Wettability of hydraulically profiled low-carbon steel substrates

Surfaces obtained after water jet treatment were evaluated in terms of roughness and static equilibrium contact angles. Relationships between standard roughness parameters and measured contact angles could not be established. A model introduced by Kubiak et al. [Wear 271 (2011) 523–528] was utilised, which provided qualitatively correct trends. Exceptions were situations with very short exposure times. In terms of quantitative evaluation, the model generally overestimated the measured contact angles on isotropic surfaces. It is suggested that the formation of very narrow cracks in the surface can obliterate geometric profile effects and deteriorate wettability.

► No general relationship between roughness parameters and contact angle was found.
► An empirical model could qualitatively be related to contact angles.
► In terms of quantity, calculated contact angles were too high.
► Very narrow cracks might obliterate profile effects and deteriorate wettability.