Surface texturing is a process of fabricating specific patterns on a surface to enhance surface properties such as friction, contact area, air aspiration, wear, hydrophobicity, etc. Fabricating surfaces with planned micro features is an effective method to improve tribological performance of the interacting surfaces. Laser surface texturing process is one of the best suitable processes for producing micro-patterns. Micro textures are imparted on HSS discs using CO2 laser, varying the shape and dimensions of the resulting dimples affecting the frictional coefficient and wear. Experiments have been accomplished to determine effects of textural variations such as areal density of dimples, dimple shape, area of dimples and depth of dimples on the Coefficient of Friction (COF) and Wear. Effects of lubrication conditions (Dry and Wet), pin material (MS, SS, EN31), applied load (25N, 50N, 75N) and Sliding velocity (400 rpm, 800 rpm and 1200 rpm) are evaluated on COF and Wear. Tests have been performed on pin-on-disk apparatus along guidelines of Taguchi L18 Orthogonal Array, keeping constant sliding distance of 940 m (about 10,000 cycles). Experimentally, it is found that wet lubricated, circular shaped dimples, with areal density 7.5%, dimple area 0.09 mm2 with MS material pin provides best results. This experimental analysis has been performed to test the applicability, efficiency and reliability of the textured surfaces.

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Hydrophobicity is a prominent characteristic of a surface that governs its applications in domains such as wear reduction by lubrication retention, self-cleaning surfaces, fluid drag reduction, viscosity testing, development of oleophobic coatings, etc. A superhydrophobic surface exhibits a water contact angle (CA) of 150∘ or larger. High surface energy of nontextured surface limits its wettability. Texturing of a surface imparts low surface energy which proves to be favorable for enhancing the overall surface hydrophobicity. Research and analysis done to fathom an optimum method by which surfaces accomplish superhydrophobicity is still miniscule. It is challenging to fabricate superhydrophobic surfaces by micro-machining due to the expansive range of the features involved. To minimize the exorbitant costs incurred due to trial-and-error-based experimentation, a mathematical model with [Formula: see text]90% accuracy has been developed in this study, which would help determine the closest ranges of values of parameters like micro-dimple diameter and areal density responsible for inducing superhydrophobic properties on a micro-dimpled specimen. The exceptionality of this study lies in the fact that though mathematical models are available for textures like micro-grooves and micro-pillars, but miniscule research is available for micro-dimpled surfaces with hardness greater than 55 HRC.

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