Analytical Sciences

Newly Developed Friction Tester for in situ Soft X-Ray Absorption Measurements of Frictional Engine-Oil/Metals Interfaces

Yasuji MURAMATSU,* Masaru OKUYAMA,** Naoko TAKAHASHI,** Toshihide OHMORI,** and Eric M. GULLIKSON***

*Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2201, Japan
**Toyota Central R&D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
***Center for X-Ray Optics, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA

A novel friction tester has been developed to clarify the friction mechanism between engine oil and metals by in situ/operando measurements of the X-ray absorption near edge structure (XANES) using the total electron yield (TEY) method. The tester can perform frictional motion with engine oil and metals in a vacuum chamber under a vacuum of 10⁻⁷ Torr during TEY-XANES measurements in BL-6.3.2 at the Advanced Light Source (ALS). From in situ XANES measurements in the C K and Fe L regions, the organic molecule layers at the oil/metals interfaces have been successfully observed.

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