systems with different types of zinc-rich primers has been tested in a 5 years offshore field test. All the coating systems with zinc silicate primers performed well in the test. The performance of the coating systems with zinc epoxy primers varied. Two of them suffered from large local scribe creep attacks, while the third performed well. Zinc silicate shop primer systems performed surprisingly well, considering the low zinc loading. Coating systems without any zinc-rich primer, where epoxymastic were applied directly on blast cleaned steel, performed reasonably well. There was a certain correlation between electrochemical properties of the primers and performance in the field test. Film thickness of the zinc-rich primers probably affected the electrochemical properties and the field test performance.