Thermal desorption of hydrogen from the diamond C(100) surface

Su, Chun; Lin, Jung-Charng

doi:10.1016/s0039-6028(98)00107-1

Cited by 85 publications

(30 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hydrogen has a high chemical affinity toward carbon and bonds to it very strongly (C-H bonding is stronger than single C-C bonding) and, hence, is difficult to remove from the sliding surfaces easily [21]. Given these conditions, it is quite possible that almost all of the carbon atoms on the sliding surface of NFC are terminated by hydrogen, thus making such surfaces chemically inert and tribologically lubricious.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Initial and Steady-State Sliding Behavior of a Nearly Frictionless Carbon Film by Imaging 2- and 3-D TOF-SIMS

Eryilmaz

Erdemir

2007

Tribol Lett

View full text Add to dashboard Cite

Using imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS), we investigated the initial and steady-state sliding behavior of a nearly frictionless carbon (NFC) film. Specifically, TOF-SIMS images (both 2-D and 3-D) of these surfaces were constructed to highlight the spatial distributions of ionized and molecular species that were present on as-received and friction-tested NFC surfaces and as a function of depth. As a complementary technique, we used X-ray photoelectron spectroscopy (XPS) to gain further insight into the chemical nature of the sliding surfaces. The NFC films were produced on Si wafers and steel substrates in a gas discharge plasma that consisted of 25 vol.% methane and 75 vol.% hydrogen using a plasmaenhanced chemical vapor deposition (PECVD) system. They were then subjected to sliding friction and wear experiments in a pin-on-disk machine under 5-and 10-N loads and at sliding velocities of 0.2-0.5 m/s in dry nitrogen. The initial friction coefficients of the NFC films were in the range of 0.05-0.1, but decreased rapidly to values less than 0.01 at steady state. Positive and negative TOF-SIMS spectra and 2-and 3-D images reconstructed from selected masses revealed that the elemental distribution of certain chemical species differs substantially between undisturbed and tribo-tested areas of the NFC films. Specifically, the tribo-tested areas are essentially made up of carbon and hydrogen, while undisturbed or as-received areas are covered by a layer that is rich in oxygen and other species. These findings correlate well with the initial and steady-state friction coefficients of these films and help further explain their superlubricity in inert test environments.

show abstract

Section: Resultsmentioning

confidence: 99%

Investigation of Initial and Steady-State Sliding Behavior of a Nearly Frictionless Carbon Film by Imaging 2- and 3-D TOF-SIMS

Eryilmaz

Erdemir

2007

Tribol Lett

View full text Add to dashboard Cite

show abstract

“…As discussed above in detail, hydrogen bonds strongly to carbon and thus effectively passivates any free σ-bonds available within the bulk or on the surfaces [62]. Such a strong bonding and passivation of dangling σ-bonds can effectively reduce or even eliminate the extent of adhesive interactions across the sliding contact interface, thus resulting in super-low friction.…”

Section: Fundamental Lubrication Mechanismsmentioning

confidence: 99%

“…It is known that carbon bonds very strongly to hydrogen and has a high affinity to react with it when available. Due to such strong bonding, thermal desorption of hydrogen from a solid carbon material does not occur below 700 °C [62].…”

Section: Achieving Superlubricity In Dlc Films By Controlled Tribochementioning

confidence: 99%

Achieving superlubricity in DLC films by controlling bulk, surface, and tribochemistry

2014

View full text Add to dashboard Cite

Superlubricity refers to a sliding regime in which contacting surfaces move over one another without generating much adhesion or friction [1]. From a practical application point of view, this will be the most ideal tribological situation for many moving mechanical systems mainly because friction consumes large amounts of energy and causes greenhouse gas emissions [2]. Superlubric sliding can also improve performance and durability of these systems. In this paper, we attempt to provide an overview of how controlled or targeted bulk, surface, or tribochemistry can lead to superlubricity in diamond-like carbon (DLC) films. Specifically, we show that how providing hydrogen into bulk and near surface regions as well as to sliding contact interfaces of DLC films can lead to super-low friction and wear. Incorporation of hydrogen into bulk DLC or near surface regions can be done during deposition or through hydrogen plasma treatment after the deposition. Hydrogen can also be fed into the sliding contact interfaces of DLCs during tribological testing to reduce friction. Due to favorable tribochemical interactions, these interfaces become very rich in hydrogen and thus provide super-low friction after a brief run-in period. Regardless of the method used, when sliding surfaces of DLC films are enriched in hydrogen, they then provide some of the lowest friction coefficients (i.e., down to 0.001). Time-of-flight secondary ion mass spectrometer (TOF-SIMS) is used to gather evidence on the extent and nature of tribochemical interactions with hydrogen. Based on the tribological and surface analytical findings, we provide a mechanistic model for the critical role of hydrogen on superlubricity of DLC films.

show abstract

“…During contact sliding processes, this nonstoichiometric hydrocarbons transfer to counterpart ball. It is important to note that the C-H bonding is very strong (i.e., stronger than single C-C bond) and that thermal desorption of hydrogen from carbon-based films does not occur below 1,000 K [45]. Therefore, the C-H bonds do not break easily during sliding processes.…”

Section: Discussionmentioning

confidence: 99%

Ultralow Friction Behaviors of Hydrogenated Fullerene-Like Carbon Films: Effect of Normal Load and Surface Tribochemistry

Wang

Zhang

et al. 2010

Tribol Lett

View full text Add to dashboard Cite

Friction and wear behaviors of hydrogenated fullerene-like (H-FLC) carbon films sliding against Si 3 N 4 ceramic balls were performed at different contact loads from 1 to 20 N on a reciprocating sliding tribometer in air. It was found that the films exhibited non-Amontonian friction behaviors, the coefficient of friction (COF) decreased with normal contact load increasing: the COF was *0.112 at 1 N contact load, and deceased to ultralow value (*0.009) at 20 N load. The main mechanism responsible for low friction and wear under varying contact pressure is governed by hydrogenated carbon transfer film that formed and resided at the sliding interfaces. In addition, the unique fullerene-like structures induce well elastic property of the H-FLC films (elastic recovery 78%), which benefits the high load tolerance and induces the low wear rate in air condition. For the film with an ultralow COF of 0.009 tested under 20 N load in air, time of flight secondary ion mass spectrometry (ToF-SIMS) signals collected inside and outside the wear tracks indicated the presence of C 2 H 3 -and C 2 H 5 -fragments after tribological tests on the H-FLC films surface. We think that the tribochemistry and elastic property of the H-FLC films is responsible for the observed friction behaviors, the high load tolerance, and chemical inertness of hydrogenated carbon-containing transfer films instead of the graphitization of transfer films is responsible for the steady-state low coefficients of friction, wear, and interfacial shear stress.

show abstract

Thermal desorption of hydrogen from the diamond C(100) surface

Cited by 85 publications

References 59 publications

Investigation of Initial and Steady-State Sliding Behavior of a Nearly Frictionless Carbon Film by Imaging 2- and 3-D TOF-SIMS

Investigation of Initial and Steady-State Sliding Behavior of a Nearly Frictionless Carbon Film by Imaging 2- and 3-D TOF-SIMS

Achieving superlubricity in DLC films by controlling bulk, surface, and tribochemistry

Ultralow Friction Behaviors of Hydrogenated Fullerene-Like Carbon Films: Effect of Normal Load and Surface Tribochemistry

Contact Info

Product

Resources

About