Synthesis, structural and tribological properties of tailored MoSex / WSx based coatings for multi-environment industrial applications

Transition metal dichalcogenide (TMD) coatings have been employed as industrial low friction solid lubricants for machine components operating in vacuum and dry environments. However, their properties degrade in ambient air due to low moisture resistance. Moreover, the pure TMD coatings possess high porosity, low oxidation resistance, and poor adhesion to substrates, leading to easy mechanical exfoliation. In this study, a novel approach of multilayered architecture of coatings deposited from MoSe 2 and WS 2 targets, with varying period thickness had been introduced as potential solution for components operating in multi-environments. A series of monolayer and multilayered coatings were deposited using DC (direct current) magnetron sputtering technique, to study the influence of coating architecture on the composition, morphology, structure, mechanical and sliding response. The sliding tests were conducted under various conditions, including normal air, dry nitrogen, and multiple temperatures (25 °C, 100 °C, and 200 °C). From 25 °C to 100 °C, temperature increase removed moisture, generally reducing friction, except for the MoSe x coating, which performed better at room temperature. At 200 ºC, wear and friction increased significantly due to enhanced tribo-oxidation. The wear performance in dry nitrogen follows the same trend observed in normal air, but with reduced values. The coatings depicted promising sliding properties in diverse environments with temperature applicability limited to 100 ºC. The coating with the lowest period demonstrated the best overall mechanical and tribological performance under the tested conditions selected for this work. The friction was mainly influenced by the atmosphere, while temperature significantly affected both friction and wear performance.