ION-BOMBARDMENT OF SOLID LUBRICATING NANOPARTICLE COATINGS

Transition-metal dichalcogenides MeX2, where Me is Mo or W and X = S, are used as solid lubricants. Sputtered coatings rarely exceed the com position MeX1.7. Stoichiometric coatings, however, perform optimally, and the present paper will report on a novel stoichiometric coating pr ocedure with ion bombardment as a post-coating process. Stoichiometric -powder granulates of MeX2 were dispersed in isopropanol and ball-mill ed to obtain a nanoplatelet suspension. The coating was deposited by e lectrospraying from a modified hypodermic needle at a high voltage pot ential of 20 kV. Electrospraying of MoS2, WS2, and NbS2 will be discus sed. Tribological testing of as-deposited and ion-bombarded samples wi ll be reported, and due to the prospective applications of WS, as a ca ndidate for high-temperature, solid lubrication, this paper will empha size this material.