Tribological performance and deformation of sputter-deposited MoS₂ solid lubricant films during sliding wear and indentation contact

Abstract

Microstructural aspects of the plastic deformation of sputter-deposited MoS₂ solid lubricant films on 440C bearing steel are presented. The films were produced in three different laboratories using r.f., d.c. and r.f. magnetron sources. Two types of contact were investigated: (1) sliding wear contact in a thrust-washer apparatus used to evaluate film tribological performance and (2) brale indentation contact used to investigated cross-sectional morphology and adhesion. Scanning electron microscopy, X-ray diffraction, Auger electron spectroscopy and X-ray photoelectron spectroscopy were used to characterize the films. The as-deposited morphology was found to influence the initial nature of the wear debris and the load-bearing capabilities of the films. In many cases a highly deformed region confined to the surface of the films was found. Applied stress reoriented crystallites and induced crystallization, the degree of both processes being related to the initial structure and the percentage of wear lifetime of the film.