The Study of the Dynamic Thickness of Organic Boundary Films Under Metallic Sliding Contact

The paper herein proposes a method to simultaneously measure the friction, wear, and thickness of boundary films under a pure sliding contact between metallic surfaces. The method is based on the capacitance method used by Crook and Dyson et al. to measure elastohydrodynamic film thicknesses. Pilot tests conducted on sunflower oil using the new method showed an appreciable growth in the boundary film thickness, with a corresponding drop in the coefficient of friction. Very little wear was observed during the film growth. It is postulated that this growth was due to the polymerization of the unsaturated fatty acid chains.

[1]  Hugh Spikes,et al.  The Measurement and Study of Very Thin Lubricant Films in Concentrated Contacts , 1991 .

[2]  D. Boda,et al.  Relative permittivity of polar liquids. Comparison of theory, experiment, and simulation. , 2005, The journal of physical chemistry. B.

[3]  D. Mcclements,et al.  Role of Physical Structures in Bulk Oils on Lipid Oxidation , 2007, Critical reviews in food science and nutrition.

[4]  Hugh Spikes,et al.  Direct Observation of Boundary Layers , 1996 .

[5]  G. M. Acosta,et al.  High-Pressure PVT Behavior of Natural Fats and Oils, Trilaurin, Triolein, and n-Tridecane from 303 K to 353 K from Atmospheric Pressure to 150 MPa , 1996 .

[6]  S. M. Hsu.  Boundary lubrication: current understanding , 1997 .

[7]  Stefan Björklund,et al.  A finite element-based model of normal contact between rough surfaces , 2003 .

[8]  F. P. Bowden,et al.  The Friction and Lubrication of Solids , 1964 .

[9]  R. Gohar,et al.  Optical Measurement of Oil Film Thickness under Elasto-hydrodynamic Lubrication , 1963, Nature.

[10]  P. Wong,et al.  Pressure and temperature dependence of the density of liquid lubricants , 1996 .

[11]  S. Bair.  Rheology and high-pressure models for quantitative elastohydrodynamics , 2009 .

[12]  S. K. Biswas,et al.  Frictional response of fatty acids on steel. , 2009, Journal of colloid and interface science.

[13]  H. Spikes.  The borderline of elastohydrodynamic and boundary lubrication , 2000 .

[14]  H. Sakamoto,et al.  Lubricating properties of vegetable oils and paraffinic oils with unsaturated fatty acids under high‐contact‐pressure conditions in four‐ball tests , 2003 .

[15]  L. Onsager.  Electric Moments of Molecules in Liquids , 1936 .

[16]  Q. Xue,et al.  The tribological behaviors of ordered system ultrathin films , 2003 .

[17]  A. W. Crook.  The lubrication of rollers , 1958, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[18]  S. Wen,et al.  Thin film lubrication. Part I. Study on the transition between EHL and thin film lubrication using a relative optical interference intensity technique , 1996 .

[19]  M. Furey.  The formation of polymeric films directly on rubbing surfaces to reduce wear , 1973 .

[20]  S. M. El-Shami,et al.  Dielectric properties for monitoring the quality of heated oils , 1992 .

[21]  Hugh Spikes,et al.  The development and application of the spacer layer imaging method for measuring lubricant film thickness , 2001 .

[22]  S. Sundararajan,et al.  Boundary lubrication properties of lipid-based compounds evaluated using microtribological methods , 2006 .

[23]  G. Biresaw.  Elastohydrodynamic properties of seed oils , 2006 .

[24]  B. Bhushan,et al.  Introduction to Tribology , 2002 .

[25]  H. Naylor,et al.  Paper 10: The Measurement of Oil-Film Thickness in Elastohydrodynamic Contacts: , 1965 .