Influence of roughness on polar and dispersed components of surface free energy and wettability properties of copper and steel surfaces

The most urgent problems in meso-, micro- and nano-technological productions are controlling wetting of metals and alloys and liquid spreading over engineering surfaces after their hardware abrasive processing. Nowadays, there is a lack in theoretical basis and comprehensive experimental studies to predict the texture formation and change of the functional surface properties (including wetting) of metals and alloys after abrasive processing. In this study, based on the analysis of the three dimensional roughness parameters (amplitude, hybrid and feature) and elemental composition of the near-surface layer, the features of texture formation, changes in the surface free energy and wettability of copper and steel surfaces that are widely used in industry were established after their hardware abrasive processing. The use of abrasive material with an average grit size of up to 100 mu m was found to significantly change the surface roughness. The abrasive processing significantly modifies the polar component in the surface free energy, while not influencing its dispersed component. The texture parameters allowing one to control both the growth and decrease of the polar component in the surface free energy were determined. It is shown that the abrasive processing directly influences the wettability properties and allows varying the contact angles in a sufficiently wide range of from 54.0 degrees to 108.2 degrees (for copper surfaces) and from 71.6 degrees to 89.5 degrees (for steel surfaces).