A rolling bearing in which rolling elements, alternatively, the rolling elements and a pair of races are made of a ceramic material prepared by sintering a sintering material of silicon nitride containing an MgAl.sub.2 O.sub.4 of spinel structure and at least silicon oxide selected between silicon oxide...http://www.google.es/patents/US5575571?utm_source=gb-gplus-sharePatente US5575571 - Rolling bearing
