Their unstable lubricant behavior depends on the chemical structure of functional end-groups and molecular weight.
In this paper, we focus on the lubricant behavior only, in the operating conditions of foil bearings.
Nano-lubricant behavior is diagnosed by using the Herschel-Bulkley (type Bingham) model, so that in temperatures < 45 °C, nano-lubricant shows non-Newtonian behavior of Bingham pseudoplastic, and it shows Bingham plastic non-Newtonian behavior at temperatures above 45 °C.
The thick water layers within the chains serves as boundary lubricants, and this is thought to be the molecular origins of lubricating behavior.
In the literature, it has been suggested that crumpled graphene is analogous to wadding paper, and that this morphology significantly improves self-dispersion in lubricants and anti-wear behavior.
Therefore, refrigerant-lubricated foil bearings behavior is studied, including the likelihood of two-phase flow in the lubricant.
With the graphite lubricant present, the frictional behavior ranged from levels similar to the TiN coating alone, to that of graphite alone.
In the present study, we focus on the shear-thinning behavior of a lubricant that was induced by confinement and attempt to clarify the effect of shear-thinning on the gap dependence of viscoelasticity.
These multilayer coatings were investigated with regard to their morphology and composition as well as indentation hardness, abrasive wear, lubricant free friction and wetting behavior via contact angle measurements.
Even more, if the threshold value of shear stress τl, which characterizes the transition from Newtonian to non-Newtonian behavior of the lubricant, is sufficiently small the annular pressure peak may even disappear.
