High Performance Arc Sprayed Coatings for Active Corrosion Protection in Offshore Applications

This work assesses various ways of improving the corrosion protection and service life of thermally sprayed coatings used in offshore structures. Test results show that improvement is possible even in the case of Zn-Al15 spray coatings and, that in some cases, coating thickness can be reduced without loss of corrosion protection. Test samples were prepared by arc and cold-gas spraying and some of the coatings were sealed. The protective characteristics of the various coating systems were evaluated in a 25-week cyclic aging test as defined in ISO 20340. The results are compared based on the degree of blistering, rusting, and corrosion penetration at the scratch as well as adhesion to the substrate.