The tribological properties of graphite M210 seal material under high temperature were investigated on a HT-1000 high temperature friction/wear tester.The worn surface of graphite pin was observed by scanning electronic microscope (SEM).The predication model on friction coefficient and wear rate was established by grey theory GM (1

1) based on the test data.The results show that the friction coefficient of graphite M210 seal material gradually augmented

then gradually diminished

and reached a steady value with the test time.The value of friction coefficient was minimal when the temperature was 450℃.The wear rate increased with the temperature rise.The worn surface was characterized by obvious adhesion

laceration and unordered plastic flow under temperature 300℃.The plastic flow trace had obvious directivity

and the desquamation and the rift were found on the worn surface when the temperature was above 400℃.The lubrication action was mostly dependent of the physically absorbed film by water vapor at lower temperature.With the temperature rise

the lubrication action turned to reaction film

and the lubrication of physical adsorbed film disappeared.The predication model for friction coefficient and wear rate was established based on test data by the gray theory

and the precision grade of the model was the first grade by the grade verification.