In gear drives, lubricating oils or greases are usually used as an intermediate medium. They reduce wear and friction, dissipate heat, and transport contaminants away from the contact point. Since tooth flank contact has different tribological requirements than bearings or seals, heat dissipation in dry operation of highly stressed contacts is a key challenge. PVD solid lubricant coatings are designed to perform these tasks in dry tooth flank contact, thereby placing greater focus on the microtopography of the contact surfaces. The aim of the research project, which is being carried out as subproject 6 in collaboration with the Machine Tool Laboratory (WZL) at RWTH Aachen University, is the experimental and simulated investigation of the supply and transfer mechanisms of PVD solid lubricants for dry rolling contacts using the example of tooth flank contact. For this purpose, coated test specimens with different microtopographies are tested on the two-disc test bench under conditions typical for gears and characterized analytically and tribologically. 

This should provide a fundamental understanding of the processes involved in solid lubricant supply and transfer. Based on the findings, a method for tribosimulation of dry contacts will be developed. Finally, a load-appropriate coating system will be developed and the results will be transferred to real-life loaded tooth flank surfaces. Test gear teeth with optimized surfaces and coatings will be used to verify the accuracy of the predictions and the applicability of the method. 

Further information is available here.