Quality Control Metrics to Assess MoS2 Sputtered Films for Tribological Applications
Tomas F. Babuska, John F. Curry, Michael T. Dugger, Morgan R. Jones, Frank W. DelRio, Ping Lu, Yan Xin, Tomas Grejtak, Robert Chrostowski, Filippo Mangolini, Nicholas C. Strandwitz, Md Istiaque Chowdhury, Gary L. Doll, Brandon A. Krick
Abstract
Abstract Pure molybdenum disulfide (MoS 2 ) 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 MoS 2 coatings. Results show that dense films ( ρ = 4.5 g/cm 3 ) exhibit a 100 × lower wear rate compared to porous coatings ( ρ = 3.04–3.55 g/cm 3 ). The tribological performance of high density pure MoS 2 coatings is shown to surpass that of established composite coatings, achieving a wear rate 2 × ( k = 5.74 × 10 –8 mm 3 /Nm) lower than composite MoS 2 /Sb 2 O 3 /Au in inert environments.