Thermally sprayed aluminium (TSA) has been used in offshore applications for decades. Their effectiveness in mitigating corrosion of steel structures in presence of seawater has been proven over the years. However, very little work is reported on the performance of TSA when damaged. Furthermore, data on the performance of damaged TSA in deep sea is virtually non-existent. The paper addresses this knowledge gap and reports the corrosion performance of damaged TSA in a simulated deep sea environment. Holiday amounting to ～3% of the sample area was drilled to expose the underlying carbon steel and the sample was exposed to synthetic seawater at 5℃ for 30 days in an autoclave at 50MPa to simulate 5000m of water pressure. After testing, examination of the sample revealed the formation of calcareous deposit on the exposed steel surface with no visible steel corrosion product. Detailed microstructural characterisation of the calcareous deposit confirmed the formation of protective Mg-based layer with negligeable Ca-based material. Thus, one can conclude that TSA can protect carbon steel in deep sea environment even when damaged.
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