Topology‐Enhanced Lubricant‐Limited Domains Laser Direct‐Written Micropit Structures on Stainless Steel Surfaces to Counteract Thermocapillary Migration Effects

Aiming at the problem of localized oil depletion due to thermocapillary migration of lubricating oil on a stainless steel surface under a temperature gradient, this study proposes a domain‐limited regulation strategy of micropit arrays based on laser direct writing technology. The micropit arrays with recast layer thickness are prepared on the surface of 304 stainless steel by the negative ionization laser ablation process, and the regulation mechanism of PAO4 oil droplet thermal migration behavior by different pit intervals and diameters is systematically investigated. The experimental results show that the micropits significantly inhibit the oil droplet migration through the structural pinning effect, and changing the diameter of the micropits significantly affects the density of pinned lines, which in turn affects the steady‐state migration distance. Based on lubrication theory and the modified Navier–Stokes equations, a kinetic model of lubricant thermal migration on micropit structured surfaces is established, which provides a reference for the exploration of the multifield coupling mechanism of surface tension gradient driving, viscous dissipation, and pinning resistance. This study provides new design and processing ideas for woven‐structured lubricated surfaces.