Investigation of initial and steady-state sliding behavior of a nearly-frictionless carbon film by imaging 2- and 3-D TOF-SIMS.

Journal Article · Sat Dec 01 04:00:00 EST 2007 · Tribology Lett.

DOI:https://doi.org/10.1007/s11249-007-9268-z· OSTI ID:920559

Eryilmaz, O L; Erdemir, A

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 plasma-enhanced 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.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: EE
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 920559
• Report Number(s): ANL/ES/JA-58945
• Journal Information: Tribology Lett., Journal Name: Tribology Lett. Journal Issue: 3 ; Dec. 2007 Vol. 28
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

03 NATURAL GAS
08 HYDROGEN
36 MATERIALS SCIENCE
CARBON
CHEMICAL VAPOR DEPOSITION
FRICTION
HYDROGEN
MASS SPECTROSCOPY
METHANE
NITROGEN
OXYGEN
SLIDING FRICTION
SPATIAL DISTRIBUTION
SPECTRA
STEELS
SUBSTRATES
X-RAY PHOTOELECTRON SPECTROSCOPY