Optimised Bonded Solid Lubricant Technology

Optimized bonded solid lubricant technology depends on lubricant formulation and application. Using a ring/block test rig bonded solid lubricants were investigated containing molybdenum disulfide, graphite and antimony-thioantimonate. For evaluating the tribological properties wear life depending on speed and load as well as wear rate resulting in wear coefficients were measured. In addition the friction behaviour was determined. Optimum solid lubricant concentrations of two component lubricants containing MoS2/graphite or MoS2/Sb(SbS4) resulted in remarkable improved tribological properties compared with single component formulations. Antimony-thioantimonate possessing no usable tribological properties at all can improve these properties of other solid lubricants. Therefore a new three component lubricant containing optimum concentrations of MoS2, graphite and Sb(SbS4) was developed exhibiting much better lubricating properties than single and two component formulations as well as commercially available bonded solid lubricants. Regarding application technology the influence of running-in was investigated because certain bonded solid lubricant films need such a process in order to obtain maximum wear life curves. For these investigations that time was defined as completion of the running-in process after which no further change of the coefficient of friction occurs for the given speed and load conditions. It was found that this running-in process was completed after different time periods for different lubricants. Obviously the influence of the running-in process on wear life is the result of the smoothing and compressing of the lubricant film depending on its film formation properties.