[Zurück]

R. Kolm, C. Pieczetowski, I. Gebeshuber:
"Isomer specific tribological behaviour of hydroxyquinolines";
in: "Abstract ECOTRIB Joint Europ. Conf. on Tribology and Final Conference of COST 532 action: Triboscience and Tribotechnology", Joint Europ. Conf. on Tribology and Final Conference of COST 532 action: Triboscience and Tribotechnology, 2007.

Abstract for the ECOTRIB Joint European Conference on Tribology and Final Conference of COST 532 action:
Triboscience and Tribotechnology, June 12-15, 2007, Ljubljana, Slovenia, http://www.ctd.uni-lj.si/ecotrib2007.htm
ISOMER SPECIFIC TRIBOLOGICAL BEHAVIOUR OF HYDROXYQUINOLINES
R. Kolm, C.A. Pieczetowski, I.C. Gebeshuber*
Institut f. Allgemeine Physik, Vienna University of Technology,
Wiedner Hauptstrasse 8-10/134, AUSTRIA
TEL: 43 1 58801 13436, Email: ille@iap.tuwien.ac.at
Abstract
Experiments from the macro- to the nanorange
show that different isomers of hydroxyquinoline have
different lubrication properties on tribologically relevant
surfaces, e.g. 100Cr6 steel or copper.
On the macroscale, highly refined low sulfur diesel
fuels with 2-, 4-, 6- and 8-hydroxyquinoline as additives
were tested by means of a high frequency reciprocating
rig tribometer (steel ball against steel plate). In this study,
attention was especially paid to the connection between
the position of the hydroxyl group at the molecule and
the resulting influence on the "lubricity" properties of
low sulfur diesel fuel. 2- and 8-hydroxyquinoline showed
excellent wear reducing behaviour, even at
concentrations as low as 125ppm. Of these two isomers,
2-hydroxyquinoline had the larger potential for film
formation, even at low concentration [1].
The molecular level of the tribo-system was
investigated by means of angle resolved X-ray
photoelectron spectroscopy (VG ESCALAB Mk III
equipped with a special preparation chamber, permitting
the transfer of samples from a fluid cell to the analysis
chamber under Helium protective gas) [2].
Monomolecular lubricant films were deposited from the
liquid phase onto ultra thin copper films sputtered onto
silicon wafers as well as onto 100Cr6 steel plates.
Spectra of the samples immerged into the lubricating
fluid and after tribotesting were recorded. It showed that
the tribological behaviour of the additives on copper is
contrary to their behaviour on steel. Angular resolved
XPS investigation of 8-hydroxychinoline on copper
samples demonstrated that, without tribological stress,
full coverage of the surface with 8-hydroxyquinoline is
not possible. Furthermore, XPS revealed that the
additives undergo reactions during adsorption. After
tribotesting different compositions of the tribofilms were
found for the various isomers tested.
The results from the macroscopic level were
reproduced on the nanoscopic level by atomic force
microscopy measurements (MFP-3D, Asylum Research,
Santa Barbara, CA, USA). An isomer specific reduction
of friction was found [3].
Fig. 1: The different hydroxyquinoline isomers tested
for their wear behaviour by reciprocating rig method, by
angle resolved photoelectron spectroscopy and by
atomic force microscopy: 2-, 4-, 6- and 8-hydroxyquinoline
(top left, top right, bottom left, bottom right).
References
[1] R. Kolm, et al., in: "Life Cycle Tribology in:
Tribology and Interface Engineering Series",
Elsevier, Amsterdam/NL, (2005) 269.
[2] H. Störi, et al., Proc. 14th Int. Colloquium Tribology,,
Technische Akademie Esslingen, III (2004) 1663.
[3] Gebeshuber I.C., et al., submitted