Wettability enhancement of Inconel 625 alloy by fabricating ordered micro-textures through micro-milling

Abstract

Surface texturing with micro- and nano-scale features has emerged as an innovative and robust approach to addressing functional challenges like surface wettability and tribological performance. Among the various techniques, mechanical micro-fabrication stands out for its ability to create highly precise micro-textures in a single step, making it scalable and cost-effective. This study presents a straightforward, one-step mechanical micro-fabrication method such as micro ball-end milling, micro flat-end milling, and micro-drilling for producing micro-dimple patterns on Inconel 625 (IN625) to modify surface topography and enhance wettability. Key parameters, such as texture shape, size, and pitch, were systematically analyzed to evaluate their impact on surface topography. Preliminary findings revealed that the introduction of ordered dimples through micro-milling significantly altered the surface characteristics when compared to untextured surfaces. While the untreated IN625 surface exhibited hydrophobic behavior, micro-texturing transformed it into a hydrophilic surface. The enhancement in wettability was attributed to a combination of factors, including increased surface roughness, texture geometry, and the initial surface condition. Among the different configurations, the untextured surface exhibited the highest contact angle of 101°, whereas the ball-end mill micro-textured surface with the smallest pitch produced the lowest contact angle of 47°.