An investigation of the wettability and chemical stability of superhydrophobic coatings on titanium

Abstract

This study employs a two-step process to fabricate a superhydrophobic surface on the titanium substrate with outstanding corrosion resistance and chemical stability. Initially, a shot-peening treatment was carried out on the titanium surface, followed by chemical etching. Once the etching process was complete, the surface was modified with Methyltrichlorosilane (MTCS) to lower its surface energy. The impact of shot peening on wettability, corrosion resistance, and long-term chemical stability of the produced superhydrophobic surfaces was then investigated. Scanning electron microscopy images demonstrated the formation of fibrous network structure in the nanoscale, and Fourier transform infrared spectroscopy analysis confirmed the existence of chemical bonds between the functional groups of MTCS and the titanium surface. Furthermore, the corrosion resistance of the superhydrophobic surface was evaluated using immersion, potentiodynamic polarization, and an electrochemical impedance spectroscopy test in a 3.5 wt% NaCl solution. The long-term stability of the fabricated coating was tested by immersing samples in a 3.5 wt% NaCl solution for various immersion times. Based on the obtained results, the pre-shot peened samples exhibited a maximum water contact angle of 159° after MTCS modification. Furthermore, they also demonstrated excellent corrosion resistance and stability.