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MM: Metall- und Materialphysik
MM 23: Mechanical Properties I
MM 23.3: Talk
Wednesday, March 29, 2006, 14:30–14:45, IFW B
Friction and adhesion of selected bearing materials in vacuum — •Mikhail Kosinsky1,2, Yonghe Liu1, Wolfram Hild1, and Juergen A. Schaefer1 — 1Technische Universität Ilmenau, Institut für Physik und Zentrum für Mikro- und Nanotechnologien, Postfach 100565, 98684 Ilmenau, Germany — 2Bauman Moscow State Technical University, MT-11, BMSTU, 2nd Baumanskaya 5, Moscow, 105005, Russia
There is a strong interaction between the contact surfaces of bearings in vacuum. It may lead to high adhesion and high friction that can deteriorate the performance of positioning systems transported by bearings. We characterize the friction and adhesion of selected pairs of bearing materials including steel, copper, gold, sapphire and Si3N4 in high vacuum. A driving unit based on piezoelements were built in a vacuum (10−8 - 10−6 Torr) chamber, which can be refilled with various atmospheres (O2, N2). The load prescribed by the driving unit was applied to a glass cantilever through which a sphere was in contact with a specimen. We obtained the normal load and friction force by measuring the deflection of the cantilever in normal and lateral direction and multiplying the spring constants. A laser interferometer mounted outside of the vacuum chamber was employed to measure the deflection. The gas composition was monitored by an in-situ mass spectroscopy. The results were discussed with respect to the changes of normal load, velocity and gas composition.