Interactions in silicon nitride ceramics vs. steel contact under fretting conditions

The wear of silicon nitride and bearing steel under oil-lubricated fretting conditions was investigated and the mechanisms involved studied. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Auger spectroscopy (AES) were employed to analyse the surface layers of the wear scars. The increased temperature at the contact of ceramic balls and steel plates induced tribochemical reactions of the material with chemical species from the environment. Ln contrast to the tribolayer created under non-lubricated conditions where oxidation of silicon nitride and steel is a wear determining mechanism, at oil-lubricated contacts carbonisation of steel due to oil decomposition takes place. (C) 1999 Elsevier Science S.A. All rights reserved.