Comparison between Synthetic Oil Lubricants for Reducing Fretting Degradation in Lightly Loaded Gold-Plated Contacts

This paper presents a comparison between the performances of two chemistries of synthetic oil lubricants, polyalphaolefins (PAOs) and perfluoropolyethers (PFPEs) when applied on gold-plated electrical contacts operating at contact loads of 9.8 cN and experiencing fretting-induced degradation. Performance assessment was done using the contact resistance and coefficient of friction behavior and the surface’s response to fretting in the presence of different types of lubricants within the two chemistries. It was found that the PAOs improved the fretting performance of the lightly loaded contacts, and statistically, were at least fifty times more reliable for a longer duration of fretting cycles than the PFPEs, suggesting their suitability for low contact load applications. At low loads, PFPEs underwent contact separation due to hydrodynamic lubrication, and the behavior was more observable among the PFPEs having higher kinematic viscosities. On the contrary, viscous PAOs had improved fretting performance and delayed time to contact failure than less viscous PAOs. The applied lubricant film thickness also contributed to the contact’s performance, and it was found that increasing the thickness of the PFPE films advanced contact failures, while the PAO film postponed contact’s time to failure.

THE ESTIMATION OF GEARS CONTACT FAILURES OVER THE TOOTH SURFACES

The article deals with the generalized classification of gears failures with detailed analysis of failures types in the contact fatigue of gears working surfaces and the development of the contact fatigue process. The criteria of the contact failure estimation of the gears working surfaces in failure of tooth surface are analyzed. The tests for the contact fatigue for the experimental models are conducted. The cycle operating dependence of pitting level over the working surfaces in depth of dimples is defined on basis of tests.