Effects of Microstructure and Adhesion on Performance of Sputter-Deposited MoS2 Solid Lubricant Coatings

Selection of a lubricant for a given application (use) is determined by a number of factors. Analogous to fluid lubricants, where proper base stock, additive package, and formulation are selected for the application, choice of dry lubricants requires consideration of the appropriate deposition procedure, film composition, film structure, and substrate surface preparation procedure. The relationship between film physical and mechanical properties of MoS 2 produced by rf, de, and rf magnetron sputtering is reviewed. We propose that when the requirements of contact geometry, pressures (stresses), and operating life are considered, optimization of three essential properties of the coatings will provide the ultimate in performance: 1) good coating-substrate adhesion, 2) dense, small grain size (low porosity), and 3) high chemical (phase) purity.