Ultra-mild wear in gears requires tribological surface layers which form during operation when oil additives are present in the lubricant. Zinc-dialkyldithiophosphates (ZDDP) are the most frequent anti-wear additives. The improvement of current additives and the design of next-generation additives requires a thorough understanding of the tribolayer formation mechanisms of ZDDP. To that end, a reduction of the multitude of influencing parameters is required to reach the fundamental understanding.
The present contribution describes novel cyclic contact setup at the microscale that have a limited number of parameters and that result in chemically and topologically similar tribological surface layers. The new setup for room temperature experiments shows that compression even with limited shear driven flow creates surface layers.