Effects of ion implantation on microstructure, endurance and wear behavior of IBAD MoS{sub}2

摘要

Thin MoS{sub}2 coatings were prepared on steel and Si substrates via ion-beam assisted deposition using conditions known to produce dense, basal oriented micro structures. After deposition, the coated substrates were irradiated with 180 keV Ar{sup}(2+) ions at doses of 1 × 10{sup}15, 1 × 10{sup}16, and 5 × 10{sup}16 ions/cm{sup}2. Microstructures of as-deposited and ion irradiated MoS{sub}2 coatings were examined using X-ray diffraction, high resolution transmission electron microscopy, and micro-Raman spectroscopy. Friction, wear and endurance were examined under both unidirectional and reciprocating sliding conditions in dry air. The lowest ion irradiation dose altered the initial microstructure, producing basal oriented, nearly defect-free crystalline domains of MoS{sub}2 in an amorphous matrix; at the highest dose the coatings were nearly amorphous but the remaining MoS{sub}2 showed mixed orientation. Ion irradiation of the MoS{sub}2 coatings did not significantly modify the friction behavior, and only at the highest dose was the endurance altered, decreasing by more than 75%. Two changes in wear behavior were observed in the highest dosed coatings: (1) accelerated wear of the coating and (2) elimination of solid lubricant reservoirs. Destruction of the solid lubricant replenishment process resulted in premature failure of the highest dosed coating.