Abstract
Thermally sprayed aluminum (TSA) has been used in offshore applications for decades, protecting steel structures from seawater corrosion. However, very little work is reported on the performance of TSA when damaged, particularly in deep sea applications. This paper presents the results of a study in which an arc-sprayed aluminum-coated steel sample was subjected to synthetic seawater at 5 °C for 30 days in an autoclave at 50 MPa to simulate 5000 m of water pressure. Discontinuities or “holidays” amounting to 3% of the sample area were drilled into the coatings, exposing the underlying steel to direct attack by the synthetic seawater. After testing, SEM and EDX analysis revealed the formation of a protective Mg-based layer on the exposed steel with negligeable calcium content and no visible corrosion products. The results indicate that TSA coatings can protect steel in deep sea environments even when damaged.
