"Super-low friction of ta-C coating in presence of oleic acid" by Makoto KANO, Jean Michel MARTIN et al.

Article Title

Super-low friction of ta-C coating in presence of oleic acid

Authors

Makoto KANO, Division of Mechanical & Material Engineering, Kanagawa Industrial Technology Center 705-1 Shimo-Imaizumi, Ebina, Kanagawa, Japan
Jean Michel MARTIN, LTDS, Ecole Centrale de Lyon 69380, Ecully, France
Kentaro YOSHIDA, Division of Mechanical & Material Engineering, Kanagawa Industrial Technology Center 705-1 Shimo-Imaizumi, Ebina, Kanagawa, Japan
Maria Isabel DE BARROS BOUCHET, LTDS, Ecole Centrale de Lyon 69380, Ecully, France

Keywords

epoxy composite, short carbon fiber, friction, wear

Abstract

Friction tests have been carried out on bearing steel friction pairs coated with a-C:H and ta-C under lubricated conditions with 1-hexadecene and pure oleic acid, respectively. Main results show that ta-C leads to the super-low regime with oleic acid (friction coefficient below 0.01) and that a-C:H is quite well lubricated by 1-hexadecen. Surface analyses by coupling X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) have been carried out in the case of oleic acid with ta-C and a-C:H coatings. Results show that tribochemical reactions have occurred. OH groups terminate the ta-C surface whereas a-C:H is covered by a thin tribofilm and is terminated by oleic acid monolayers. The superlow regime in the case of ta-C is mainly attributed to the presence of the OH-termination.