Facile Preparation of Hierarchical Micro‐/Nanostructure Superhydrophobic Surface with Excellent Corrosion Resistance on Ti6Al4V‐Based Composite for Nuclear Fuel Reprocessing

Abstract

To address the poor corrosion resistance of titanium matrix composites treatment vessels for nuclear fuel reprocessing in HF solution at room temperature and high concentration of HCl/HNO3 solutions at high temperature, hierarchical micro‐/nanostructure surfaces with adjustable superhydrophobicity are prepared on Ti6Al4V‐based composites by laser microengraving followed by fluorosilane modification. The effect of topography and composition of the surface on wettability is investigated. More importantly, the anticorrosion mechanism of the as‐prepared surface in the earlier corrosive solutions that can destroy the anticorrosion inert oxide film of the composite easily is investigated and elucidated for the first time. The results indicate that the surface is composed of regular parallel linear peak‐like microscale structures and radiating flocculent nanostructures. It shows excellent and stable superhydrophobicity (contact angle of 158.4°, sliding angle of 4.7°). Due to the unique solid–air–liquid interface induced by the micro‐/nanostructures and high charge transfer resistance induced by the fluorosilane film, the impedance modulus of the superhydrophobic surface can be one order of magnitude higher than that of the bare surface. The composite can be corroded hardly when immersed in 5% HCl/HNO3 solutions at 80 °C for more than 10 days and 4% HF solution at room temperature for 3 days.