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), tran smission electron microscopy (TEM) and Auger spectroscopy (AES) were employ ed to analyse the surface layers of the wear scars. The increased temperatu re at the contact of ceramic balls and steel plates induced tribochemical r eactions of the material with chemical species from the environment. Ln con trast to the tribolayer created under non-lubricated conditions where oxida tion of silicon nitride and steel is a wear determining mechanism, at oil-l ubricated contacts carbonisation of steel due to oil decomposition takes pl ace. (C) 1999 Elsevier Science S.A. All rights reserved.