Organosilane-functionalized hydrothermal-derived coatings on titanium alloys for hydrophobization and corrosion protection

• Published in: Progress in organic coatings Vol. 142; p. 105594
• Main Authors: Rahimipour, S., Rafiei, B., Salahinejad, E.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.05.2020; Elsevier BV
• Subjects: Aqueous solutions; Contact angle; Corrosion; Corrosion prevention; Corrosion resistance; Corrosion resistant alloys; Electrochemical impedance spectroscopy; Hydrophobicity; Organosilanes; Potentiodynamic polarization; Roughening; Surface energy; Surface free energy; Titanium alloys; Titanium base alloys; Titanium-based alloys; Wettability; Potentiodynamic polarization; Surface free energy; Organosilanes; Titanium-based alloys; Electrochemical impedance spectroscopy
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2020.105594

•The size of alkaline processing cavities increases with the NaOH concentration.•Alkaline processing and HDTMS coating induces hydrophilicity and hydrophobicity, respectively.•Alkaline processing reduces, but the HDTMS processing improves the corrosion resistance. This work focuses on the structure, wettability and corrosion behaviors of Ti-6Al-4 V alloy after roughening treatments in different concentrations of NaOH aqueous solutions followed by low surface energy hexadecyltrimethoxysilane (HDTMS) coating. In this regard, scanning electron microscopy, contact angle measurements, potentiodynamic polarization and electrochemical impedance spectroscopy were used to characterize the samples. In contrast to hydrophilicity caused by the hydrothermal alkaline treatments, the subsequent HDTMS coating donated considerable hydrophobicity. Typically, the highest sessile water contact angle (about 147°) was obtained for the sample treated in 3 M NaOH solution followed by the HDTMS coating. In addition, the alkaline treatment reduced the corrosion resistance of the surface in a NaCl aqueous solution; however, the HDTMS hydrophobization process improved it significantly. It is eventually concluded that the coupled use of alkaline treatment and HDTMS functionalization can be further considered for moisture-exposed applications of Ti-based alloys.