Friction and Lifetime of Laser Surface-Textured and MoS_2-Coated Ti6Al4V Under Dry Reciprocating Sliding

摘要

The use of lasers for creating defined textured patterns on surfaces has steadily gained attention during the past decade. These textures can contribute to friction reduction by acting as a reservoir for lubricant, hydrodynamic bearing and trap for wear debris. In the present work, titanium alloy surfaces were textured using a nanosecond pulsed laser and subsequently coated with MoS_2. The samples were tested under dry reciprocating sliding conditions using two different oscillation amplitudes. During the test, the evolution of the coefficient of friction as a function of the number of cycles was measured until coating failure. The influence of the dimple distance on friction and lifetime was evaluated and verified by post-mortem analyses of the samples using optical, confocal and SEM microscopy as well as EDS and XPS analyses. The results show that under certain conditions, surface texturing can reduce friction, extend the lifetime of the coating and provide a progressive coating degradation until failure.