Molecular tribology of fluid lubrication - Shear thinning

Journal Article · Wed Jul 01 00:00:00 EDT 1992 · ASLE Transactions (American Society of Lubrication Engineers); (United States)

DOI:https://doi.org/10.1080/10402009208982135· OSTI ID:7242881

Carson, G; Hu, Hsuan-Wei; Granick, S ^[1]

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1. Illinois, University, Urbana (United States)

An investigation of the boundary layer viscosity of films of nonpolar liquid lubricants, hexadecane and a silicone oil, octamethyl-cyclotetrasiloxane, confined between parallel atomically smooth single crystals of muscovite mica, is reported. The effective viscosity (eta sub eff) showed a zone of linear response and a second zone of extreme shear thinning. In the zone of linear response, (eta sub eff) increased exponentially with increasing net normal pressure, increasing from 250 to 2200 poises as the pressure was raised from 0.03 to 0.15 MPa. However, very large shear thinning (decay by more than one order of magnitude) was observed as the effective shear rate was varied from 1/sec to 10,000/sec, and the transition to glassy solid response (critical shear stress behavior) was impeded by continuous shear. These experiments show that the rheology of a lubricant within a zone of contact can be strikingly different from that in the bulk. Possible engineering applications of these findings are discussed. 25 refs.

• OSTI ID: 7242881
• Journal Information: ASLE Transactions (American Society of Lubrication Engineers); (United States), Vol. 35:3; ISSN 0569-8197
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
LUBRICATING OILS
VISCOSITY
MUSCOVITE
SHEAR PROPERTIES
TRIBOLOGY
WEAR RESISTANCE
LUBRICANTS
MECHANICAL PROPERTIES
MICA
MINERALS
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
PETROLEUM PRODUCTS
SILICATE MINERALS
320302* - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Materials