Surface roughness assessment of zinc oxide nanostructures formed on biomedical steel

This investigation explores the effect of hydrothermal time on the topographical characteristics of zinc oxide nanostructures-based coating formed on AISI 316L steel. First, a Zn adhesion layer was deposited and later a ZnO film. Next, the ZnO nanostructures were grown by the hydrothermal method at a temperature of 90 °C for 60 and 120 minutes. Elemental analysis was conducted at the surface and its topographic characteristics were assessed by atomic force microscopy. After images acquisition of the surface of the samples, arithmetic roughness (Ra), root mean square roughness (Rq), kurtosis (Rk) and skewness (Rsk) were determined. The arithmetic roughness Ra varied from ~26 nm to ~41 nm when hydrothermal time increased from 60 to 120 min, whereas Rq increased from ~35 nm to ~53 nm. Regarding the kurtosis and skewness parameters, when varying the hydrothermal time, a decrease in their values was found.