OPTICAL AND LEAD-FILMED MICROSCOPY OF LEAD-FILMED BALL-BEARINGS AFTER LONG USAGE IN HIGH VACUUM

摘要

ESTL have examined a number of lead-lubricated angular contact bearings from Marconi Space and Defence Systems Ltd (MSDS) which has run successfully for long periods in high vacuum. These bearings fall into three categories: (i) Tool steel without cage;(ii) Tool steel with lead bronze cage: (iii) EN31 (52100) steel with lead bronze cage. The bearing surfaces of the balls and races have been examined using optical microscopy, electron scanning microscopy with energy-dispersive X-ray analysis, and traditional electron probe microanalysis. It was found in the cageless tool steel bearing that the wear debris formed by ball-to-ball contact was selectively enriched with the discontinuous high tungsten phase from the tool steel. This debris was present on the raceways and balls but was insufficient to cause seizure in these high clearance, radially loaded bearings.