25, 1149 (1982), Ji, L., Li, H., Zhao, F., Quan, W., Chen, J., Zhou, H.: Atomic oxygen resistant behaviors of Mo/diamond-like carbon nanocomposite lubricating films. The ultra-low friction coefficient (typically 10- 2 range) of MoS 2 -based coatings is generally associated with friction-induced orientation of "easy-shear" planes of the lamellar structure parallel to the sliding direction, particularly in the absence of environmental reactive gases and with moderate normal loads. 14, 46284633 (2014), Gao, J., et al. In digital electronics, transistors control current flow throughout an integrated circuit and allow for amplification and switching. MoS2 is also used in CV and universal joints. : Special points for Brillouin-zone integrations. Tribological properties of MoS2 coating for ultra-long wear-life and low coefficient of friction combined with additive g-C3N4 in air. [58][59], In 2017 a 115-transistor, 1-bit microprocessor implementation using two-dimensional MoS2. : Reactive molecular dynamics study of Mo-based alloys under high-pressure, high-temperature conditions. MoS 2 also has greater load-carrying capacity and its manufacturing quality is better controlled. Tribological properties of MoS2/C coatings with different carbon contents (44.784.3 at.%) deposited by magnetron sputtering were systematically investigated under atmospheric environment. The exact mechanism of cleavage was found to be layer dependent. Trans. 21, 24262431 (1982), Serpini, E., et al. Catal. Her research areas cover basic and application research of solid lubrication, wear-resistant, and protective film/coating materials. 2023 Springer Nature Switzerland AG. The aforementioned scheme is good for graphene only. : Impact of microstructure on MoS2 oxidation and friction. The low shear strength and subsequently low friction coefficients of MoS2 are a result of its lamellar structure, where basally oriented, molecularly thin lamellae with sulfur-terminated surfaces interact predominantly through weak van der Waals forces. Mater. Lett. Unless otherwise noted, experiments were performed in a dry N2-filled glovebox (<10ppm O2 and<10ppm H2O), using a chilled mirror hygrometer to measure humidity. Interactions between water molecules and unterminated edges of MoS2 lamellae have also been suggested as an impediment to low-strength shear [33]. The calculation was not spin polarized. provided correct acknowledgement is given. : The effects of hertzian stress and test atmosphere on the friction coefficients of MoS2 coatings. 3df and 4b, e) where the work function was shown to gradually increase as the relatively thick, effectively bulk, film is run in and the thickness of the oriented surface film increased. Experiments in humid N2 consistently led to higher friction than those in dry N2 (Fig. Xiaohong LIU. Rev. ACS Appl. As in prior literature [58], these MoS2 films obeyed Hertzian contact mechanics, with friction coefficients that were inversely proportional to contact force. [2], MoS2 is naturally found as either molybdenite, a crystalline mineral, or jordisite, a rare low temperature form of molybdenite. J. Vac. This is not likely a concern when comparing to simulation results, as wear during the first few cycles of sliding has been shown to remove the oxidized surface film, eventually leading to a recovery of low friction by the formation of ordered films and transfer films on the countersurface [45, 63]. Coefficient of Friction | Engineering Library - 146.59.90.208. 1. AU - Shiota, Ichiro. Research has been conducted on compacted oxide layer glazes, which form during metallic surface sliding wear at several hundred degrees Celsius. volume65, Articlenumber:79 (2017) Friction and wear test results revealed that the friction coefficient and wear rate of a 3 wt% MoS2-MWCNT-1 filled polyurethane composite coating were reduced by 25.6% and 65.5%, respectively. Pressure Vessel 68, 33993406 (1964), Uemura, M., Saito, K., Nakao, K.: A mechanism of vapor effect on friction coefficient of molybdenum disulfide. : An updated overview of diamond-like carbon coating in tribology. RSC Adv 5(79): 6425464260 (2015), Zhu L, Wang Y, Hu F, Song H J. : The effect of humidity on low-load frictional properties of a bonded solid film lubricant. (a) Oleic acid; (b) Atlantic spindle oil (light mineral); (c) castor oil; (d) lard oil; (e) Atlantic spindle oil plus 2 percent oleic acid; (f) medium mineral oil; (g) medium mineral oil plus percent oleic acid; (h) stearic acid; (i) grease (zinc oxide base); (j) graphite; (k) turbine oil plus 1 percent graphite; (l) turbine oil plus 1 percent stearic acid; (m) turbine oil (medium mineral); (n) olive oil; (p) palmitic acid; (q) ricinoleic acid; (r) dry soap; (s) lard; (t) water; (u) rape oil; (v) 3-in-1 oil; (w) octyl alcohol; (x) triolein; (y) 1 percent lauric acid in paraffin oil. The strain at failure ranges from 6 to 11%. ACS Appl Mater Interfaces 9(33): 2801928026 (2017), Donnet C, Martin J M, Le Mogne T, Belin M. Super-low friction of MoS2 coatings in various environments. We observe this relationship in our experiments in dry N2, but not humid N2. It is widely used as a dry lubricant because of its low friction and robustness. Thin Solid Films 154, 309322 (1987), Lince, J.R., Fleischauer, P.D. Tribol. In macroscale contacts, edges of MoS2 lamellae at the surface are likely oxidized prior to testing, further enhancing interactions with water [15, 24, 38,39,40]. If you want to reproduce the whole 7, 15641583 (1992), Ferrari, A.C., Robertson, J.: Interpretation of Raman spectra of disordered and amorphous carbon. 5). Li JI. Lubricat Eng (1): 6163 (2006), Xuan Y, Liu Y, Zhao X C, Cheng J W, Li Y J, Li J G. The investigation of the tribological properties of AlOOH and Fe3O4 nanoparticles as additives in liquid paraffin. Paste Benefits Moly Fortification Explained Molybdenum Disulfide is an ideal lubricant because of its familiar crystalline structure which allows molecules to shear, creating an exceedingly low coefficient of friction between coated surfaces. [16] While Scotch tape is generally used as the adhesive tape, PDMS stamps can also satisfactorily cleave MoS2 if it is important to avoid contaminating the flakes with residual adhesive. Technol. Coat. 5(3), 036415 (2018), Costa-Amaral, R., Forhat, A., Caturello, N.A.M.S., Silva, J.L.F.D. MoS2 is effective for the hydrogenation of nitro compounds to amines and can be used to produce secondary amines via reductive amination. For example, the work function of MoO3 is typically 2eV higher than that of MoS2, well above the measured increase of 0.10.25eV observed in the wear scars in our experiments. The friction on atomically thin MoS2 deposited on a SiO2/Si substrate is reduced almost five times to achieve an ultra-low friction state (coefficient of friction nearly 0.0045) by rubbing the surface with an AFM tip under the electric field. 2. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in Int. Soc. 1 Introduction As solid lubricant coatings, transition metal dichalcogenides (TMDs) such as MoS 2 and WS 2 are promising candidates for applications in fields of high vacuum, aerospace, where liquid lubrication is prohibited or not available [ 1 ]. ACS Appl. Technol. Phys. 100, 093719 (2006), Singer, I.L., Bolster, R.N., Wegand, J., Fayeulle, S., Stupp, B.C. These values are smaller than that for a continuous monolayer of MoS2 (5.69eV), and the work function further increases to 5.94eV for both 3- and 4-layer systems (Fig. B 61, 1409514107 (2000), Stoyanov, Pantcho, Stemmer, Priska, Jarvi, Tommi T.: Friction and wear mechanisms of tungstencarbon systems: a comparison of dry and lubricated conditions. Wear 237, 186196 (2000), Zabinski, J.S., Donley, M.S., McDevitt, N.T. Surf. Sci. : Effect of substrate surface finish on the lubrication and failure mechanisms of molybdenum disulfide films. Lett. Rep. 5, 10505 (2015), Berg, M., et al. Mater. This effect is visible in Fig. The vacuum energy is computed from a 1D averaged electrostatic potential based on the 3D potential output from VASP using the postprocessing utility from Walsh and Catlow [53]. [32] With butyl lithium, the product is LiMoS2. U1637204, 41663012, 51775537, and 51775533), the program of the Light of the Chinese Academy of Science in Chinas Western Region (2015), and the Chinese Academy of Science and its Youth Innovation Promotion Association (2016368) for financial support. permission is not required) please go to the Copyright This approach can provide an additional channel to achieve ultra-low friction on MoS2 related two-dimensional materials with semiconductor properties. 65, 64 (2017), Lancaster, J.K.: A review of the influence of environmental humidity and water on friction, lubrication and wear. Lett. Chem. : Hertzian stress contribution to low friction behavior of thin MoS2 coatings. We report an investigation of the friction mechanisms of MoS2 thin films under changing environments and contact conditions using a variety of computational and experimental techniques. Microindentation experiments on nanopillars of Cr-doped MoS2 found that the yield strength increased from an average of 821 MPa for pure MoS2 (at 0% Cr) to 1017 MPa at 50% Cr. : Layer dependence of the electronic band alignment of few-layer MoS2 on SiO2 measured using photoemission electron microscopy. Lett. 3(a), as the load increased, the friction coefficient decreased rapidly and fell below 0.1 at a load of 1.0 GPa. Work function changes on the surface of MoS2 wear tracks suggest that the lamellae size and thickness of basally oriented material are strongly influenced by the presence of contaminants that effectively restrict coalescence and formation of larger, ordered MoS2 lamellae. Each sulfur atom has pyramidal coordination and is bonded to three molybdenum atoms. Molybdenum Disulfide can provide a low coefficient of friction, sometimes as low as 0.05 COF. friction. The exchange correlation was treated with the PBE functional [48], and dispersion corrections were added using the DFT-D3 method from Grimme [49, 50] using Becke-Johnson damping. The solid lubricant MoS2 demonstrates excellent lubricating properties, but it spontaneously oxidizes and absorbs moisture in air, and thus results in poor wear resistance and short wear-life. - 92.243.17.49. Rev. The origin of super-low friction coefficient of MoS2 coatings in Interfaces 5, 61236135 (2013), Goasa, K., Grzeszczyk, M., Leszczynski, P., Faugeras, C., Nicolet, A.A.L., Wysmoek, A., Potemski, M., Babinski, A.: Multiphonon resonant Raman scattering in MoS2. Lett. 2a). Appl. Hongxuan LI. Tungsten Disulfide (WS2) can also be used in high temperature and high pressure applications. 57, 995997 (1990), Gul, A., Bacaksiz, C., Unsal, E., Akbali, B.: Theoretical and experimental investigation of conjugation of 1, 6-hexanedithiol on MoS2. : The detrimental effect of exposure to air on supported MoS2. 4, 17 (2020), Hao, G., et al. 701, 121700 (2020), Scharf, T.W., Goeke, R.S., Kotula, P.G., Prasad, S.V. Int. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. Technol. Lett. Res. Technol. Nano Lett. The tribological community has made significant progress in understanding the independent and combined roles of water and oxygen in this degradation in tribological performance over time (i.e., aging behavior) of MoS2 contacts [16, 17]. Fetching data from CrossRef. Sci. This broadening due to the measurement resolution was corrected for post facto by shifting the edges of the spectra, similar to the procedure outlined in Yi et al. Send Inquiry Product Details Inquiry MoS2 Friction Modifier Molybdenum Disulfide introduce: Commun. He obtained his bachelor in chemical and pharmaceutical from Chengdu University of Technology in 2014. Sliding friction tests of MoS2 using a pin on disc tester at low loads (0.12 N) give friction coefficient values of <0.1. 73, 152159 (1995), Wahl, K.J., Dunn, D.N., Singer, I.L. (eds.) If you are the author of this article, you do not need to request permission to reproduce figures He is currently studying the lubrication mechanism of 2D nanomaterials in the wear and surface engineering research group at Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (LICP-CAS), China. Adv. DFT calculations of the work function ofMoS2 lamellae for monolayer lamellae of increasing size and continuous MoS2 lamellae with increasing layers. In appearance and feel, molybdenum disulfide is similar to graphite. : Bandgap, mid-gap states, and gating effects in MoS2. Surf. HVAC Systems Calcs Appl. 17, 389397 (2004), Article J. Chem. The energy cutoff was 520eV, equal to 1.3 times the largest ENMAX value for any of the pseudopotentials. 35, 1723 (2009), Vasenkov, A., et al. and diagrams provided correct acknowledgement is given. In fact, adsorbed vapors may actually result in a slight, but insignificant, increase in 1d. Corrosion resistant steel or nickel base alloys/silver plated materials. It is the principal ore from which molybdenum metal is extracted. ACS Appl. Coefficient of Friction Equation and Table Chart - Engineers Edge Friction and wear mechanisms in MoS2 - ScienceDirect 108, 131601 (2016), Lince, J.R., Loewenthal, S.H., Clark, C.S. Spring Design Apps [22], The wear resistance of MoS2 in lubricating applications can be increased by doping MoS2 with Cr. 112, 013511 (2012), Curry, J.F., et al. This relationship is also borne out in our DFT calculations, where smaller lamellae exhibit lower work functions (4.79eV) than larger lamellae (5.02eV), and both are lower than the work functions of continuous monolayers and bulk MoS2 (5.695.94eV, Fig. Bell, M.E., Findlay, J.H. It is unaffected by dilute acids and oxygen. The results show that nanolubricant with 0.01 wt% MoS2 concentration showed the coefficient of friction, average wear scar diameter decreased by 19.24% and 19.52%, respectively, compared to the . Wear 165, 103108 (1993), Zabinski, J.S., Donley, M.S., Walck, S.D., Schneider, T.R., McDevitt, N.T. Lubrication Data Apps J Solid State Chem 252: 4371 (2017), Chen Z Y, Yan H X, Liu T Y, Niu S. Nanosheets of MoS2 and reduced graphene oxide as hybrid fillers improved the mechanical and tribological properties of bismaleimide composites. These systems were equilibrated for 100ps before atmospheric molecules were removed and the upper MoS2 layers replaced for further shear. : The effects of environmental water and oxygen on the temperature-dependent friction of sputtered molybdenum disulfide. Appl. Lett. Dig J Nanomater Biostruct 13(3): 731741 (2018), Duan C J, Yuan D M, Yang Z H, Li S, Tao L M, Wang Q H, Wang T M. 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The Vienna Ab initio Simulation Package (VASP) v5.4.4 [46, 47] was used with the standard PAW_PBE pseudopotentials packaged with VASP (Mo: 08Apr2002 and S: 06Sep2000). Appl. MoS2 is also used in ski wax to prevent static buildup in dry snow conditions and to add glide when sliding in dirty snow. Int. Lett. Practically, however, the surface of sputtered MoS2 films exposed to air are expected to be fully terminated, for example by oxygen (i.e., MoO2, MoO3). Rep. 7, 9576 (2017), Krger, M., et al. The ultra-low friction state of atomically thin MoS2 could attribute to the electronic tight-binding between MoS2 and the SiO2/Si substrate, which suppresses the atomic-scale deformation and limits the local pinning capability of MoS2. Mater. Micromechanical exfoliation, also pragmatically called "Scotch-tape exfoliation", involves using an adhesive material to repeatedly peel apart a layered crystal by overcoming the van der Waals forces. Coat. 17, 419428 (2004), Wahl, K.J., Seitzman, L.E., Bolster, R.N., Singer, I.L. Res. As in graphene, the layered structures of MoS2 and other transition metal dichalcogenides exhibit electronic and optical properties[48] that can differ from those in bulk. Phys. Atomically thin two-dimensional molybdenum disulfide (MoS 2) is well known for its excellent lubrication characteristics and is usually used as a solid lubricant in diverse micro/nanoelectromechanical systems (MEMS/NEMS).The friction on atomically thin MoS 2 deposited on a SiO 2 /Si substrate is reduced almost five times to achieve an ultra-low friction state (coefficient of friction nearly 0. . Frontiers | Interlayer Friction in Graphene/MoS2, Graphene/NbSe2 Previous work by our group showed that the surface microstructure (i.e., crystallite or lamellae size and thickness of the oriented layer) has a significant impact on friction behavior and its evolution in the presence of various vapor species, including water and molecular oxygen. 105, 175183 (1998), Lince, J.R.: Tribology of co-sputtered nanocomposite Au/MoS2 solid lubricant films over a wide contact stress range. The results showed irreversible deformation of MoS2 was caused by heavy load or high shear velocity during the friction process and the interlayer velocity changed from a linear to a ladder-like distribution; thus, the number of shear surfaces and the friction coefficient decreased. Structural and friction characteristics of g-C3N4/PVDF composites. Peiling Ke or Aiying Wang. According to the direct methods of shear strength's measurement, the value is near 25.3 MPa. In situ formation of spherical MoS2 nanoparticles for ultra-low friction. 1e, the defect-free systems exhibited the lowest friction coefficients. MRS Commun. Each element in a friction material formulation has its own role such as to improve fade resistance, control the friction coefficient, reduced porosity, and noise, increased strength, etc a small change in elemental composition varies the physical, mechanical and Tribological properties of the brake pads. B 13, 51885192 (1976), Larsen, A.H., et al. 57, 995997 (1990), Al Mahmud, K.A.H., Kalam, M.A., Masjuki, H.H., Mobarak, H.M., Zulkifli, N.W.M. 1). Surf. Gaussian smearing was employed with a sigma value of 0.05, and the k-points were treated using a 441 MonkhorstPack grid [51]. Phys. : Fundamental aspects of the electronic structure, materials properties and lubrication performance of sputtered MoS2 films. ACS Appl Mater Interfaces 5(3): 10031008 (2013), Hou K M, Han M M, Liu X H, et al. : Applications of space tribology in the USA. The lubricant is applied by burnishing and the excess is wiped from the bearing surface. Mater. Molybdenum disulfide is the inorganic compound with the formula MoS2. Those where stoichiometry is preserved by removal of selective sulfur atoms from the edges of the lamellae are not fully passivated, and therefore defective and referred to as such. The electric field leads to a shift and accumulation of charges at the interface between MoS2 and the SiO2/Si substrate. These experimental results corroborate trends observed in simulations showing that water prevents coalescence of small lamellae and their assembly into larger lamellae, ultimately resulting in higher friction coefficients(Fig. : Tribological behaviour and wear mechanism of MoS2Cr coatings sliding against various counterbody. J. Phys. Dalton Trans 43(17): 62956299 (2014), Wang J, Liu J L, Chao D L, Yan J X, Lin J Y, Shen Z X. Self-assembly of honeycomb-like MoS2 nanoarchitectures anchored into graphene foam for enhanced lithium-ion storage. B 59, 17581775 (1999), Kresse, G., Furthmller, J.: Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Lett. On the first pass, z was measured via PeakForce Tapping, while on the second pass, VCPD was measured by retracing the topography at a user-defined height and varying the DC sample voltage VDC to null the cantilever oscillations (VDC=VCPD when the tip-sample electrostatic force gradient was minimized). Coat. coefficient, but, unlike graphite, it does not rely on adsorbed vapors or moisture. : Space environmental effects on MoS2 and diamond-like carbon lubricating films: atomic oxygen-induced erosion and its effect on tribological properties. This black crystalline sulfide of molybdenum occurs as the mineral molybdenite. Friction coefficient for stainless steel and ice on polycrystalline ice as a function of temperature, [3].