Nanomaterials in Tribology A Tutorial

Transcription

1 Nanomaterials in Tribology A Tutorial Hong Liang (hliang@tamu.edu) Mechanical Engineering Texas A&M University Presented at the Nanotribology Tutorial/Panel Session STLE/ASME International Joint Tribology Conference October 20-22, 2008, Miami, Florida, USA 1

2 Acknowledgements Dr. Subrata Kundu, TAMU 2

3 Outline Brief Introduction to Nanomaterials Nanomaterials in tribology as friction modifier for anti-wear Future trend 3

4 Nanomaterials are made into various forms ICD 4

5 Methods of synthesis Force Physical Process Physical Process Bulk Metal Chemical Process Metal Particles Chemical Process M n+ Reduction (n-1)+ M + M o Nanoparticles formation by physical and chemical processes High surface to volume ratio Top-down vs. bottom-up method 5

6 Synthesis methods Michael Faraday RSC, London Gustav Mie M. Faraday (1857) I st prepared colloidal gold using phosphorous in CS 2 and the pink color solution is still stable and kept in RSC, UK Vapor transport Wet chemical method Photoactivation (UV-light) γ-radiolysis technique Laser pulse technique Sonochemical method Kundu et al., New J Chem. 2003, 27, 656. & J. Phys. Chem. B. 2005, 109, M. Faraday, Philos. Trans. 1857, 147, 145. G. Frens, Nature 1973, 241, 20. West et al., PNAS., 2003, 100,

7 Step-1 Nucleation Step-2 Growth M n+ + ne = M 0 metal Reduction Metal Ion Metal (0) M n+ M n+ M n+ M n+ Reduction 7

8 Step-3 Stabilization Stabilizer: Surfactants Micelle Reverse Micelle Polymers Without Stabilizer W it h S ta b iliz e r PAH = PSS = Agglomeration Stabilization Thiol : Brust et al., Chem. Comm., 1994, 801. Dendrimer : Esumi et al., Langmuir, 2000, 16, Surfactants: Kundu et al., J. Am. Chem. Soc., 2005, 127,

9 Gold nanorods El-Sayed (GT), Murphy (USC), Mirkin (NWU), Yang (UCB), Kundu & Liang (TAMU) 9

10 Tribomaterials Nanoparticulates Thin films/layers Nanocomposites Friction reduction Anti-wear Lubricant additives 10

11 Crystal structures of materials Buckyball graphite diamond Single Layer Graphene Symmetric Double Layer Graphene Asymmetric Double Layer Graphene Ohta and Bostwick et al., Science, (2006) 11

12 Layered structures for lubrication MoS2 TiS2 WS2 12

13 Materials SWNT E (TPa) 1 to 5 Tensile Strength (GPa) Elongation at Break (%) 16 MWNT Comparison of Mechanical Properties [26][27][28][29][30][31][32] 150 BN 1.2 GaN WS Stainless Steel ~0.2 ~ Kevlar ~0.15 ~3.5 ~2 13

14 As a solid lubricant for self-lubricating A Si 3 N 4 ball against Al 2 O 3 flat. (a) Without film; (b) with NPs. Rapoport, Nanosci. & Nanotech.,

15 As a thinfilm Cardinal & Liang et al., submitted. 15

16 As additives to base fluids Fullerene C 60 ; Hydroxylated Fullerene C 60 (OH) 24, Crown Ether 16

17 As additives to base fluids 0.8 Water Friction Coefficient Crown Ether Fullerene Speed*Viscosity/Load Pendleton and Liang et al., in review. 17

18 Tribo-reactions in NPs Before test After test Crown Ether Fullerene Pendleton and Liang et al., JNR, (2009). 18

19 Wear mechanisms due to nanofluid Wear depth (μm) Ra (μm) Water Water+CE Water+FU Water Water+CE Water+FU Random Scratches Thick layer detached with scatter debris Wear debris Wear track Uniform grooves 16μm 16μm 16μm 19 Original Ti Surface Water+CE Water+FU

20 Shape effects on friction N-0%C 1N-0%C N-25%C coeffecient of friction N-25%C 1N-50%C 1N-75%C 3N-0%C 3N-25%C 3N-50%C 3N-75%C 5N-0%C 5N-25%C Coeffecient of friction N-50%C 1N-75%C 3N-0%C 3N-25%C 3N-50%C 3N-75%C 5N-0%C N-50%C N-25%C Sommerfield number 5N-75%C Sommerfield number 5N-50%C 5N-75%C ROD-SHAPED NANOPARTICLES SPHERICAL NANOPARTICLES 20

21 Effects of concentration on friction 21

22 NP fluid interaction Electrostatic attraction Positively charged particle + negative regions of protein CORONA Repulsive force Positively charged particle + positive regions of protein J. Klein, Proc. Natl Acad Sci USA 104 (2007) , 22

23 In CMP Interfacial forces in wafer-particle-pad interfaces van der Waals Electrostatic H-bond Fluid drag Friction F applied Polishing pad U Particle 1.4R F f F drag wafer F vdw +F F el +F H-bond 23

24 Interfacial forces as a function of particle radius 8 vdw electrostatic H-bond drag force v=0.1m/s drag force v=0.4m/s 6 log-force (nn) Particle diameter (μm) Ng & Liang, ASME J. Tribology (2007) 24

25 Modified Stribeck curve for CMP: Polyurethane-rotating motion Friction coefficient Friction Coefficient E E E E E Sommerfeld E+00 2.E-08 4.E-08 6.E-08 8.E-08 1.E-07 1.E-07 Modified Sommerfeld Number Without modification Modified Stribeck curve for rotational Polyurethane pad 25

26 Change in composite modulus for the polyurethane pad Modulus ( GPa) Load ( N) Composite modulus: E' = k N L Ebulk (1 α 2 ) 26

27 Summary 0.8 Water Friction Coefficient Crown Ether Fullerene Speed*Viscosity/Load 27

28 Outlook Novel nanomaterials emerge in near future New understanding is needed in nanomaterials-properties-tribological performance Unconventional applications 28