Facile fabrication of superhydrophobic surfaces with low roughness on Ti–6Al–4V substrates via anodization

•A facile and efficient method for fabricating low-roughness superhydrophobic titanium alloy surfaces is successfully developed.•Formation mechanism of micro-scale pore structures built by a novel anodic oxidation is carefully analyzed.•The prepared superhydrophobic surface possesses good durability and abrasion resistance. The combination of suitable micro-scale structures and low surface energy modification plays a vital role in fabricating superhydrophobic surfaces on hydrophilic metal substrates. This work proposes a simple, facile and efficient method of fabricating superhydrophobic titanium alloy surfaces with low surface roughness. Complex micro-pore structures are generated on titanium alloy surfaces by anodic oxidation in the NaOH and H2O2 mixed solution. Fluoroalkylsilane (FAS) is used to reduce the surface energy of the electrochemically oxidized surface. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Zygogpi-xp6 (ZYGO) and contact angle measurements are performed to determine the morphological features, chemical composition, surface roughness and wettability. The formation mechanism of micro-scale rough structures, wettability of the superhydrophobic surfaces and the relationship between reaction time with wettability and roughness of the superhydrophobic surfaces are also analyzed in detail. The as-prepared titanium alloy surfaces not only show low roughness Ra=0.669μm and good superhydrophobicity with a water contact angle of 158.5°±1.9° as well as a water tilting angle of 5.3°±1.1°, but also possess good long-term stability and abrasion resistance.