Conjecture and paradigm on limits of boundary lubrication

A multi-scale approach from mono-molecularly smooth cobalt surfaces coated with mono-layers of fatty acids to industrially manufactured parts lubricated with additivated oil is presented to focus on the limits of boundary lubricated dynamic interfacial systems. Based on these experimental results, a critical review of the current state of knowledge regarding the limits of boundary lubrication is performed. In the analysis of the activation of catastrophic wear, rheological (residual stresses, hardness), morphological (amplitude, horizontal and hybrid) and physical-chemical (surface free energy and its components) properties are considered. On this basis, the authors formulated conjectures and a paradigm related to the initiation of catastrophic wear considering multi-physics phenomenology.