Enhancing the hydrophobicity of Ti–6Al–4V through multi-level electrical discharge texturing

In the current work, single and multi-level micro-texturing on Ti–6Al–4V surfaces was performed through electrical discharge micromachining. The wetting properties of the single-level features obtained through EDMM have been studied, which revealed a higher water contact angle (CA) of ∼110° with respect to an untextured surface (water CA ∼38°). The concept of dimples overlapping (% of overlap between adjacent dimples) has been adopted to propose a novel technique for the simultaneous machining of multiple micro-features through a simpler cylindrical tool electrode, which otherwise necessitates multi-step fabrication or preformed tools. Adopting the proposed concept, multi-level textures consisting of micro-dimples surrounded by micro-pillars were machined on the Ti–6Al–4V surface. With multi-level textures, the water CA increases significantly compared to the untextured surfaces. The maximum water CA ∼ 104.2° was obtained with a 300 µm diameter tool and 25% dimple overlap, thereby rendering the surface hydrophobic.