In order to seek for a new ideal method to solve friction
abrasion and other interfacial effect problems in micro/nano electro mechanical system
the influence of graphite contact interfaces on graphite superlubricity and the sources of resistance were researched. First
the electron beam lithography
ion beam etching and other micro-processing methods were used to prepare microscale graphite mesa
and graphite surface with superlubricity was obtained by using micro-nano manipulator to shear the graphite mesa. Then
the Raman spectrum
nanoscale infrared spectrum and atomic force microscope were used to characterize the surface of the obtained superlubricity graphite. Finally
energy dispersive spectrometer was taken to analyze micro-area elements in graphite platform. The result shows that the surface of superlubricity graphite has atomically smooth flatness and has high order degree
but there are multiple defects on the edge of the graphite surface; and multiple molecules are absorbed on the surface of the graphite in the process of machining and in the atmospheric environment. The content of marginal oxygen atom is 24.2% higher than the content of in-plane oxygen atom. In the process of pushing graphite platform
the marginally absorbed molecule will hinder the relative sliding of contact interface of superlubricity graphite. Moreover
energy is needed to overcome the absorption of these molecules
which becomes the source of frictional resistance.
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references
ERDEMIR A, MARTIN J M. Superlubricity [M]. Amsterdam: Elsevier Science, 2007: 253.
EWEN J P, GATTINONI C, THAKKAR F M, et al.. Nonequilibrium molecular dynamics investigation of the reduction in friction and wear by carbon nanoparticles between iron surfaces [J]. Tribology Letters, 2016, 63(3): 38.
YAN H X, LI S, JIA Y, et al.. Hyperbranched polysiloxane grafted graphene for improved tribological performance of bismaleimide composites [J]. RSC Advances, 2015, 5(17): 12578-12582.
HIRANO M, SHINJO K. Atomistic locking and friction [J]. Physical Review B, 1990, (41): 11837.
SHARP T A, PASTEWKA L, ROBBINS M O. Elasticity limits structural superlubricity in large contacts [J]. Physical Review B, 2016, 93(12): 121402.
van WIJK M M, de WIJN A S, FASOLINO A. Collective superlubricity of graphene flakes [J]. Journal of Physics: Condensed Matter, 2016, 28(13): 134007.
KOREN E, DUERIG U. Superlubricity in quasicrystalline twisted bilayer graphene [J]. Physical Review B, 2016, 93(20): 201404.
DIENWIEBEL M, VERHOEVEN G S, PRADEEP N, et al.. Superlubricity of graphite [J]. Phys. Rev. Lett. 2004, (92): 126101.
LEE C, LI Q Y, KALB W, et al.. Frictional characteristics of atomically thin sheets [J]. Science. 2010, 328(5974): 76-80.
KOREN E, LÖRTSCHER E, RAWLINGS C, et al.. Adhesion and friction in mesoscopic graphite contacts [J]. Science, 2015, 348(6235): 679-683.
LIU Z, YANG J R, GREY F, et al.. Observation of microscale superlubricity in graphite [J]. Phys. Rev. Lett., 2012, 108(20):205503.
LIU Z, ZHANG S M, YANG J R, et al.. Interlayer shear strength of single crystalline graphite [J]. Acta Mechanica Sinica, 2012, 28(4):978-982.
YANG J R, LIU Z, GREY F, et al.. Observation of high-speed microscale superlubricity in graphite [J]. Phys. Rev. Lett, 2013, 110(25): 255504.
WANG W, DAI S Y, LI X D, et al.. Measurement of the cleavage energy of graphite [J]. Nature Communications, 2015, 6:7853.
DIETZEL D, FELDMANN M, SCHWARZ U, et al.. Scaling laws of structural lubricity [J]. Phy. Rev. Lett., 2013, 111(23): 235502.
VARINI N, VANOSSI A, GUERRA R, et al.. Static friction scaling of physisorbed islands: the key is in the edge [J]. Nanoscale, 2015, 7(5): 2093-2101.
VERZHBITSKIY I A, CORATO M D, RUINI A, et al.. Raman fingerprints of atomically precise graphene nanoribbons [J]. Nano letters, 2016, 16(6): 3442-3447.