Lubrication boundary layer

Application of an oily or greasy substance in order to reduce friction. If a layer of lubricant is thick enough, it reduces the coefficient of friction (/u). For a very thin layer of lubricant, boundary layer lubrication takes place. 

See also Beer s Law Boundary film lubrication regimes, 15 212 Boundary layer capacitors, carbon black application, 4 800... 

Boundary layer concept, 11 751-753 Boundary lubricity additives, 15 213, 224-225... 

Holinski, R., Dynamics of Boundary Layers, Lubric. Eng., 36, 530, (1980). Gresty, D.A., Kunz, E.J. and Risdon, T. J., The Effect of MoSj Based Lubricants on Automotive Gear Efficiency and Operating Temperatures, SAE Passenger Car Meeting, Detroit, (Sept. 1977). SAE Preprint No. 770834. 

Y. C. Kong, D. J. Tildesley and J. Alejandre, The Molecular Dynamics Simulation of Boundary-layer Lubrication, Mol. Phys. 92 (1997) 7-18. 

Tribological test results (macroscopic effects) and molecular descriptions of a boundary layer are joined together in one dependence using the a, model [16, 17]. The model is based on the application of system analysis to tribological systems. The model s main assumption is that due to the relationship between two functions f y) and (y), describing tribological processes in a given test, the coefficient o can be treated as a property of the lubricant which is not connected with only one tribotest as follows ... 

Slow moving slides and tables in machine tools are subject to jerky motion due to alternating slipping and sticking of the sliding surfaces. Consequently, specially developed lubricants are required to prevent and/or reduce the stick-slip phenomenon. Slideway oils usually contain polar surface-active compounds, mostly fatty acid derivatives, together with anti-wear additives and oxidation inhibitors. The polar surface-active agents form oriented boundary layers which prevent adhesive friction. 

The mechanisms of particle removal have been studied in the past few years. Reports show that the particles adhere to a surface primarily by van der Waals forces, electrostatic attraction, or capillary action.2 The cleaning is by hydrodynamic lubrication. The thickness of the hydrodynamic fluid layer, as estimated, was around 3.7 pm.1 On the contrary, numerical analysis concluded that the lift force in the hydrodynamic boundary layer of fluid was too small to lift particles off the surface.3 The possible removal force comes likely from the drag force between the brush and the wafer surface. Major... 

Modem lubricants combine (a) components favorable for fluid lubrication and (b) chemical compounds giving good boundary layer lubrication. 

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