Hydrophobicity and high-temperature corrosion resistance nano-modified organic silicone coatings in alternating environments

• Hydrophobic silicone coating used in cyclically alternate corrosion environment. • Failure mechanism of organic silicone coating in cyclically alternate corrosion process. • Hydrophobic coating protective mechanism in cyclically alternate corrosion process. Three organic silicone coatings containing different contents of nano-sized Ti and Al powders were prepared on 304SS substrates. Their resistance against cyclic corrosion tests was carried out. Each cycle of the corrosion tests includes 22 h of salt spraying test at 35°C and consecutive 2 h of oxidation test at 400°C. The results revealed that the coating with 10 wt.% Ti powders exhibited self-healing performance, the highest corrosion resistance, and the best hydrophobicity. Though addition of nano-Al into the coatings is beneficial to enhancing the hydrophobicity, but results in spallation during corrosion tests. This study demonstrates the correlation between hydrophobicity of nano-modified organic silicone coatings and resistance against corrosion in alternating environments.