VAPOR-PHASE LUBRICATION OF HIGH-TEMPERATURE BEARINGS

A ball-on-rod tester was modified to allow tricresylphosphate (TCP) to be vaporized into a carrier gas of air and delivered into the bottom section of the rolling contact tester operated at 3200 rpm. Tests were made using M50 rods and M50 balls at a pressure of 3.86 GPa and a tem perature of 350-degrees-C and with silicon nitride rods and balls at a contact pressure of 5.13 GPa and temperatures of 350-degrees-C and 68 0-degrees-C. Using a vaporized stream of 0.5% TCP to lubricate the rod and balls for test times from 90 minutes to 8 hours, a mild polishing occurred on the active bearing surfaces. SEM photographs of the vapor lubricated surface showed a distinct tenacious deposit on the ball ca ge, rod, and balls. These results indicate that vapor phase lubricatio n can be used for high pressure bearing contacts, providing effective lubrication for temperatures up to at least 680-degrees-C.