Abstract
This paper presents key findings from an ongoing study on the marine corrosion behavior of thermally sprayed zinc and aluminum coatings. Zn, Al, and Zn-Al layers of varied thickness were applied to twelve steel pipes by arc and flame spraying and subjected to different post-spray treatments such as sealing and painting. The pipes are mounted vertically on a test rig in the Pacific Ocean and have been inspected annually to record the appearance and thickness of the coatings. After 7 years, the Zn coatings began to show signs of degradation in the immersed portion of the pipe, although no such changes occurred with Al and Zn-Al coatings. After 18 years, heavily damaged sections of three pipes were removed and new pipe was welded in place. The repaired regions were coated with Al-5%Mg, which has performed well so far.
