The thermal contact resistance of lubricant films in vacuum

This paper presents the results of an experimental investigation on the thermal contact resistance of lubricant films and bare interfaces. The apparatus and procedure used in the determination of these resistances are described. Twelve series of tests were performed to evaluate the effects of temperature and contact pressure on the thermal resistance of lubricant films. Variations of thermal contact resistance with temperature and contact pressure for four lubricants and for bare interfaces are presented graphically. The thermal resistances of the four lubricants tested in vacuum conditions: lithium grease, graphite grease, molykote grease, and silicone lubricant, were found to lie in the range from 0.0004 to 0.0035 hr sq ft F/Btu. The thermal resistances of the four lubricants in vacuum were lower than the thermal resistance for bare interfaces in air, and one order of magnitude lower than the thermal resistance of bare interfaces in vacuum. The molykote grease was least affected by temperature --Abstract, page ii