Effect of the specific surface topography on surface wettability of chromium-based coatings

Surfaces featuring hydrophobic behaviour are generally prepared by a wide spectrum of technologies featuring different process complexity (anodic oxidation, lithography, electrodepositing, etc.). The aim of the work was to use a relatively simple method of magnetron sputtering to prepare metallic hydrophobic surface. Chromium coatings were selected due to their high adhesion to steel and corrosion resistance while conserving certain level of hardness and ductility. The tested coatings included pure Cr and pure Cr with CrN interlayer. The resulting contact angle value of up to 111 degrees has confirmed hydrophobic behaviour. The resulting surface morphology is formed by almost perfectly developed crystals in the shape of hexagonal pyramids providing a suitable surface roughness conditions for hydrophobicity.