Nanotribological Behavior of Carbon Based Thin Films: Friction and Lubricity Mechanisms at the Nanoscale

Abstract

The use of materials with very attractive friction and wear properties has raised much attention in research and industrial sectors. A wide range of tribological applications, including rolling and sliding bearings, machining, mechanical seals, biomedical implants and microelectromechanical systems (MEMS), require thin films with high mechanical strength, chemical inertness, broad optical transparency, high refractive index, wide bandgap excellent thermal conductivity and extremely low thermal expansion. Carbon based thin films like diamond, diamond-like carbon, carbon nitride and cubic boron nitride known as “super-hard” material have been studied thoroughly as the ideal candidate for tribological applications. In this study, the results of experimental and simulation works on the nanotribological behavior of carbon films and fundamental mechanisms of friction and lubricity at the nano-scale are reviewed. The study is focused on the nanomechanical properties and analysis of the nanoscratching processes at low loads to obtain quantitative analysis, the comparison obtain quantitative analysis, the comparison of their elastic/plastic deformation response, and nanotribological behavior of the a-C, ta-C, a-C:H, CNx, and a-C:M films. For ta-C and a-C:M films new data are presented and discussed

Assessing the integrity of CFRPs through nanomechanical mapping: the effect of CF surface modification

“…The standard method is capable of providing information on the elastic recovery and plastic deformation [12], with unprecedented lateral and sub-surface displacement resolution. Additionally, nanoindentation may also be used in measuring mechanical properties such as fracture behaviour [13], hardening, strain rate sensitivity, residual stress [14] and size effects in plasticity on a local level [15].…”

Reducing Friction and Wear of Tribological Systems through Hybrid Tribofilm Consisting of Coating and Lubricants

“…In general, hard coatings make the friction coefficient higher, because of their high interfacial shear strengths [15,16]. Among the hard coatings, DLC is becoming quite widely used, because of its low friction, superior wear resistance and simple composition (only C and H) [17,18].…”

“…Among the hard coatings, DLC is becoming quite widely used, because of its low friction, superior wear resistance and simple composition (only C and H) [17,18]. DLC can be applied to machine component surfaces operating in dry, as well as lubricated conditions [16]. When DLC is applied to machine component surfaces operating in lubricated systems, conventional lubricants formulated for a steel/steel surface are still used for DLC coated surfaces.…”

Novel method for in-situ and simultaneous nanofriction and nanowear characterization of materials

“…It has been previously shown that water acts as a lubricant for DLC coatings 19,23 . The lubricating action of the water can be explained as a result of a "three-body interaction" where the water reduces the adhesion between the surfaces in contact.…”

“…These amorphous films are a mix of sp 3 tetrahedral bonding (like in single-crystal diamonds) and sp 2 trigonal bonding (like in single-crystal graphite), and usually deposited by physical or chemical vapor deposition techniques 14 . Since Bhushan published the first nanotribological study of amorphous carbon films using an atomic force microscope (AFM) 15 , there have been many studies about the nanotribological properties of carbon-based coatings, as it has been reviewed for dry and lubricated conditions [16][17][18][19][20][21][22] . We can observe that for dry tests (Figure 8a), the friction coefficient decreases with the increase of the applied load from 10 µN to 100 µN, and stays constant when increasing from 100 µN to 1000 µN.…”