Atomic oxygen-MoS/sub 2/ chemical interactions
The present study shows that, at 1.5 eV O-atom translation energy, SO/sub 2/ is generated and outgases from an anhydrous MoS/sub 2/surface with an initial reactivity nearly 50% that of kapton. The reaction of atomic oxygen with MoS/sub 2/ has little or no translational energy barier; i.e., thermally generated atomic oxygen reacts as readily as that having 1.5 eV of translational energy. It is also shown that water, present in the flowing afterglow apparatus used to study thermal O-atom reactivity, formed sulfates on the MoS/sub 2/ surface and that the sulfate is not likely in the form of sulfuric acid. These results imply that water dumps or outgasing in low earth orbit have the potential of forming sulfuric acid covered surfaces on MoS/sub 2/ lubricants. For MoS/sub 2/ films sputter-deposited at 50-70/degree/C, friction measurements show a high initial friction coefficient for O-atom exposed MoS/sub 2/ surfaces (up to 0.25) which drops to the normal low values after several cycles of operation in air and ultrahigh vacuum. For MoS/sub 2/ films deposited at 200/degree/C, the friction coefficient was not affected by the O-atom exposure. 11 refs., 3 figs.
- Research Organization:
- Los Alamos National Lab., NM (USA)
- DOE Contract Number:
- W-7405-ENG-36; AC04-76DP00789
- OSTI ID:
- 6090194
- Report Number(s):
- LA-UR-89-1883; CONF-890468-12; ON: DE89014241
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
CHALCOGENIDES
CHEMICAL REACTIONS
DIFFUSION
ELEMENTS
FILMS
FRICTION
MOLYBDENUM COMPOUNDS
MOLYBDENUM SULFIDES
NONMETALS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
THIN FILMS
TRANSITION ELEMENT COMPOUNDS