Superhydrophobic coating on modified 9Cr – 1Mo ferritic steel using perfluoro octyl triethoxy silane

Abstract

Lotus leaves are a typical example of superhydrophobic surface. Numerous studies have confirmed that surface morphology possessing micro- and nanoscale roughness along with a low surface energy material coating leads to apparent water contact angle (WCA) ⩾150°. In nuclear power plants, modified 9Cr–1Mo ferritic steel is the favoured steam generator tubing material. During transit, storage and installation, SHP surface on modified 9Cr–1Mo ferritic steel can impart good corrosion resistance to retain the integrity of the specimen during operation. In this study, SHP surface of modified 9Cr–1Mo ferritic steel with a WCA of 150±1° was successfully achieved by polishing, etching, perfluoro octyl triethoxy silane coating and baking. The WCA and contact angle hysteresis were measured. The surface morphology and the composition were characterised by atomic force microscopy and attenuated total reflection–infrared spectroscopy respectively. Superhydrophobicity and its related theories are also discussed in this paper.

Keywords:

• Modified 9Cr – 1Mo ferritic steel
• Silane coating
• Water contact angle
• Superhydrophobicity

Acknowledgement

M. Ezhil Vizhi acknowledges the University Grants Commission-Department of Atomic Energy (UGC-DAE) Consortium for Scientific Research for the financial assistance through Junior Research Fellowship.