Quality Control Metrics to Assess MoS2 Sputtered Films for Tribological Applications

Pure molybdenum disulfide (MoS2) solid lubricant coatings could attain densities comparable to doped films (and the associated benefits to wear rate and environmental stability) through manipulation of the microstructure via deposition parameters. Unfortunately, pure films can exhibit highly variable microstructures and mechanical properties due to processes that are not controlled during deposition (i.e., batch-to-batch variation). This work focuses on developing a relationship between density, hardness, friction, and wear for pure sputtered MoS2 coatings. Results show that dense films (ρ = 4.5 g/cm3) exhibit a 100 × lower wear rate compared to porous coatings (ρ = 3.04–3.55 g/cm3). The tribological performance of high density pure MoS2 coatings is shown to surpass that of established composite coatings, achieving a wear rate 2 × (k = 5.74 × 10–8 mm3/Nm) lower than composite MoS2/Sb2O3/Au in inert environments.