Wear inhibitors and rheology of lubricants
confined to nano-separation between two surfaces

Yanhua Zhou, Tahir Cagin, William A. Goddard III

Materials and Process Simulation Center, Caltech

Elaine S. Yamaguchi, Andrew Ho

Chevron Chemical Company, Oronite Technology Group

Yongchun Tang

Chevron Petroleum Technology Company

    To understand the mechanism by which a wear inhibitor additive in a base oil prevents wear of an engine surface, we studied dithiophosphates (DTP) bound to the Fe2O3-(0001) surface under a shear flow condition, using computer simulations. The shear flow is generated by moving a top surface at a constant speed and keeping a bottom surface stationary. Each surface is covered by a self-assembled monolayer of DTP molecules. Between them filled with a lubricant film (Figure1, postscript).


    We have carried out the simulations at a speed of 1 A/ps and separation of 40 A. The interesting results are summarized as follows.

Acknowledgement

    This research was supported by the Chevron Chemical Company (Oronite Technology Group) and grants from the DOE-BCTR and NSF (CHE 95-12279). We thank Larry Smarr for access to the NCSA system for some calculations.



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