Friction and Wear of MoS₂ Films on Etched Steel Surfaces

Surface texturing is one of modern technologies using for improvement friction and wear properties of rubbed surfaces. The simple and effective methods of surface texturing are mechanical or chemical treatments of friction surfaces. In this work we deal with chemical treatment of steel surfaces with following filling the profile by solid lubricant particles as MoS₂. The steel surfaces were etched with phosphoric acid. The effect of time and temperature of etching on the surface roughness parameters was studied. Some standard roughness parameters of etched surface were measured. It was found that the parameters of roughness as Rz and Sm characterizing the depth of valleys and their size can be used for description of etched surfaces. Optimal parameters, Rz and Sm, providing the best tribological properties were determined: Rz = 5 ∼ 7 m and Sm = 50–70 m. The thickness of solid lubricant film was about 1 m. Finally, the tribological properties of MoS₂ films on the steel surfaces textured by chemical treatment were performed. The friction coefficient and wear life of solid lubricant films was assessed. Friction and wear properties of MoS₂ films on etched surfaces were compared with similar films on virgin steel surface. The wear life of MoS₂ films on etched surfaces was 5–7 times larger than for solid lubricant film on mechanically treated steel surface.