Dynamics of dual film formation in boundary lubrication of steels part III. Real time monitoring with ellipsometry

Abstract

Effective "breaking-in" of lubricated steel surfaces has been found to be due primarily to the rate of growth of "protective" films of oxides and compounds derived from the lubricant. The protection afforded by the films is strongly dependent on lubricant chemistry, steel composition, original surface roughness and the load/speed sequence or history in the early stages of sliding. Given the great number of variables involved it is not possible to follow more than a few of the chemical changes on surfaces using the electron, ion and X-ray column analytical instruments at the end of experiments. Ellipsometry was therefore used to monitor the formation and loss of dual protective films in real time, and detailed chemical analysis was done at various stages to calibrate the ellipsometer. This work is reported in three interlinking parts: I, functional nature and mechanical properties; II, chemical analyses; III, real-time monitoring with ellipsometry.