Tribology Letters

, Volume 53, Issue 1, pp 329–336 | Cite as

Surface and Subsurface Contributions of Oxidation and Moisture to Room Temperature Friction of Molybdenum Disulfide

  • H. S. Khare
  • D. L. Burris
Original Paper


Molybdenum disulfide (MoS2), a lamellar solid lubricant, is used extensively in space applications due to its exceptional performance in vacuum and inert environments. The friction and wear of MoS2, however, increase in the presence of atmospheric contaminants, such as water. Despite numerous studies of the moisture-sensitive friction response of MoS2 over the decades, important fundamental questions remain unanswered. Two leading hypotheses suggest that water affects friction by causing the MoS2 to oxidize or by physically bonding to edge sites, and thereby disrupting easy lamellar shear. This paper presents a parametric study to (1) isolate the effects of water and oxygen on ambient MoS2 friction, (2) identify the effect of water and oxygen on MoS2 oxidation, and (3) distinguish between the effects of water diffusion and surface oxidation on the frictional response of MoS2 coatings. The experimental findings were used to develop a qualitative model for the effects of environment on MoS2 friction; the model is used to explain transients, hysteretic effects, oxidation effects, and effects of physically bound water.


MoS2 Friction Water Solid lubrication 



The authors gratefully acknowledge the Air Force Office of Scientific Research (AFOSR YIP FA9550-10-1–0295) and the University of Delaware Graduate Fellowship for financial support of this work.


  1. 1.
    Ross, S., Sussman, A.: Surface oxidation of molybdenum disulfide. J. Phys. Chem. 59(9), 889–892 (1955)CrossRefGoogle Scholar
  2. 2.
    Haltner, A.J., Oliver, C.S.: Effect of water vapor on friction of molybdenum disulfide. Ind. Eng. Chem. Fundam. 5(3), 348–355 (1966)CrossRefGoogle Scholar
  3. 3.
    Pardee, R.P.: Effect of humidity on low-load frictional properties of a bonded solid film lubricant. ASLE Trans. 15(2), 130–142 (1972)CrossRefGoogle Scholar
  4. 4.
    Panitz, J.K.G., Pope, L.E., Lyons, J.E., Staley, D.J.: The tribological properties of Mos2 coatings in vacuum, low relative-humidity, and high relative-humidity environments. J. Vac. Sci. Technol. A-Vac. Surf. Films 6(3), 1166–1170 (1988)CrossRefGoogle Scholar
  5. 5.
    Stewart, T.B., Fleischauer, P.D.: Chemistry of sputtered molybdenum-disulfide films. Inorg. Chem. 21(6), 2426–2431 (1982)CrossRefGoogle Scholar
  6. 6.
    Fleischauer, P.D.: Effects of crystallite orientation on environmental stability and lubrication properties of sputtered Mos2 thin-films. ASLE Trans. 27(1), 82–88 (1984)CrossRefGoogle Scholar
  7. 7.
    Dudder, G., Zhao, X., Krick, B., Sawyer, W.G., Perry, S.: Environmental effects on the tribology and microstructure of MoS2-Sb2O3-C films. Tribol. Lett. 42(2), 203–213 (2011)CrossRefGoogle Scholar
  8. 8.
    Midgley, J.W.: The frictional properties of molybdenum disulfide. J. Inst. Petrol. 42, 312–315 (1956)Google Scholar
  9. 9.
    Johnston, R.R., Moore, A.J.W.: Water adsorption on molybdenum disulfide containing surface contaminants. J. Phys. Chem. 68(11), 3399–3406 (1964)CrossRefGoogle Scholar
  10. 10.
    Roberts, E.W.: Towards an optimised sputtered MoS2 lubricant film. 20th AMS NASA Conference, 103–119 (1986)Google Scholar
  11. 11.
    Colbert, R.S.: The Role of Water on the Tribological Properties of Molybdenum Disulphide Films. Doctoral Dissertation, University of Florida, Gainesville (2012)Google Scholar
  12. 12.
    Holinski, R., Gänsheimer, J.: A study of the lubricating mechanism of molybdenum disulfide. Wear 19(3), 329–342 (1972)CrossRefGoogle Scholar
  13. 13.
    Windom, B.C., Sawyer, W.G., Hahn, D.W.: A Raman spectroscopic study of MoS(2) and MoO(3): applications to tribological systems. Tribol. Lett. 42(3), 301–310 (2011)CrossRefGoogle Scholar
  14. 14.
    Kubart, T., Polcar, T., Kopecky, L., Novak, R., Novakova, D.: Temperature dependence of tribological properties of MoS(2) and MoSe(2) coatings. Surf. Coat. Technol. 193(1–3), 230–233 (2005)CrossRefGoogle Scholar
  15. 15.
    Godfrey, N., Nelson, E.C.: Oxidation characteristics of molybdenum disulfide and effect of such oxidation on its role as a solid film lubricant. NACA TN No. 1882 (1949)Google Scholar
  16. 16.
    Khare, H.S., Burris, D.L.: The effects of environmental water and oxygen on the temperature-dependent friction of sputtered molybdenum disulfide. Tribol. Lett. 52(3), 485–493 (2013). doi: 10.1007/s11249-013-0233-8 CrossRefGoogle Scholar
  17. 17.
    Hamilton, M.A., Alvarez, L.A., Mauntler, N.A., Argibay, N., Colbert, R., Burris, D.L., Muratore, C., Voevodin, A.A., Perry, S.S., Sawyer, W.G.: A possible link between macroscopic wear and temperature dependent friction behaviors of MoS(2) coatings. Tribol. Lett. 32(2), 91–98 (2008)CrossRefGoogle Scholar
  18. 18.
    Burris, D.L., Perry, S.S., Sawyer, W.G.: Macroscopic evidence of thermally activated friction with polytetrafluoroethylene. Tribol. Lett. 27(3), 323–328 (2007)CrossRefGoogle Scholar
  19. 19.
    Burris, D.L., Sawyer, W.G.: Addressing practical challenges of low friction coefficient measurements. Tribol. Lett. 35(1), 17–23 (2009)CrossRefGoogle Scholar
  20. 20.
    Chromik, R.R., Baker, C.C., Voevodin, A.A., Wahl, K.J.: In situ tribometry of solid lubricant nanocomposite coatings. Wear 262(9–10), 1239–1252 (2007)CrossRefGoogle Scholar
  21. 21.
    Kanaya, K., Okayama, S.: Penetration and energy-loss theory of electrons in solid targets. J. Phys. D Appl. Phys. 5(1), 43 (1972)CrossRefGoogle Scholar
  22. 22.
    Lansdown, A.R.: Molybdenum Disulphide Lubrication, 1st ed. Tribology Series, 35. Elsevier, Amsterdam (1999)Google Scholar
  23. 23.
    Scharf, T.W., Prasad, S.V.: Solid lubricants: a review. J. Mate. Sci. 48(2), 511–531 (2013). doi: 10.1007/s10853-012-7038-2 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringUniversity of DelawareNewarkUSA

Personalised recommendations