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Understanding of lubrication with neutrons
Author(s) -
Wolff M.,
Magerl A.,
Frick B.,
Zabel H.
Publication year - 2003
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.200390113
Subject(s) - lubrication , lubricant , materials science , quartz crystal microbalance , shear (geology) , thermal , mechanics , composite material , forensic engineering , chemistry , thermodynamics , engineering , physics , organic chemistry , adsorption
Abstract Lubrication is an old but nevertheless barely understood phenomenon. Insufficient lubrication leads to permanent wear, causing an estimated damage in the USA of about 6 % of the GNP [1]. Already the Egyptian civilisation was aware of the usefulness of lubricants. The painting from the grotto at El‐Bershed dated about 1880 B.C. shows the use of a lubricant to spare the power of men [2]. In recent years new sophisticated experimental techniques like surface force apparatus [3, 4], friction force microscopy [3, 5] and quartz‐crystal microbalance [6] have been employed to test theories and computer simulations [3, 7] of friction mechanism. However, these methods cannot provide in situ information of the sliding action and the dynamical response on a molecular level. The large penetration power of thermal neutrons allow non‐destructive studies of samples in complex environments. Combining this with an outstanding energy resolution makes it possible to study simultaneously the macroscopic flow and the microscopic diffusion of flowing liquids. For a commercial motor oil we found surface slip. In addition, under shear the microscopic diffusion becomes anisotrop.