Friction in the Microtribosystems.Influence of Condensed Water

Abstract

To evaluate the influence of condensed water on the rolling friction in the microtribosystems, the authors used a micro tribometer consisting in a driving rotational disc in contact with 3 microballs which sustain an inertially driven rotational disc. The driving disc has a constant rotational speed and the rotational motion is transmitted from the driving disc to the inertially driven disc by friction between the rolling contacts realized by the microballs and the two discs. A camera monitors the angular position of the inertially driven disc, from the start to the synchronism rotation and friction coefficient between the microballs and the inertial disc was determined as a function of the angular acceleration of the inertial disc. Experimental investigations were realized with the microballs having the diameter of 1.588 mm, 2.0 mm and 4.762 mm loaded with normal load of 9.42 mN both in dry conditions and in presence of condensed water on surfaces. The presence of the condensed water on the surfaces leads to the increase on the rolling friction coefficient, depending of the microballs diameter.