Wettability modification of the AISI 304 and 316 stainless steel and glass surfaces by titanium oxide and titanium nitride coating

The improvement of the conductive and inhibitory properties of the stainless-steel electrodes used in an electrochemical environment by the application of coatings is of great interest in the field of, for example, heavy crudes, among others. And titanium-based materials, such as titanium dioxide (TiO₂), titanium oxide (TiO_x) and titanium nitride (TiN), are good candidates as coatings because of their anti-corrosive properties. This work reports the contact angle variation of a water drop measured on the surfaces of samples of AISI 304 and 316 stainless steel and of glass when coated with TiO₂, TiO_x and TiN films of approximately 600 nm thick. The films were produced by sputtering by varying the power and the gas flow parameters. Chemical and structural analysis by X-ray diffraction (XRD), energy division of the characteristic x-ray spectroscopy (EDS) and selected area electron diffraction (SAED) patterns in the transmission electron microscope (TEM) confirm the presence of the TiO₂, TiO_x and TiN phases in the films produced. On the glass surface, the contact angle ranged from 10° (hydrophilic behavior) on uncoated glass to 92° (hydrophobic behavior) on coated glass. Coating the surface of the AISI 316 and 304 stainless steel with these films also increased the contact angle up to 90°. The TiN films roughness, measured by atomic force microscopy (AFM), and average particle size, measured by scanning electron microscopy (SEM) and TEM, favored the increment of the contact angle.