NASA Logo

NTRS - NASA Technical Reports Server

Back to Results
Surface Chemistry, Friction, and Wear Properties of Untreated and Laser-Annealed Surfaces of Pulsed-Laser-Deposited WS(sub 2) CoatingsAn investigation was conducted to examine the surface chemistry, friction, and wear behavior of untreated and annealed tungsten disulfide (WS2) coatings in sliding contact with a 6-mm-diameter 440C stainless-steel ball. The WS2 coatings and annealing were performed using the pulsed-laser-deposition technique. All sliding friction experiments were conducted with a load of 0.98 N (100 g), an average Hertzian contact pressure of 0.44 GPa, and a constant rotating speed of 120 rpm. The sliding velocity ranged from 31 to 107 mm/s because of the range of wear track radii involved in the experiments. The experiment was performed at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7X(exp -10) Pa), dry nitrogen (relative humidity, less than 1 percent), and humid air (relative humidity, 15 to 40 percent). Analytical techniques, including scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), x-ray photo electron spectroscopy (XPS), surface profilometry, and Vickers hardness testing, were used to characterize the tribological surfaces of WS2 coatings. The results of the investigation indicate that the laser annealing decreased the wear of a WS2 coating in an ultrahigh vacuum. The wear rate was reduced by a factor of 30. Thus, the laser annealing increased the wear life and resistance of the WS2 coating. The annealed WS 2 coating had a low coefficient of friction (less than O.1) and a low wear rate ((10(exp -7) mm(exp 3)/N-m)) both of which are favorable in an ultrahigh vacuum.
Document ID
19970009635
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Miyoshi, Kazuhisa (NASA Lewis Research Center Cleveland, OH United States)
Wheeler, Donald R. (NASA Lewis Research Center Cleveland, OH United States)
Zabinski, Jeffrey S. (Wright Lab. Wright-Patterson AFB, OH United States)
Date Acquired
September 6, 2013
Publication Date
December 1, 1996
Subject Category
Nonmetallic Materials
Report/Patent Number
NASA-TM-107342
E-10351
NAS 1.15:107342
Report Number: NASA-TM-107342
Report Number: E-10351
Report Number: NAS 1.15:107342
Accession Number
97N15031
Funding Number(s)
PROJECT: RTOP 505-63-5A
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available