RETAINER-DEPENDENT WEAR OF SILICON-NITRIDE BEARINGS AT HIGH-TEMPERATURES

Several retainer materials for high-temperature silicon nitride bearin gs to be used in air were examined with a high-temperature rolling thr ee-ball tester. The ''soft'' or ''self-lubricating'' retainer material s (metal-bonded MoS2-WS2 alloys, a carbon-carbon composite and graphit e) tended to yield longer bearing life, lower silicon nitride wear rat e and lower traction coefficients than the hard retainers (Fe-based si ntered alloys, chromia and silicon nitride). The main problem in the u se of the self-lubricating retainer materials was their rapid wear by tribo-oxidation at high temperatures.