Aimed at the friction pairs of impregnated phosphate graphite (M234Ao) and 9Cr18Mo stainless steel commonly used in aeroengine graphite seal,the ball-on-disk and pin-on-disk contact friction tests were conducted on the UMT-TriboLab testing machine.The friction and wear properties of the friction pair of M234Ao and 9Cr18Mo under the conditions of low-speed and light load,high-speed and heavy load,dry friction and oil lubrication were studied.The surface of the friction pair was observed and analyzed by contact profiler and metallurgical microscope,and the wear mechanism was analyzed.The results indicate that the friction coefficient and wear rate under oil lubrication and surface to surface contact are significantly lower than those under dry friction and point to surface contact.Adding oil medium can reduce the intensity of interfacial friction,inhibit metal oxidation and reduce the friction coefficient,especially under the condition of high speed and heavy load.The wear mechanism of the the friction pair of M234Ao and 9Cr18Mo is mainly abrasive wear and adhesive wear,accompanied by furrow,micro crack and scratch.