Characterization of wear debris of systems operated under low wear-rate conditions

Wear particles found in ultra-low wear rate experiments were analyzed in order to understand the wear mechanism. Using a sophisticated particle separation method, the debris were separated from the oil and then analyzed using transmission electron microscopy accompanied by electron diffraction for chemical characterization. The majority of the wear particles have a size of about 250 nm, only very few are larger than 1 μ m. The particles appear mostly amorphous and contain chemical elements of both interacting solids as well as the oil. In addition, almost all particles have a thickness of 30 nm or less. The proposed particle generation mechanism is a squeezing process of flowed material under pressure.