Speed and Atmosphere Influences on Nanotribological Properties of NbSe2

摘要

Nanotribological properties of NbSe2 are studied using an atomic friction force microscope. The friction force is measured as a function of normal load and scan speeds ranging from 10 nm s?1 to 40 μm s?1 under two atmospheres (air and argon). At low speed, no effect of atmosphere is noticed and a linear relationship between the friction and normal forces is observed leading to a friction coefficient close to 0.02 for both atmospheres. At high speed, the tip/surface contact obeys the JKR theory and the tribological properties are atmosphere dependent: the shear stress measured in air environment is three times lower than the one measured under argon atmosphere. A special attention is paid to interpret these results through numerical data obtained from a simple athermal model based on Tomlinson approach.