Investigation of tribological properties of solid film lubricants under different environmental conditions

Reduce friction and wear on both surfaces in contact with each other in order to minimize damage to the surfaces of the viscous fluid is considered to be the ideal solution to separate. But in some cases is not possible to avoid the contact surfaces. In addition, mechanical systems may have to work under such conditions like high-temperature, overload, vacuum, low operating speeds and so on that we call extreme conditions. One of the methods to minimize losses in such cases, the tribological use of solid lubricants. With their layered crystal lattice structure of the solid lubricant trace a successful tribological results. Solid lubricants can be used alone or additive for liquid lubricants. In this study, 10mm in diameter and 20mm length made of AISI 1008 steel samples coated with graphite and MoS2 powders which widely used today as a solid lubricant with lead-spinning method. The samples tested by pin-disc type tribometer device that CAD designed and manufactured. Use the disk surface hardening process, the device has a hardness of 55 HRC AISI 1040 steel. Experiments did in three different environment which are dry, oil and oil + MoS2 additive. 80W gear oil is used as an oil. As a result, MoS2 and graphite coating decrase the surface friction resistance at 50-70% for dry environment. In the oil environment MoS2 in have a better coefficient of friction than graphite. Participating as a contribution to the oil into the graphite coating gave better results due to synergy effects MoS2. According to the test results of the samples a statistical analysis was conducted for wear. As a result, wear life of MoS2 and graphite samples calculated for 95% reliability of the system.